git.delta.rocks / unique-network / refs/commits / 4e76702c569f

--- a/tests/src/addToContractWhiteList.test.ts
+++ b/tests/src/addToContractWhiteList.test.ts
@@ -3,25 +3,25 @@
 // file 'LICENSE', which is part of this source code package.
 //
 
-import chai from "chai";
+import chai from 'chai';
 import chaiAsPromised from 'chai-as-promised';
-import usingApi, { submitTransactionAsync, submitTransactionExpectFailAsync } from "./substrate/substrate-api";
-import privateKey from "./substrate/privateKey";
+import usingApi, { submitTransactionAsync, submitTransactionExpectFailAsync } from './substrate/substrate-api';
+import privateKey from './substrate/privateKey';
 import {
-  deployFlipper
-} from "./util/contracthelpers";
+  deployFlipper,
+} from './util/contracthelpers';
 import {
-  getGenericResult, normalizeAccountId
-} from "./util/helpers"
+  getGenericResult,
+} from './util/helpers';
 
 chai.use(chaiAsPromised);
 const expect = chai.expect;
 
 describe('Integration Test addToContractWhiteList', () => {
 
-  it(`Add an address to a contract white list`, async () => {
+  it('Add an address to a contract white list', async () => {
     await usingApi(async api => {
-      const bob = privateKey("//Bob");
+      const bob = privateKey('//Bob');
       const [contract, deployer] = await deployFlipper(api);
 
       const whiteListedBefore = (await api.query.nft.contractWhiteList(contract.address, bob.address)).toJSON();
@@ -35,9 +35,9 @@
     });
   });
 
-  it(`Adding same address to white list repeatedly should not produce errors`, async () => {
+  it('Adding same address to white list repeatedly should not produce errors', async () => {
     await usingApi(async api => {
-      const bob = privateKey("//Bob");
+      const bob = privateKey('//Bob');
       const [contract, deployer] = await deployFlipper(api);
 
       const whiteListedBefore = (await api.query.nft.contractWhiteList(contract.address, bob.address)).toJSON();
@@ -58,11 +58,11 @@
 
 describe('Negative Integration Test addToContractWhiteList', () => {
 
-  it(`Add an address to a white list of a non-contract`, async () => {
+  it('Add an address to a white list of a non-contract', async () => {
     await usingApi(async api => {
-      const alice = privateKey("//Bob");
-      const bob = privateKey("//Bob");
-      const charlieGuineaPig = privateKey("//Charlie");
+      const alice = privateKey('//Bob');
+      const bob = privateKey('//Bob');
+      const charlieGuineaPig = privateKey('//Charlie');
 
       const whiteListedBefore = (await api.query.nft.contractWhiteList(charlieGuineaPig.address, bob.address)).toJSON();
       const addTx = api.tx.nft.addToContractWhiteList(charlieGuineaPig.address, bob.address);
@@ -74,10 +74,10 @@
     });
   });
 
-  it(`Add to a contract white list using a non-owner address`, async () => {
+  it('Add to a contract white list using a non-owner address', async () => {
     await usingApi(async api => {
-      const bob = privateKey("//Bob");
-      const [contract, deployer] = await deployFlipper(api);
+      const bob = privateKey('//Bob');
+      const [contract] = await deployFlipper(api);
 
       const whiteListedBefore = (await api.query.nft.contractWhiteList(contract.address, bob.address)).toJSON();
       const addTx = api.tx.nft.addToContractWhiteList(contract.address, bob.address);

--- a/tests/src/addToWhiteList.test.ts
+++ b/tests/src/addToWhiteList.test.ts
@@ -1,87 +1,87 @@
-//
-// This file is subject to the terms and conditions defined in
-// file 'LICENSE', which is part of this source code package.
-//
-
-import { IKeyringPair } from '@polkadot/types/types';
-import chai from 'chai';
-import chaiAsPromised from 'chai-as-promised';
-import privateKey from './substrate/privateKey';
-import usingApi, { submitTransactionExpectFailAsync } from './substrate/substrate-api';
-import {
-  addToWhiteListExpectSuccess,
-  createCollectionExpectSuccess,
-  createItemExpectSuccess,
-  destroyCollectionExpectSuccess,
-  enablePublicMintingExpectSuccess,
-  enableWhiteListExpectSuccess,
-  normalizeAccountId,
-} from './util/helpers';
-
-chai.use(chaiAsPromised);
-const expect = chai.expect;
-
-let Alice: IKeyringPair;
-let Bob: IKeyringPair;
-
-describe('Integration Test ext. addToWhiteList()', () => {
-
-  before(async () => {
-    await usingApi(async (api) => {
-      Alice = privateKey('//Alice');
-      Bob = privateKey('//Bob');
-    });
-  });
-
-  it('Execute the extrinsic with parameters: Collection ID and address to add to the white list', async () => {
-    const collectionId = await createCollectionExpectSuccess();
-    await addToWhiteListExpectSuccess(Alice, collectionId, Bob.address);
-  });
-
-  it('Whitelisted minting: list restrictions', async () => {
-    const collectionId = await createCollectionExpectSuccess();
-    await addToWhiteListExpectSuccess(Alice, collectionId, Bob.address);
-    await enableWhiteListExpectSuccess(Alice, collectionId);
-    await enablePublicMintingExpectSuccess(Alice, collectionId);
-    await createItemExpectSuccess(Bob, collectionId, 'NFT', Bob.address);
-  });
-});
-
-describe('Negative Integration Test ext. addToWhiteList()', () => {
-
-  it('White list an address in the collection that does not exist', async () => {
-    await usingApi(async (api) => {
-      // tslint:disable-next-line: no-bitwise
-      const collectionId = parseInt((await api.query.nft.createdCollectionCount()).toString()) + 1;
-      const Bob = privateKey('//Bob');
-
-      const tx = api.tx.nft.addToWhiteList(collectionId, normalizeAccountId(Bob.address));
-      await expect(submitTransactionExpectFailAsync(Alice, tx)).to.be.rejected;
-    });
-  });
-
-  it('White list an address in the collection that was destroyed', async () => {
-    await usingApi(async (api) => {
-      const Alice = privateKey('//Alice');
-      const Bob = privateKey('//Bob');
-      // tslint:disable-next-line: no-bitwise
-      const collectionId = await createCollectionExpectSuccess();
-      await destroyCollectionExpectSuccess(collectionId);
-      const tx = api.tx.nft.addToWhiteList(collectionId, normalizeAccountId(Bob.address));
-      await expect(submitTransactionExpectFailAsync(Alice, tx)).to.be.rejected;
-    });
-  });
-
-  it('White list an address in the collection that does not have white list access enabled', async () => {
-    await usingApi(async (api) => {
-      const Alice = privateKey('//Alice');
-      const Ferdie = privateKey('//Ferdie');
-      const collectionId = await createCollectionExpectSuccess();
-      await enableWhiteListExpectSuccess(Alice, collectionId);
-      await enablePublicMintingExpectSuccess(Alice, collectionId);
-      const tx = api.tx.nft.createItem(collectionId, normalizeAccountId(Ferdie.address), 'NFT');
-      await expect(submitTransactionExpectFailAsync(Ferdie, tx)).to.be.rejected;
-    });
-  });
-
-});
+//
+// This file is subject to the terms and conditions defined in
+// file 'LICENSE', which is part of this source code package.
+//
+
+import { IKeyringPair } from '@polkadot/types/types';
+import chai from 'chai';
+import chaiAsPromised from 'chai-as-promised';
+import privateKey from './substrate/privateKey';
+import usingApi, { submitTransactionExpectFailAsync } from './substrate/substrate-api';
+import {
+  addToWhiteListExpectSuccess,
+  createCollectionExpectSuccess,
+  createItemExpectSuccess,
+  destroyCollectionExpectSuccess,
+  enablePublicMintingExpectSuccess,
+  enableWhiteListExpectSuccess,
+  normalizeAccountId,
+} from './util/helpers';
+
+chai.use(chaiAsPromised);
+const expect = chai.expect;
+
+let Alice: IKeyringPair;
+let Bob: IKeyringPair;
+
+describe('Integration Test ext. addToWhiteList()', () => {
+
+  before(async () => {
+    await usingApi(async () => {
+      Alice = privateKey('//Alice');
+      Bob = privateKey('//Bob');
+    });
+  });
+
+  it('Execute the extrinsic with parameters: Collection ID and address to add to the white list', async () => {
+    const collectionId = await createCollectionExpectSuccess();
+    await addToWhiteListExpectSuccess(Alice, collectionId, Bob.address);
+  });
+
+  it('Whitelisted minting: list restrictions', async () => {
+    const collectionId = await createCollectionExpectSuccess();
+    await addToWhiteListExpectSuccess(Alice, collectionId, Bob.address);
+    await enableWhiteListExpectSuccess(Alice, collectionId);
+    await enablePublicMintingExpectSuccess(Alice, collectionId);
+    await createItemExpectSuccess(Bob, collectionId, 'NFT', Bob.address);
+  });
+});
+
+describe('Negative Integration Test ext. addToWhiteList()', () => {
+
+  it('White list an address in the collection that does not exist', async () => {
+    await usingApi(async (api) => {
+      // tslint:disable-next-line: no-bitwise
+      const collectionId = parseInt((await api.query.nft.createdCollectionCount()).toString()) + 1;
+      const Bob = privateKey('//Bob');
+
+      const tx = api.tx.nft.addToWhiteList(collectionId, normalizeAccountId(Bob.address));
+      await expect(submitTransactionExpectFailAsync(Alice, tx)).to.be.rejected;
+    });
+  });
+
+  it('White list an address in the collection that was destroyed', async () => {
+    await usingApi(async (api) => {
+      const Alice = privateKey('//Alice');
+      const Bob = privateKey('//Bob');
+      // tslint:disable-next-line: no-bitwise
+      const collectionId = await createCollectionExpectSuccess();
+      await destroyCollectionExpectSuccess(collectionId);
+      const tx = api.tx.nft.addToWhiteList(collectionId, normalizeAccountId(Bob.address));
+      await expect(submitTransactionExpectFailAsync(Alice, tx)).to.be.rejected;
+    });
+  });
+
+  it('White list an address in the collection that does not have white list access enabled', async () => {
+    await usingApi(async (api) => {
+      const Alice = privateKey('//Alice');
+      const Ferdie = privateKey('//Ferdie');
+      const collectionId = await createCollectionExpectSuccess();
+      await enableWhiteListExpectSuccess(Alice, collectionId);
+      await enablePublicMintingExpectSuccess(Alice, collectionId);
+      const tx = api.tx.nft.createItem(collectionId, normalizeAccountId(Ferdie.address), 'NFT');
+      await expect(submitTransactionExpectFailAsync(Ferdie, tx)).to.be.rejected;
+    });
+  });
+
+});

--- a/tests/src/approve.test.ts
+++ b/tests/src/approve.test.ts
@@ -82,7 +82,7 @@
   let Charlie: IKeyringPair;
 
   before(async () => {
-    await usingApi(async (api) => {
+    await usingApi(async () => {
       Alice = privateKey('//Alice');
       Bob = privateKey('//Bob');
       Charlie = privateKey('//Charlie');

--- a/tests/src/block-production.test.ts
+++ b/tests/src/block-production.test.ts
@@ -3,14 +3,15 @@
 // file 'LICENSE', which is part of this source code package.
 //
 
-import usingApi from "./substrate/substrate-api";
-import { expect } from "chai";
-import { ApiPromise } from "@polkadot/api";
+import usingApi from './substrate/substrate-api';
+import { expect } from 'chai';
+import { ApiPromise } from '@polkadot/api';
 
 const BlockTimeMs = 12000;
 const ToleranceMs = 1000;
 
-async function getBlocks(api: ApiPromise): Promise<number[]> {
+/* eslint no-async-promise-executor: "off" */
+function getBlocks(api: ApiPromise): Promise<number[]> {
   return new Promise<number[]>(async (resolve, reject) => {
     const blockNumbers: number[] = [];
     setTimeout(() => reject('Block production test failed due to timeout.'), BlockTimeMs + ToleranceMs);
@@ -27,7 +28,7 @@
 describe('Block Production smoke test', () => {
   it('Node produces new blocks', async () => {
     await usingApi(async (api) => {
-      let blocks: number[] | undefined = await getBlocks(api);
+      const blocks: number[] | undefined = await getBlocks(api);
       expect(blocks[0]).to.be.lessThan(blocks[1]);
     });
   });

--- a/tests/src/burnItem.test.ts
+++ b/tests/src/burnItem.test.ts
@@ -4,16 +4,15 @@
 //
 
 import { default as usingApi, submitTransactionAsync, submitTransactionExpectFailAsync } from './substrate/substrate-api';
-import { Keyring } from "@polkadot/api";
-import { IKeyringPair } from "@polkadot/types/types";
+import { Keyring } from '@polkadot/api';
+import { IKeyringPair } from '@polkadot/types/types';
 import { 
   createCollectionExpectSuccess, 
   createItemExpectSuccess,
   getGenericResult,
   destroyCollectionExpectSuccess,
-  normalizeAccountId
+  normalizeAccountId,
 } from './util/helpers';
-import { nullPublicKey } from "./accounts";
 
 import chai from 'chai';
 import chaiAsPromised from 'chai-as-promised';
@@ -25,10 +24,10 @@
 
 describe('integration test: ext. burnItem():', () => {
   before(async () => {
-    await usingApi(async (api) => {
+    await usingApi(async () => {
       const keyring = new Keyring({ type: 'sr25519' });
-      alice = keyring.addFromUri(`//Alice`);
-      bob = keyring.addFromUri(`//Bob`);
+      alice = keyring.addFromUri('//Alice');
+      bob = keyring.addFromUri('//Bob');
     });
   });
 
@@ -139,10 +138,10 @@
 
 describe('Negative integration test: ext. burnItem():', () => {
   before(async () => {
-    await usingApi(async (api) => {
+    await usingApi(async () => {
       const keyring = new Keyring({ type: 'sr25519' });
-      alice = keyring.addFromUri(`//Alice`);
-      bob = keyring.addFromUri(`//Bob`);
+      alice = keyring.addFromUri('//Alice');
+      bob = keyring.addFromUri('//Bob');
     });
   });
 

--- a/tests/src/change-collection-owner.test.ts
+++ b/tests/src/change-collection-owner.test.ts
@@ -6,8 +6,8 @@
 import chai from 'chai';
 import chaiAsPromised from 'chai-as-promised';
 import privateKey from './substrate/privateKey';
-import { default as usingApi, submitTransactionAsync, submitTransactionExpectFailAsync } from "./substrate/substrate-api";
-import { createCollectionExpectSuccess, createCollectionExpectFailure, normalizeAccountId } from "./util/helpers";
+import { default as usingApi, submitTransactionAsync, submitTransactionExpectFailAsync } from './substrate/substrate-api';
+import { createCollectionExpectSuccess, normalizeAccountId } from './util/helpers';
 
 chai.use(chaiAsPromised);
 const expect = chai.expect;
@@ -32,7 +32,7 @@
 });
 
 describe('Negative Integration Test changeCollectionOwner(collection_id, new_owner):', () => {
-  it(`Not owner can't change owner.`, async () => {
+  it('Not owner can\'t change owner.', async () => {
     await usingApi(async api => {
       const collectionId = await createCollectionExpectSuccess();
       const alice = privateKey('//Alice');
@@ -48,7 +48,7 @@
       await createCollectionExpectSuccess();
     });
   });
-  it(`Can't change owner of not existing collection.`, async () => {
+  it('Can\'t change owner of not existing collection.', async () => {
     await usingApi(async api => {
       const collectionId = (1<<32) - 1;
       const alice = privateKey('//Alice');

--- a/tests/src/check-event/createMultipleItemsEvent.test.ts
+++ b/tests/src/check-event/createMultipleItemsEvent.test.ts
@@ -10,7 +10,7 @@
 import chaiAsPromised from 'chai-as-promised';
 import privateKey from '../substrate/privateKey';
 import usingApi, {submitTransactionAsync} from '../substrate/substrate-api';
-import { createCollectionExpectSuccess, createItemExpectSuccess, nftEventMessage } from '../util/helpers';
+import { createCollectionExpectSuccess, nftEventMessage } from '../util/helpers';
 
 chai.use(chaiAsPromised);
 const expect = chai.expect;

--- a/tests/src/collision-tests/admVsOwnerChanges.test.ts
+++ b/tests/src/collision-tests/admVsOwnerChanges.test.ts
@@ -1,55 +1,50 @@
-import { IKeyringPair } from '@polkadot/types/types';
-import chai from 'chai';
-import chaiAsPromised from 'chai-as-promised';
-import { alicesPublicKey, bobsPublicKey } from '../accounts';
-import getBalance from '../substrate/get-balance';
-import privateKey from '../substrate/privateKey';
-import usingApi, { submitTransactionAsync } from '../substrate/substrate-api';
-import waitNewBlocks from '../substrate/wait-new-blocks';
-import {
-  createCollectionExpectSuccess,
-  createItemExpectSuccess,
-  setCollectionSponsorExpectSuccess,
-} from '../util/helpers';
-
-chai.use(chaiAsPromised);
-const expect = chai.expect;
-let Alice: IKeyringPair;
-let Bob: IKeyringPair;
-let Ferdie: IKeyringPair;
-
-before(async () => {
-  await usingApi(async () => {
-    Alice = privateKey('//Alice');
-    Bob = privateKey('//Bob');
-    Ferdie = privateKey('//Ferdie');
-  });
-});
-
-describe('Admin vs Owner changes token: ', () => {
-  // tslint:disable-next-line: max-line-length
-  it('The collection admin changes the owner of the token and in the same block the current owner transfers the token to another address ', async () => {
-    await usingApi(async (api) => {
-      const collectionId = await createCollectionExpectSuccess();
-      const changeAdminTxBob = api.tx.nft.addCollectionAdmin(collectionId, Bob.address);
-      await submitTransactionAsync(Alice, changeAdminTxBob);
-      const timeoutPromise = (timeout: number) => new Promise((resolve) => setTimeout(resolve, timeout));
-      const changeAdminTxFerdie = api.tx.nft.addCollectionAdmin(collectionId, Ferdie.address);
-      await submitTransactionAsync(Bob, changeAdminTxFerdie);
-      const itemId = await createItemExpectSuccess(Ferdie, collectionId, 'NFT');
-      //
-      const changeOwner = api.tx.nft.transferFrom(Ferdie.address, Bob.address, collectionId, itemId, 1);
-      const approve = api.tx.nft.approve(Bob.address, collectionId, itemId, 1);
-      const sendItem = api.tx.nft.transfer(Alice.address, collectionId, itemId, 1);
-      await Promise.all
-      ([
-        changeOwner.signAndSend(Alice),
-        approve.signAndSend(Bob),
-        sendItem.signAndSend(Ferdie),
-      ]);
-      const itemBefore: any = await api.query.nft.nftItemList(collectionId, itemId);
-      expect(itemBefore.Owner).not.to.be.eq(Bob.address);
-      await timeoutPromise(20000);
-    });
-  });
-});
+import { IKeyringPair } from '@polkadot/types/types';
+import chai from 'chai';
+import chaiAsPromised from 'chai-as-promised';
+import privateKey from '../substrate/privateKey';
+import usingApi, { submitTransactionAsync } from '../substrate/substrate-api';
+import {
+  createCollectionExpectSuccess,
+  createItemExpectSuccess,
+} from '../util/helpers';
+
+chai.use(chaiAsPromised);
+const expect = chai.expect;
+let Alice: IKeyringPair;
+let Bob: IKeyringPair;
+let Ferdie: IKeyringPair;
+
+before(async () => {
+  await usingApi(async () => {
+    Alice = privateKey('//Alice');
+    Bob = privateKey('//Bob');
+    Ferdie = privateKey('//Ferdie');
+  });
+});
+
+describe('Admin vs Owner changes token: ', () => {
+  // tslint:disable-next-line: max-line-length
+  it('The collection admin changes the owner of the token and in the same block the current owner transfers the token to another address ', async () => {
+    await usingApi(async (api) => {
+      const collectionId = await createCollectionExpectSuccess();
+      const changeAdminTxBob = api.tx.nft.addCollectionAdmin(collectionId, Bob.address);
+      await submitTransactionAsync(Alice, changeAdminTxBob);
+      const timeoutPromise = (timeout: number) => new Promise((resolve) => setTimeout(resolve, timeout));
+      const changeAdminTxFerdie = api.tx.nft.addCollectionAdmin(collectionId, Ferdie.address);
+      await submitTransactionAsync(Bob, changeAdminTxFerdie);
+      const itemId = await createItemExpectSuccess(Ferdie, collectionId, 'NFT');
+      //
+      const changeOwner = api.tx.nft.transferFrom(Ferdie.address, Bob.address, collectionId, itemId, 1);
+      const approve = api.tx.nft.approve(Bob.address, collectionId, itemId, 1);
+      const sendItem = api.tx.nft.transfer(Alice.address, collectionId, itemId, 1);
+      await Promise.all([
+        changeOwner.signAndSend(Alice),
+        approve.signAndSend(Bob),
+        sendItem.signAndSend(Ferdie),
+      ]);
+      const itemBefore: any = await api.query.nft.nftItemList(collectionId, itemId);
+      expect(itemBefore.Owner).not.to.be.eq(Bob.address);
+      await timeoutPromise(20000);
+    });
+  });
+});

--- a/tests/src/collision-tests/admVsOwnerData.test.ts
+++ b/tests/src/collision-tests/admVsOwnerData.test.ts
@@ -1,54 +1,47 @@
-import { IKeyringPair } from '@polkadot/types/types';
-import chai from 'chai';
-import chaiAsPromised from 'chai-as-promised';
-import { alicesPublicKey, bobsPublicKey } from '../accounts';
-import getBalance from '../substrate/get-balance';
-import privateKey from '../substrate/privateKey';
-import usingApi, { submitTransactionAsync } from '../substrate/substrate-api';
-import waitNewBlocks from '../substrate/wait-new-blocks';
-import {
-  createCollectionExpectSuccess,
-  createItemExpectSuccess,
-  setCollectionSponsorExpectSuccess,
-} from '../util/helpers';
-
-chai.use(chaiAsPromised);
-const expect = chai.expect;
-let Alice: IKeyringPair;
-let Bob: IKeyringPair;
-let Ferdie: IKeyringPair;
-
-before(async () => {
-  await usingApi(async () => {
-    Alice = privateKey('//Alice');
-    Bob = privateKey('//Bob');
-    Ferdie = privateKey('//Ferdie');
-  });
-});
-
-describe('Admin vs Owner changes the data in the token: ', () => {
-  it('The collection admin changes the data in the token and in the same block the token owner also changes the data in it ', async () => {
-    await usingApi(async (api) => {
-      const AliceData = 1;
-      const BobData = 2;
-      const collectionId = await createCollectionExpectSuccess();
-      const changeAdminTx = api.tx.nft.addCollectionAdmin(collectionId, Bob.address);
-      await submitTransactionAsync(Alice, changeAdminTx);
-      const timeoutPromise = (timeout: number) => new Promise((resolve) => setTimeout(resolve, timeout));
-      const itemId = await createItemExpectSuccess(Bob, collectionId, 'NFT');
-      //
-      // tslint:disable-next-line: max-line-length
-      const AliceTx = api.tx.nft.setVariableMetaData(collectionId, itemId, AliceData.toString());
-      // tslint:disable-next-line: max-line-length
-      const BobTx = api.tx.nft.setVariableMetaData(collectionId, itemId, BobData.toString());
-      await Promise.all
-      ([
-        AliceTx.signAndSend(Alice),
-        BobTx.signAndSend(Bob),
-      ]);
-      const item: any = await api.query.nft.nftItemList(collectionId, itemId);
-      expect(item.VariableData).not.to.be.eq(null); // Pseudo-random selection of one of two values
-      await timeoutPromise(20000);
-    });
-  });
-});
+import { IKeyringPair } from '@polkadot/types/types';
+import chai from 'chai';
+import chaiAsPromised from 'chai-as-promised';
+import privateKey from '../substrate/privateKey';
+import usingApi, { submitTransactionAsync } from '../substrate/substrate-api';
+import {
+  createCollectionExpectSuccess,
+  createItemExpectSuccess,
+} from '../util/helpers';
+
+chai.use(chaiAsPromised);
+const expect = chai.expect;
+let Alice: IKeyringPair;
+let Bob: IKeyringPair;
+
+before(async () => {
+  await usingApi(async () => {
+    Alice = privateKey('//Alice');
+    Bob = privateKey('//Bob');
+  });
+});
+
+describe('Admin vs Owner changes the data in the token: ', () => {
+  it('The collection admin changes the data in the token and in the same block the token owner also changes the data in it ', async () => {
+    await usingApi(async (api) => {
+      const AliceData = 1;
+      const BobData = 2;
+      const collectionId = await createCollectionExpectSuccess();
+      const changeAdminTx = api.tx.nft.addCollectionAdmin(collectionId, Bob.address);
+      await submitTransactionAsync(Alice, changeAdminTx);
+      const timeoutPromise = (timeout: number) => new Promise((resolve) => setTimeout(resolve, timeout));
+      const itemId = await createItemExpectSuccess(Bob, collectionId, 'NFT');
+      //
+      // tslint:disable-next-line: max-line-length
+      const AliceTx = api.tx.nft.setVariableMetaData(collectionId, itemId, AliceData.toString());
+      // tslint:disable-next-line: max-line-length
+      const BobTx = api.tx.nft.setVariableMetaData(collectionId, itemId, BobData.toString());
+      await Promise.all([
+        AliceTx.signAndSend(Alice),
+        BobTx.signAndSend(Bob),
+      ]);
+      const item: any = await api.query.nft.nftItemList(collectionId, itemId);
+      expect(item.VariableData).not.to.be.eq(null); // Pseudo-random selection of one of two values
+      await timeoutPromise(20000);
+    });
+  });
+});

--- a/tests/src/collision-tests/admVsOwnerTake.test.ts
+++ b/tests/src/collision-tests/admVsOwnerTake.test.ts
@@ -1,54 +1,49 @@
-import { IKeyringPair } from '@polkadot/types/types';
-import chai from 'chai';
-import chaiAsPromised from 'chai-as-promised';
-import { alicesPublicKey, bobsPublicKey } from '../accounts';
-import getBalance from '../substrate/get-balance';
-import privateKey from '../substrate/privateKey';
-import usingApi, { submitTransactionAsync } from '../substrate/substrate-api';
-import waitNewBlocks from '../substrate/wait-new-blocks';
-import {
-  createCollectionExpectSuccess,
-  createItemExpectSuccess,
-  setCollectionSponsorExpectSuccess,
-} from '../util/helpers';
-
-chai.use(chaiAsPromised);
-const expect = chai.expect;
-let Alice: IKeyringPair;
-let Bob: IKeyringPair;
-let Ferdie: IKeyringPair;
-
-before(async () => {
-  await usingApi(async () => {
-    Alice = privateKey('//Alice');
-    Bob = privateKey('//Bob');
-    Ferdie = privateKey('//Ferdie');
-  });
-});
-
-describe('Admin vs Owner take token: ', () => {
-  // tslint:disable-next-line: max-line-length
-  it('The collection admin burns the token and in the same block the token owner performs a transaction on it ', async () => {
-    await usingApi(async (api) => {
-      const collectionId = await createCollectionExpectSuccess();
-      const changeAdminTx = api.tx.nft.addCollectionAdmin(collectionId, Bob.address);
-      await submitTransactionAsync(Alice, changeAdminTx);
-      const timeoutPromise = (timeout: number) => new Promise((resolve) => setTimeout(resolve, timeout));
-      const itemId = await createItemExpectSuccess(Bob, collectionId, 'NFT');
-      //
-      const sendItem = api.tx.nft.transfer(Ferdie.address, collectionId, itemId, 1);
-      const burnItem = api.tx.nft.burnItem(collectionId, itemId, 1);
-      await Promise.all
-      ([
-        sendItem.signAndSend(Bob),
-        burnItem.signAndSend(Alice),
-      ]);
-      await timeoutPromise(10000);
-      let itemBurn: boolean = false;
-      itemBurn = (await (api.query.nft.nftItemList(collectionId, itemId))).toJSON() as boolean;
-      // tslint:disable-next-line: no-unused-expression
-      expect(itemBurn).to.be.null;
-      await timeoutPromise(20000);
-    });
-  });
-});
+import { IKeyringPair } from '@polkadot/types/types';
+import chai from 'chai';
+import chaiAsPromised from 'chai-as-promised';
+import privateKey from '../substrate/privateKey';
+import usingApi, { submitTransactionAsync } from '../substrate/substrate-api';
+import {
+  createCollectionExpectSuccess,
+  createItemExpectSuccess,
+} from '../util/helpers';
+
+chai.use(chaiAsPromised);
+const expect = chai.expect;
+let Alice: IKeyringPair;
+let Bob: IKeyringPair;
+let Ferdie: IKeyringPair;
+
+before(async () => {
+  await usingApi(async () => {
+    Alice = privateKey('//Alice');
+    Bob = privateKey('//Bob');
+    Ferdie = privateKey('//Ferdie');
+  });
+});
+
+describe('Admin vs Owner take token: ', () => {
+  // tslint:disable-next-line: max-line-length
+  it('The collection admin burns the token and in the same block the token owner performs a transaction on it ', async () => {
+    await usingApi(async (api) => {
+      const collectionId = await createCollectionExpectSuccess();
+      const changeAdminTx = api.tx.nft.addCollectionAdmin(collectionId, Bob.address);
+      await submitTransactionAsync(Alice, changeAdminTx);
+      const timeoutPromise = (timeout: number) => new Promise((resolve) => setTimeout(resolve, timeout));
+      const itemId = await createItemExpectSuccess(Bob, collectionId, 'NFT');
+      //
+      const sendItem = api.tx.nft.transfer(Ferdie.address, collectionId, itemId, 1);
+      const burnItem = api.tx.nft.burnItem(collectionId, itemId, 1);
+      await Promise.all([
+        sendItem.signAndSend(Bob),
+        burnItem.signAndSend(Alice),
+      ]);
+      await timeoutPromise(10000);
+      let itemBurn = false;
+      itemBurn = (await (api.query.nft.nftItemList(collectionId, itemId))).toJSON() as boolean;
+      // tslint:disable-next-line: no-unused-expression
+      expect(itemBurn).to.be.null;
+      await timeoutPromise(20000);
+    });
+  });
+});

--- a/tests/src/collision-tests/adminDestroyCollection.test.ts
+++ b/tests/src/collision-tests/adminDestroyCollection.test.ts
@@ -1,35 +1,23 @@
 import { IKeyringPair } from '@polkadot/types/types';
-import BN from 'bn.js';
 import chai from 'chai';
 import chaiAsPromised from 'chai-as-promised';
 import privateKey from '../substrate/privateKey';
-import usingApi, { submitTransactionAsync, submitTransactionExpectFailAsync } from '../substrate/substrate-api';
+import usingApi, { submitTransactionAsync } from '../substrate/substrate-api';
 import {
   createCollectionExpectSuccess,
 } from '../util/helpers';
 
 chai.use(chaiAsPromised);
 const expect = chai.expect;
-interface ITokenDataType {
-  Owner: number[];
-  ConstData: number[];
-  VariableData: number[];
-}
 let Alice: IKeyringPair;
 let Bob: IKeyringPair;
 let Ferdie: IKeyringPair;
-let Charlie: IKeyringPair;
-let Eve: IKeyringPair;
-let Dave: IKeyringPair;
 
 before(async () => {
   await usingApi(async () => {
     Alice = privateKey('//Alice');
     Bob = privateKey('//Bob');
     Ferdie = privateKey('//Ferdie');
-    Charlie = privateKey('//Charlie');
-    Eve = privateKey('//Eve');
-    Dave = privateKey('//Dave');
   });
 });
 
@@ -45,13 +33,12 @@
       //
       const addWhitelistAdm = api.tx.nft.addToWhiteList(collectionId, Ferdie.address);
       const destroyCollection = api.tx.nft.destroyCollection(collectionId);
-      await Promise.all
-      ([
+      await Promise.all([
         addWhitelistAdm.signAndSend(Bob),
         destroyCollection.signAndSend(Alice),
       ]);
       await timeoutPromise(10000);
-      let whiteList: boolean = false;
+      let whiteList = false;
       whiteList = (await api.query.nft.whiteList(collectionId, Ferdie.address)).toJSON() as boolean;
       // tslint:disable-next-line: no-unused-expression
       expect(whiteList).to.be.false;

--- a/tests/src/collision-tests/adminLimitsOff.test.ts
+++ b/tests/src/collision-tests/adminLimitsOff.test.ts
@@ -10,11 +10,6 @@
 
 chai.use(chaiAsPromised);
 const expect = chai.expect;
-interface ITokenDataType {
-  Owner: number[];
-  ConstData: number[];
-  VariableData: number[];
-}
 let Alice: IKeyringPair;
 let Bob: IKeyringPair;
 let Ferdie: IKeyringPair;
@@ -51,11 +46,9 @@
       await submitTransactionAsync(Alice, changeAdminTx3);
 
       const timeoutPromise = (timeout: number) => new Promise((resolve) => setTimeout(resolve, timeout));
-      //
       const addAdmOne = api.tx.nft.addCollectionAdmin(collectionId, Ferdie.address);
       const addAdmTwo = api.tx.nft.addCollectionAdmin(collectionId, Charlie.address);
-      await Promise.all
-      ([
+      await Promise.all([
         addAdmOne.signAndSend(Bob),
         addAdmTwo.signAndSend(Alice),
       ]);

--- a/tests/src/collision-tests/adminRightsOff.test.ts
+++ b/tests/src/collision-tests/adminRightsOff.test.ts
@@ -3,33 +3,20 @@
 import chai from 'chai';
 import chaiAsPromised from 'chai-as-promised';
 import privateKey from '../substrate/privateKey';
-import usingApi, { submitTransactionAsync, submitTransactionExpectFailAsync } from '../substrate/substrate-api';
+import usingApi, { submitTransactionAsync } from '../substrate/substrate-api';
 import {
   createCollectionExpectSuccess,
 } from '../util/helpers';
 
 chai.use(chaiAsPromised);
 const expect = chai.expect;
-interface ITokenDataType {
-  Owner: number[];
-  ConstData: number[];
-  VariableData: number[];
-}
 let Alice: IKeyringPair;
 let Bob: IKeyringPair;
-let Ferdie: IKeyringPair;
-let Charlie: IKeyringPair;
-let Eve: IKeyringPair;
-let Dave: IKeyringPair;
 
 before(async () => {
   await usingApi(async () => {
     Alice = privateKey('//Alice');
     Bob = privateKey('//Bob');
-    Ferdie = privateKey('//Ferdie');
-    Charlie = privateKey('//Charlie');
-    Eve = privateKey('//Eve');
-    Dave = privateKey('//Dave');
   });
 });
 
@@ -42,12 +29,10 @@
       await submitTransactionAsync(Alice, changeAdminTx);
       const timeoutPromise = (timeout: number) => new Promise((resolve) => setTimeout(resolve, timeout));
       await timeoutPromise(10000);
-      //
       const args = [{ nft: ['0x31', '0x31'] }, { nft: ['0x32', '0x32'] }, { nft: ['0x33', '0x33'] }];
       const addItemAdm = api.tx.nft.createMultipleItems(collectionId, Bob.address, args);
       const removeAdm = api.tx.nft.removeCollectionAdmin(collectionId, Bob.address);
-      await Promise.all
-      ([
+      await Promise.all([
         addItemAdm.signAndSend(Bob),
         removeAdm.signAndSend(Alice),
       ]);

--- a/tests/src/collision-tests/setSponsorNewOwner.test.ts
+++ b/tests/src/collision-tests/setSponsorNewOwner.test.ts
@@ -1,20 +1,14 @@
 import { IKeyringPair } from '@polkadot/types/types';
-import BN from 'bn.js';
 import chai from 'chai';
 import chaiAsPromised from 'chai-as-promised';
 import privateKey from '../substrate/privateKey';
-import usingApi, { submitTransactionAsync, submitTransactionExpectFailAsync } from '../substrate/substrate-api';
+import usingApi from '../substrate/substrate-api';
 import {
-  createCollectionExpectSuccess, createItemExpectSuccess, setCollectionSponsorExpectSuccess,
+  createCollectionExpectSuccess, setCollectionSponsorExpectSuccess,
 } from '../util/helpers';
 
 chai.use(chaiAsPromised);
 const expect = chai.expect;
-interface ITokenDataType {
-  Owner: number[];
-  ConstData: number[];
-  VariableData: number[];
-}
 let Alice: IKeyringPair;
 let Bob: IKeyringPair;
 let Ferdie: IKeyringPair;
@@ -35,11 +29,9 @@
       await setCollectionSponsorExpectSuccess(collectionId, Bob.address);
       const timeoutPromise = (timeout: number) => new Promise((resolve) => setTimeout(resolve, timeout));
       await timeoutPromise(10000);
-      //
       const confirmSponsorship = api.tx.nft.confirmSponsorship(collectionId);
       const changeCollectionOwner = api.tx.nft.changeCollectionOwner(collectionId, Ferdie.address);
-      await Promise.all
-      ([
+      await Promise.all([
         confirmSponsorship.signAndSend(Bob),
         changeCollectionOwner.signAndSend(Alice),
       ]);

--- a/tests/src/collision-tests/sponsorPayments.test.ts
+++ b/tests/src/collision-tests/sponsorPayments.test.ts
@@ -1,58 +1,54 @@
-import { IKeyringPair } from '@polkadot/types/types';
-import chai from 'chai';
-import chaiAsPromised from 'chai-as-promised';
-import { alicesPublicKey, bobsPublicKey } from '../accounts';
-import getBalance from '../substrate/get-balance';
-import privateKey from '../substrate/privateKey';
-import usingApi, { submitTransactionAsync } from '../substrate/substrate-api';
-import waitNewBlocks from '../substrate/wait-new-blocks';
-import {
-  confirmSponsorshipExpectSuccess,
-  createCollectionExpectSuccess,
-  createItemExpectSuccess,
-  setCollectionSponsorExpectSuccess,
-} from '../util/helpers';
-
-chai.use(chaiAsPromised);
-const expect = chai.expect;
-let Alice: IKeyringPair;
-let Bob: IKeyringPair;
-let Ferdie: IKeyringPair;
-
-before(async () => {
-  await usingApi(async () => {
-    Alice = privateKey('//Alice');
-    Bob = privateKey('//Bob');
-    Ferdie = privateKey('//Ferdie');
-  });
-});
-
-describe('Payment of commission if one block: ', () => {
-  // tslint:disable-next-line: max-line-length
-  it('Payment of commission if one block contains transactions for payment from the sponsor\'s balance and his (sponsor\'s) exclusion from the collection ', async () => {
-    await usingApi(async (api) => {
-      const collectionId = await createCollectionExpectSuccess();
-      const changeAdminTxBob = api.tx.nft.addCollectionAdmin(collectionId, Bob.address);
-      await submitTransactionAsync(Alice, changeAdminTxBob);
-      const timeoutPromise = (timeout: number) => new Promise((resolve) => setTimeout(resolve, timeout));
-      const itemId = await createItemExpectSuccess(Bob, collectionId, 'NFT');
-      await setCollectionSponsorExpectSuccess(collectionId, Bob.address);
-      await confirmSponsorshipExpectSuccess(collectionId, '//Bob');
-      //
-      const [alicesBalanceBefore, bobsBalanceBefore] = await getBalance(api, [alicesPublicKey, bobsPublicKey]);
-      const sendItem = api.tx.nft.transfer(Alice.address, collectionId, itemId, 1);
-      const revokeSponsor = api.tx.nft.removeCollectionSponsor(collectionId);
-      await Promise.all
-      ([
-        sendItem.signAndSend(Bob),
-        revokeSponsor.signAndSend(Alice),
-      ]);
-      const [alicesBalanceAfter, bobsBalanceAfter] = await getBalance(api, [alicesPublicKey, bobsPublicKey]);
-      // tslint:disable-next-line:no-unused-expression
-      expect(alicesBalanceAfter === alicesBalanceBefore).to.be.true;
-      // tslint:disable-next-line:no-unused-expression
-      expect(bobsBalanceAfter === bobsBalanceBefore).to.be.true;
-      await timeoutPromise(20000);
-    });
-  });
-});
+import { IKeyringPair } from '@polkadot/types/types';
+import chai from 'chai';
+import chaiAsPromised from 'chai-as-promised';
+import { alicesPublicKey, bobsPublicKey } from '../accounts';
+import getBalance from '../substrate/get-balance';
+import privateKey from '../substrate/privateKey';
+import usingApi, { submitTransactionAsync } from '../substrate/substrate-api';
+import {
+  confirmSponsorshipExpectSuccess,
+  createCollectionExpectSuccess,
+  createItemExpectSuccess,
+  setCollectionSponsorExpectSuccess,
+} from '../util/helpers';
+
+chai.use(chaiAsPromised);
+const expect = chai.expect;
+let Alice: IKeyringPair;
+let Bob: IKeyringPair;
+
+before(async () => {
+  await usingApi(async () => {
+    Alice = privateKey('//Alice');
+    Bob = privateKey('//Bob');
+  });
+});
+
+describe('Payment of commission if one block: ', () => {
+  // tslint:disable-next-line: max-line-length
+  it('Payment of commission if one block contains transactions for payment from the sponsor\'s balance and his (sponsor\'s) exclusion from the collection ', async () => {
+    await usingApi(async (api) => {
+      const collectionId = await createCollectionExpectSuccess();
+      const changeAdminTxBob = api.tx.nft.addCollectionAdmin(collectionId, Bob.address);
+      await submitTransactionAsync(Alice, changeAdminTxBob);
+      const timeoutPromise = (timeout: number) => new Promise((resolve) => setTimeout(resolve, timeout));
+      const itemId = await createItemExpectSuccess(Bob, collectionId, 'NFT');
+      await setCollectionSponsorExpectSuccess(collectionId, Bob.address);
+      await confirmSponsorshipExpectSuccess(collectionId, '//Bob');
+
+      const [alicesBalanceBefore, bobsBalanceBefore] = await getBalance(api, [alicesPublicKey, bobsPublicKey]);
+      const sendItem = api.tx.nft.transfer(Alice.address, collectionId, itemId, 1);
+      const revokeSponsor = api.tx.nft.removeCollectionSponsor(collectionId);
+      await Promise.all([
+        sendItem.signAndSend(Bob),
+        revokeSponsor.signAndSend(Alice),
+      ]);
+      const [alicesBalanceAfter, bobsBalanceAfter] = await getBalance(api, [alicesPublicKey, bobsPublicKey]);
+      // tslint:disable-next-line:no-unused-expression
+      expect(alicesBalanceAfter === alicesBalanceBefore).to.be.true;
+      // tslint:disable-next-line:no-unused-expression
+      expect(bobsBalanceAfter === bobsBalanceBefore).to.be.true;
+      await timeoutPromise(20000);
+    });
+  });
+});

--- a/tests/src/collision-tests/tokenLimitsOff.test.ts
+++ b/tests/src/collision-tests/tokenLimitsOff.test.ts
@@ -13,11 +13,6 @@
 
 chai.use(chaiAsPromised);
 const expect = chai.expect;
-interface ITokenDataType {
-  Owner: number[];
-  ConstData: number[];
-  VariableData: number[];
-}
 let Alice: IKeyringPair;
 let Bob: IKeyringPair;
 let Ferdie: IKeyringPair;
@@ -63,14 +58,13 @@
       expect(subTxTesult.success).to.be.true;
       const timeoutPromise = (timeout: number) => new Promise((resolve) => setTimeout(resolve, timeout));
       await timeoutPromise(10000);
-      //
+
       const args = [{ nft: ['0x31', '0x31'] }, { nft: ['0x32', '0x32'] }, { nft: ['0x33', '0x33'] }];
       const mintItemOne = api.tx.nft
         .createMultipleItems(collectionId, Ferdie.address, args);
       const mintItemTwo = api.tx.nft
         .createMultipleItems(collectionId, Bob.address, args);
-      await Promise.all
-      ([
+      await Promise.all([
         mintItemOne.signAndSend(Ferdie),
         mintItemTwo.signAndSend(Bob),
       ]);

--- a/tests/src/collision-tests/turnsOffMinting.test.ts
+++ b/tests/src/collision-tests/turnsOffMinting.test.ts
@@ -1,50 +1,46 @@
-import { IKeyringPair } from '@polkadot/types/types';
-import chai from 'chai';
-import chaiAsPromised from 'chai-as-promised';
-import privateKey from '../substrate/privateKey';
-import usingApi, { submitTransactionAsync } from '../substrate/substrate-api';
-import waitNewBlocks from '../substrate/wait-new-blocks';
-import {
-  addToWhiteListExpectSuccess,
-  createCollectionExpectSuccess,
-  setMintPermissionExpectSuccess,
-} from '../util/helpers';
-
-chai.use(chaiAsPromised);
-const expect = chai.expect;
-let Alice: IKeyringPair;
-let Bob: IKeyringPair;
-let Ferdie: IKeyringPair;
-
-before(async () => {
-  await usingApi(async () => {
-    Alice = privateKey('//Alice');
-    Bob = privateKey('//Bob');
-    Ferdie = privateKey('//Ferdie');
-  });
-});
-
-describe('Turns off minting mode: ', () => {
-  // tslint:disable-next-line: max-line-length
-  it('The collection owner turns off minting mode and there are minting transactions in the same block ', async () => {
-    await usingApi(async (api) => {
-      const collectionId = await createCollectionExpectSuccess();
-      const timeoutPromise = (timeout: number) => new Promise((resolve) => setTimeout(resolve, timeout));
-      await setMintPermissionExpectSuccess(Alice, collectionId, true);
-      await addToWhiteListExpectSuccess(Alice, collectionId, Ferdie.address);
-      //
-      const mintItem = api.tx.nft.createItem(collectionId, Ferdie.address, 'NFT');
-      const offMinting = api.tx.nft.setMintPermission(collectionId, false);
-      await Promise.all
-      ([
-        mintItem.signAndSend(Ferdie),
-        offMinting.signAndSend(Alice),
-      ]);
-      let itemList: boolean = false;
-      itemList = (await (api.query.nft.nftItemList(collectionId, mintItem))).toJSON() as boolean;
-      // tslint:disable-next-line: no-unused-expression
-      expect(itemList).to.be.null;
-      await timeoutPromise(20000);
-    });
-  });
-});
+import { IKeyringPair } from '@polkadot/types/types';
+import chai from 'chai';
+import chaiAsPromised from 'chai-as-promised';
+import privateKey from '../substrate/privateKey';
+import usingApi from '../substrate/substrate-api';
+import {
+  addToWhiteListExpectSuccess,
+  createCollectionExpectSuccess,
+  setMintPermissionExpectSuccess,
+} from '../util/helpers';
+
+chai.use(chaiAsPromised);
+const expect = chai.expect;
+let Alice: IKeyringPair;
+let Ferdie: IKeyringPair;
+
+before(async () => {
+  await usingApi(async () => {
+    Alice = privateKey('//Alice');
+    Ferdie = privateKey('//Ferdie');
+  });
+});
+
+describe('Turns off minting mode: ', () => {
+  // tslint:disable-next-line: max-line-length
+  it('The collection owner turns off minting mode and there are minting transactions in the same block ', async () => {
+    await usingApi(async (api) => {
+      const collectionId = await createCollectionExpectSuccess();
+      const timeoutPromise = (timeout: number) => new Promise((resolve) => setTimeout(resolve, timeout));
+      await setMintPermissionExpectSuccess(Alice, collectionId, true);
+      await addToWhiteListExpectSuccess(Alice, collectionId, Ferdie.address);
+
+      const mintItem = api.tx.nft.createItem(collectionId, Ferdie.address, 'NFT');
+      const offMinting = api.tx.nft.setMintPermission(collectionId, false);
+      await Promise.all([
+        mintItem.signAndSend(Ferdie),
+        offMinting.signAndSend(Alice),
+      ]);
+      let itemList = false;
+      itemList = (await (api.query.nft.nftItemList(collectionId, mintItem))).toJSON() as boolean;
+      // tslint:disable-next-line: no-unused-expression
+      expect(itemList).to.be.null;
+      await timeoutPromise(20000);
+    });
+  });
+});

--- a/tests/src/config.ts
+++ b/tests/src/config.ts
@@ -6,7 +6,7 @@
 import process from 'process';
 
 const config = {
-  substrateUrl: process.env.substrateUrl || 'ws://127.0.0.1:9844'
-}
+  substrateUrl: process.env.substrateUrl || 'ws://127.0.0.1:9844',
+};
 
 export default config;
\ No newline at end of file

--- a/tests/src/config_docker.ts
+++ b/tests/src/config_docker.ts
@@ -6,7 +6,7 @@
 import process from 'process';
 
 const config = {
-  substrateUrl: process.env.substrateUrl || 'ws://172.17.0.1:9944'
-}
+  substrateUrl: process.env.substrateUrl || 'ws://172.17.0.1:9944',
+};
 
 export default config;
\ No newline at end of file

--- a/tests/src/confirmSponsorship.test.ts
+++ b/tests/src/confirmSponsorship.test.ts
@@ -5,12 +5,11 @@
 
 import chai from 'chai';
 import chaiAsPromised from 'chai-as-promised';
-import { default as usingApi, submitTransactionAsync, submitTransactionExpectFailAsync } from "./substrate/substrate-api";
+import { default as usingApi, submitTransactionAsync, submitTransactionExpectFailAsync } from './substrate/substrate-api';
 import { 
   createCollectionExpectSuccess, 
   setCollectionSponsorExpectSuccess, 
   destroyCollectionExpectSuccess, 
-  setCollectionSponsorExpectFailure,
   confirmSponsorshipExpectSuccess,
   confirmSponsorshipExpectFailure,
   createItemExpectSuccess,
@@ -20,10 +19,9 @@
   enablePublicMintingExpectSuccess,
   addToWhiteListExpectSuccess,
   normalizeAccountId,
-} from "./util/helpers";
-import { Keyring } from "@polkadot/api";
-import { IKeyringPair } from "@polkadot/types/types";
-import type { AccountId } from '@polkadot/types/interfaces';
+} from './util/helpers';
+import { Keyring } from '@polkadot/api';
+import { IKeyringPair } from '@polkadot/types/types';
 import { BigNumber } from 'bignumber.js';
 
 chai.use(chaiAsPromised);
@@ -36,11 +34,11 @@
 describe('integration test: ext. confirmSponsorship():', () => {
 
   before(async () => {
-    await usingApi(async (api) => {
+    await usingApi(async () => {
       const keyring = new Keyring({ type: 'sr25519' });
-      alice = keyring.addFromUri(`//Alice`);
-      bob = keyring.addFromUri(`//Bob`);
-      charlie = keyring.addFromUri(`//Charlie`);
+      alice = keyring.addFromUri('//Alice');
+      bob = keyring.addFromUri('//Bob');
+      charlie = keyring.addFromUri('//Charlie');
     });
   });
 
@@ -163,7 +161,7 @@
       await addToWhiteListExpectSuccess(alice, collectionId, zeroBalance.address);
 
       // Mint token using unused address as signer
-      const tokenId = await createItemExpectSuccess(zeroBalance, collectionId, 'NFT', zeroBalance.address);
+      await createItemExpectSuccess(zeroBalance, collectionId, 'NFT', zeroBalance.address);
 
       const BsponsorBalance = new BigNumber((await api.query.system.account(bob.address)).data.free.toString());
 
@@ -195,7 +193,7 @@
       const badTransaction = async function () { 
         await submitTransactionExpectFailAsync(zeroBalance, zeroToAlice);
       };
-      await expect(badTransaction()).to.be.rejectedWith("Inability to pay some fees");
+      await expect(badTransaction()).to.be.rejectedWith('Inability to pay some fees');
       const BsponsorBalance = new BigNumber((await api.query.system.account(bob.address)).data.free.toString());
 
       // Try again after Zero gets some balance - now it should succeed
@@ -228,11 +226,7 @@
       const result1 = getGenericResult(events1);
 
       const AsponsorBalance = new BigNumber((await api.query.system.account(bob.address)).data.free.toString());
-
-      const badTransaction = async function () { 
-        await submitTransactionExpectFailAsync(zeroBalance, zeroToAlice);
-      };
-
+      await submitTransactionExpectFailAsync(zeroBalance, zeroToAlice);
       const BsponsorBalance = new BigNumber((await api.query.system.account(bob.address)).data.free.toString());
 
       // Try again after Zero gets some balance - now it should succeed
@@ -271,7 +265,7 @@
       const badTransaction = async function () { 
         await submitTransactionExpectFailAsync(zeroBalance, zeroToAlice);
       };
-      await expect(badTransaction()).to.be.rejectedWith("Inability to pay some fees");
+      await expect(badTransaction()).to.be.rejectedWith('Inability to pay some fees');
       const BsponsorBalance = new BigNumber((await api.query.system.account(bob.address)).data.free.toString());
 
       // Try again after Zero gets some balance - now it should succeed
@@ -317,7 +311,7 @@
       const badTransaction = async function () { 
         await createItemExpectSuccess(zeroBalance, collectionId, 'NFT', zeroBalance.address);
       };
-      await expect(badTransaction()).to.be.rejectedWith("Inability to pay some fees");
+      await expect(badTransaction()).to.be.rejectedWith('Inability to pay some fees');
       console.error = consoleError;
       console.log = consoleLog;
       const BsponsorBalance = new BigNumber((await api.query.system.account(bob.address)).data.free.toString());
@@ -335,19 +329,19 @@
 
 describe('(!negative test!) integration test: ext. removeCollectionSponsor():', () => {
   before(async () => {
-    await usingApi(async (api) => {
+    await usingApi(async () => {
       const keyring = new Keyring({ type: 'sr25519' });
-      alice = keyring.addFromUri(`//Alice`);
-      bob = keyring.addFromUri(`//Bob`);
-      charlie = keyring.addFromUri(`//Charlie`);
+      alice = keyring.addFromUri('//Alice');
+      bob = keyring.addFromUri('//Bob');
+      charlie = keyring.addFromUri('//Charlie');
     });
   });
 
   it('(!negative test!) Confirm sponsorship for a collection that never existed', async () => {
     // Find the collection that never existed
-    const collectionId = 0;
+    let collectionId = 0;
     await usingApi(async (api) => {
-      const collectionId = parseInt((await api.query.nft.createdCollectionCount()).toString()) + 1;
+      collectionId = parseInt((await api.query.nft.createdCollectionCount()).toString()) + 1;
     });
 
     await confirmSponsorshipExpectFailure(collectionId, '//Bob');

--- a/tests/src/connection.test.ts
+++ b/tests/src/connection.test.ts
@@ -3,7 +3,7 @@
 // file 'LICENSE', which is part of this source code package.
 //
 
-import usingApi from "./substrate/substrate-api";
+import usingApi from './substrate/substrate-api';
 import { WsProvider } from '@polkadot/api';
 import * as chai from 'chai';
 import chaiAsPromised from 'chai-as-promised';
@@ -29,7 +29,7 @@
     const neverConnectProvider = new WsProvider('ws://255.255.255.255:9944');
     await expect((async () => {
       await usingApi(async api => {
-        const health = await api.rpc.system.health();
+        await api.rpc.system.health();
       }, { provider: neverConnectProvider });
     })()).to.be.eventually.rejected;
 

--- a/tests/src/contracts.test.ts
+++ b/tests/src/contracts.test.ts
@@ -3,17 +3,17 @@
 // file 'LICENSE', which is part of this source code package.
 //
 
-import chai from "chai";
+import chai from 'chai';
 import chaiAsPromised from 'chai-as-promised';
-import usingApi, { submitTransactionAsync, submitTransactionExpectFailAsync } from "./substrate/substrate-api";
-import fs from "fs";
-import { Abi, ContractPromise as Contract } from "@polkadot/api-contract";
-import privateKey from "./substrate/privateKey";
+import usingApi, { submitTransactionAsync } from './substrate/substrate-api';
+import fs from 'fs';
+import { Abi, ContractPromise as Contract } from '@polkadot/api-contract';
+import privateKey from './substrate/privateKey';
 import {
   deployFlipper,
   getFlipValue,
   deployTransferContract,
-} from "./util/contracthelpers";
+} from './util/contracthelpers';
 
 import {
   addToWhiteListExpectSuccess,
@@ -25,8 +25,8 @@
   getGenericResult,
   normalizeAccountId,
   isWhitelisted,
-  transferFromExpectSuccess
-} from "./util/helpers";
+  transferFromExpectSuccess,
+} from './util/helpers';
 
 
 chai.use(chaiAsPromised);
@@ -37,12 +37,12 @@
 const marketContractAddress = '5CYN9j3YvRkqxewoxeSvRbhAym4465C57uMmX5j4yz99L5H6';
 
 describe('Contracts', () => {
-  it(`Can deploy smart contract Flipper, instantiate it and call it's get and flip messages.`, async () => {
+  it('Can deploy smart contract Flipper, instantiate it and call it\'s get and flip messages.', async () => {
     await usingApi(async api => {
       const [contract, deployer] = await deployFlipper(api);
       const initialGetResponse = await getFlipValue(contract, deployer);
 
-      const bob = privateKey("//Bob");
+      const bob = privateKey('//Bob');
       const flip = contract.tx.flip(value, gasLimit);
       await submitTransactionAsync(bob, flip);
 
@@ -65,13 +65,13 @@
 describe.only('Chain extensions', () => {
   it('Transfer CE', async () => {
     await usingApi(async api => {
-      const alice = privateKey("//Alice");
-      const bob = privateKey("//Bob");
+      const alice = privateKey('//Alice');
+      const bob = privateKey('//Bob');
 
       // Prep work
       const collectionId = await createCollectionExpectSuccess();
       const tokenId = await createItemExpectSuccess(alice, collectionId, 'NFT');
-      const [contract, deployer] = await deployTransferContract(api);
+      const [contract] = await deployTransferContract(api);
       const changeAdminTx = api.tx.nft.addCollectionAdmin(collectionId, contract.address);
       await submitTransactionAsync(alice, changeAdminTx);
 
@@ -96,7 +96,7 @@
       const bob = privateKey('//Bob');
 
       const collectionId = await createCollectionExpectSuccess();
-      const [contract, deployer] = await deployTransferContract(api);
+      const [contract] = await deployTransferContract(api);
       await enablePublicMintingExpectSuccess(alice, collectionId);
       await enableWhiteListExpectSuccess(alice, collectionId);
       await addToWhiteListExpectSuccess(alice, collectionId, contract.address);
@@ -124,7 +124,7 @@
       const bob = privateKey('//Bob');
 
       const collectionId = await createCollectionExpectSuccess();
-      const [contract, deployer] = await deployTransferContract(api);
+      const [contract] = await deployTransferContract(api);
       await enablePublicMintingExpectSuccess(alice, collectionId);
       await enableWhiteListExpectSuccess(alice, collectionId);
       await addToWhiteListExpectSuccess(alice, collectionId, contract.address);
@@ -133,7 +133,7 @@
       const transferTx = contract.tx.createMultipleItems(value, gasLimit, bob.address, collectionId, [
         { Nft: { const_data: '0x010203', variable_data: '0x020304' } },
         { Nft: { const_data: '0x010204', variable_data: '0x020305' } },
-        { Nft: { const_data: '0x010205', variable_data: '0x020306' } }
+        { Nft: { const_data: '0x010205', variable_data: '0x020306' } },
       ]);
       const events = await submitTransactionAsync(alice, transferTx);
       const result = getGenericResult(events);
@@ -169,7 +169,7 @@
       const charlie = privateKey('//Charlie');
 
       const collectionId = await createCollectionExpectSuccess();
-      const [contract, deployer] = await deployTransferContract(api);
+      const [contract] = await deployTransferContract(api);
       const tokenId = await createItemExpectSuccess(alice, collectionId, 'NFT', contract.address.toString());
 
       const transferTx = contract.tx.approve(value, gasLimit, bob.address, collectionId, tokenId, 1);
@@ -188,7 +188,7 @@
       const charlie = privateKey('//Charlie');
 
       const collectionId = await createCollectionExpectSuccess();
-      const [contract, deployer] = await deployTransferContract(api);
+      const [contract] = await deployTransferContract(api);
       const tokenId = await createItemExpectSuccess(alice, collectionId, 'NFT', bob.address);
       await approveExpectSuccess(collectionId, tokenId, bob, contract.address.toString(), 1);
 
@@ -197,7 +197,7 @@
       const result = getGenericResult(events);
       expect(result.success).to.be.true;
 
-      const token: any = (await api.query.nft.nftItemList(collectionId, tokenId) as any).unwrap()
+      const token: any = (await api.query.nft.nftItemList(collectionId, tokenId) as any).unwrap();
       expect(token.Owner.toString()).to.be.equal(charlie.address);
     });
   });
@@ -207,7 +207,7 @@
       const alice = privateKey('//Alice');
 
       const collectionId = await createCollectionExpectSuccess();
-      const [contract, deployer] = await deployTransferContract(api);
+      const [contract] = await deployTransferContract(api);
       const tokenId = await createItemExpectSuccess(alice, collectionId, 'NFT', contract.address.toString());
 
       const transferTx = contract.tx.setVariableMetaData(value, gasLimit, collectionId, tokenId, '0x121314');
@@ -215,7 +215,7 @@
       const result = getGenericResult(events);
       expect(result.success).to.be.true;
 
-      const token: any = (await api.query.nft.nftItemList(collectionId, tokenId) as any).unwrap()
+      const token: any = (await api.query.nft.nftItemList(collectionId, tokenId) as any).unwrap();
       expect(token.VariableData.toString()).to.be.equal('0x121314');
     });
   });
@@ -226,7 +226,7 @@
       const bob = privateKey('//Bob');
 
       const collectionId = await createCollectionExpectSuccess();
-      const [contract, deployer] = await deployTransferContract(api);
+      const [contract] = await deployTransferContract(api);
       const changeAdminTx = api.tx.nft.addCollectionAdmin(collectionId, contract.address);
       await submitTransactionAsync(alice, changeAdminTx);      
 

--- a/tests/src/createItem.test.ts
+++ b/tests/src/createItem.test.ts
@@ -1,39 +1,39 @@
-//
-// This file is subject to the terms and conditions defined in
-// file 'LICENSE', which is part of this source code package.
-//
-
-import { default as usingApi } from './substrate/substrate-api';
-import { Keyring } from "@polkadot/api";
-import { IKeyringPair } from "@polkadot/types/types";
-import { 
-  createCollectionExpectSuccess, 
-  createItemExpectSuccess
-} from './util/helpers';
-
-let alice: IKeyringPair;
-
-describe('integration test: ext. createItem():', () => {
-  before(async () => {
-    await usingApi(async (api) => {
-      const keyring = new Keyring({ type: 'sr25519' });
-      alice = keyring.addFromUri(`//Alice`);
-    });
-  });
-
-  it('Create new item in NFT collection', async () => {
-    const createMode = 'NFT';
-    const newCollectionID = await createCollectionExpectSuccess({mode: {type: createMode}});
-    await createItemExpectSuccess(alice, newCollectionID, createMode);
-  });
-  it('Create new item in Fungible collection', async () => {
-    const createMode = 'Fungible';
-    const newCollectionID = await createCollectionExpectSuccess({mode: {type: createMode, decimalPoints: 0}});
-    await createItemExpectSuccess(alice, newCollectionID, createMode);
-  });
-  it('Create new item in ReFungible collection', async () => {
-    const createMode = 'ReFungible';
-    const newCollectionID = await createCollectionExpectSuccess({mode: {type: createMode}});
-    await createItemExpectSuccess(alice, newCollectionID, createMode);
-  });
-});
+//
+// This file is subject to the terms and conditions defined in
+// file 'LICENSE', which is part of this source code package.
+//
+
+import { default as usingApi } from './substrate/substrate-api';
+import { Keyring } from '@polkadot/api';
+import { IKeyringPair } from '@polkadot/types/types';
+import { 
+  createCollectionExpectSuccess, 
+  createItemExpectSuccess,
+} from './util/helpers';
+
+let alice: IKeyringPair;
+
+describe('integration test: ext. createItem():', () => {
+  before(async () => {
+    await usingApi(async () => {
+      const keyring = new Keyring({ type: 'sr25519' });
+      alice = keyring.addFromUri('//Alice');
+    });
+  });
+
+  it('Create new item in NFT collection', async () => {
+    const createMode = 'NFT';
+    const newCollectionID = await createCollectionExpectSuccess({mode: {type: createMode}});
+    await createItemExpectSuccess(alice, newCollectionID, createMode);
+  });
+  it('Create new item in Fungible collection', async () => {
+    const createMode = 'Fungible';
+    const newCollectionID = await createCollectionExpectSuccess({mode: {type: createMode, decimalPoints: 0}});
+    await createItemExpectSuccess(alice, newCollectionID, createMode);
+  });
+  it('Create new item in ReFungible collection', async () => {
+    const createMode = 'ReFungible';
+    const newCollectionID = await createCollectionExpectSuccess({mode: {type: createMode}});
+    await createItemExpectSuccess(alice, newCollectionID, createMode);
+  });
+});

--- a/tests/src/creditFeesToTreasury.test.ts
+++ b/tests/src/creditFeesToTreasury.test.ts
@@ -5,16 +5,16 @@
 
 import chai from 'chai';
 import chaiAsPromised from 'chai-as-promised';
-import { default as usingApi, submitTransactionAsync, submitTransactionExpectFailAsync } from "./substrate/substrate-api";
-import { alicesPublicKey, bobsPublicKey } from "./accounts";
-import privateKey from "./substrate/privateKey";
+import { default as usingApi, submitTransactionAsync, submitTransactionExpectFailAsync } from './substrate/substrate-api';
+import { alicesPublicKey, bobsPublicKey } from './accounts';
+import privateKey from './substrate/privateKey';
 import { BigNumber } from 'bignumber.js';
 import { IKeyringPair } from '@polkadot/types/types';
 import { 
   createCollectionExpectSuccess, 
   createItemExpectSuccess,
   getGenericResult,
-  transferExpectSuccess
+  transferExpectSuccess,
 } from './util/helpers';
 
 import { default as waitNewBlocks } from './substrate/wait-new-blocks';
@@ -23,7 +23,7 @@
 chai.use(chaiAsPromised);
 const expect = chai.expect;
 
-const Treasury = "5EYCAe5ijiYfyeZ2JJCGq56LmPyNRAKzpG4QkoQkkQNB5e6Z";
+const Treasury = '5EYCAe5ijiYfyeZ2JJCGq56LmPyNRAKzpG4QkoQkkQNB5e6Z';
 const saneMinimumFee = 0.05;
 const saneMaximumFee = 0.5;
 const createCollectionDeposit = 100;
@@ -33,8 +33,9 @@
 
 // Skip the inflation block pauses if the block is close to inflation block 
 // until the inflation happens
+/*eslint no-async-promise-executor: "off"*/
 function skipInflationBlock(api: ApiPromise): Promise<void> {
-  const promise = new Promise<void>(async (resolve, reject) => {
+  const promise = new Promise<void>(async (resolve) => {
     const blockInterval = parseInt((await api.consts.inflation.inflationBlockInterval).toString());
     const unsubscribe = await api.rpc.chain.subscribeNewHeads(head => {
       const currentBlock = parseInt(head.number.toString());
@@ -52,7 +53,7 @@
 
 describe('integration test: Fees must be credited to Treasury:', () => {
   before(async () => {
-    await usingApi(async (api) => {
+    await usingApi(async () => {
       alice = privateKey('//Alice');
       bob = privateKey('//Bob');
     });

--- a/tests/src/destroyCollection.test.ts
+++ b/tests/src/destroyCollection.test.ts
@@ -7,8 +7,8 @@
 import chai from 'chai';
 import chaiAsPromised from 'chai-as-promised';
 import privateKey from './substrate/privateKey';
-import { default as usingApi } from "./substrate/substrate-api";
-import { createCollectionExpectSuccess, destroyCollectionExpectSuccess, destroyCollectionExpectFailure, setCollectionLimitsExpectSuccess } from "./util/helpers";
+import { default as usingApi } from './substrate/substrate-api';
+import { createCollectionExpectSuccess, destroyCollectionExpectSuccess, destroyCollectionExpectFailure, setCollectionLimitsExpectSuccess } from './util/helpers';
 
 chai.use(chaiAsPromised);
 
@@ -31,7 +31,7 @@
   let alice: IKeyringPair;
 
   before(async () => {
-    await usingApi(async (api) => {
+    await usingApi(async () => {
       alice = privateKey('//Alice');
     });
   });

--- a/tests/src/enableContractSponsoring.test.ts
+++ b/tests/src/enableContractSponsoring.test.ts
@@ -81,7 +81,7 @@
 
   it('fails when called by non-owning user', async () => {
     await usingApi(async (api) => {
-      const [flipper, _] = await deployFlipper(api);
+      const [flipper] = await deployFlipper(api);
 
       await enableContractSponsoringExpectFailure(alice, flipper.address, true);
     });

--- a/tests/src/eth/fungible.test.ts
+++ b/tests/src/eth/fungible.test.ts
@@ -1,289 +1,294 @@
-import privateKey from "../substrate/privateKey";
-import { approveExpectSuccess, createCollectionExpectSuccess, createFungibleItemExpectSuccess, transferExpectSuccess, transferFromExpectSuccess } from "../util/helpers";
-import { collectionIdToAddress, createEthAccount, itWeb3, normalizeEvents, recordEvents, subToEth, transferBalanceToEth } from "./util/helpers"
+//
+// This file is subject to the terms and conditions defined in
+// file 'LICENSE', which is part of this source code package.
+//
+
+import privateKey from '../substrate/privateKey';
+import { approveExpectSuccess, createCollectionExpectSuccess, createFungibleItemExpectSuccess, transferExpectSuccess, transferFromExpectSuccess } from '../util/helpers';
+import { collectionIdToAddress, createEthAccount, itWeb3, normalizeEvents, recordEvents, subToEth, transferBalanceToEth } from './util/helpers';
 import fungibleAbi from './fungibleAbi.json';
-import { expect } from "chai";
+import { expect } from 'chai';
 
 describe('Information getting', () => {
-    itWeb3('totalSupply', async ({ web3 }) => {
-        const collection = await createCollectionExpectSuccess({
-            name: 'token name',
-            mode: { type: 'Fungible', decimalPoints: 0 }
-        });
-        const alice = privateKey('//Alice');
+  itWeb3('totalSupply', async ({ web3 }) => {
+    const collection = await createCollectionExpectSuccess({
+      name: 'token name',
+      mode: { type: 'Fungible', decimalPoints: 0 },
+    });
+    const alice = privateKey('//Alice');
 
-        await createFungibleItemExpectSuccess(alice, collection, { Value: 200n }, { substrate: alice.address });
+    await createFungibleItemExpectSuccess(alice, collection, { Value: 200n }, { substrate: alice.address });
 
-        const address = collectionIdToAddress(collection);
-        const contract = new web3.eth.Contract(fungibleAbi as any, address);
-        const totalSupply = await contract.methods.totalSupply().call();
+    const address = collectionIdToAddress(collection);
+    const contract = new web3.eth.Contract(fungibleAbi as any, address);
+    const totalSupply = await contract.methods.totalSupply().call();
+
+    // FIXME: always equals to 0, because this method is not implemented
+    expect(totalSupply).to.equal('0');
+  });
 
-        // FIXME: always equals to 0, because this method is not implemented
-        expect(totalSupply).to.equal('0');
+  itWeb3('balanceOf', async ({ web3 }) => {
+    const collection = await createCollectionExpectSuccess({
+      name: 'token name',
+      mode: { type: 'Fungible', decimalPoints: 0 },
     });
+    const alice = privateKey('//Alice');
 
-    itWeb3('balanceOf', async ({ web3 }) => {
-        const collection = await createCollectionExpectSuccess({
-            name: 'token name',
-            mode: { type: 'Fungible', decimalPoints: 0 }
-        });
-        const alice = privateKey('//Alice');
+    const caller = createEthAccount(web3);
+    await createFungibleItemExpectSuccess(alice, collection, { Value: 200n }, { ethereum: caller });
 
-        const caller = createEthAccount(web3);
-        await createFungibleItemExpectSuccess(alice, collection, { Value: 200n }, { ethereum: caller });
+    const address = collectionIdToAddress(collection);
+    const contract = new web3.eth.Contract(fungibleAbi as any, address);
+    const balance = await contract.methods.balanceOf(caller).call();
 
-        const address = collectionIdToAddress(collection);
-        const contract = new web3.eth.Contract(fungibleAbi as any, address);
-        const balance = await contract.methods.balanceOf(caller).call();
-
-        expect(balance).to.equal('200');
-    });
+    expect(balance).to.equal('200');
+  });
 });
 
 describe('Plain calls', () => {
-    itWeb3('Can perform approve()', async ({ web3, api }) => {
-        const collection = await createCollectionExpectSuccess({
-            name: 'token name',
-            mode: { type: 'Fungible', decimalPoints: 0 }
-        });
-        const alice = privateKey('//Alice');
+  itWeb3('Can perform approve()', async ({ web3, api }) => {
+    const collection = await createCollectionExpectSuccess({
+      name: 'token name',
+      mode: { type: 'Fungible', decimalPoints: 0 },
+    });
+    const alice = privateKey('//Alice');
 
-        const owner = createEthAccount(web3);
-        await transferBalanceToEth(api, alice, owner, 999999999999999);
+    const owner = createEthAccount(web3);
+    await transferBalanceToEth(api, alice, owner, 999999999999999);
 
-        await createFungibleItemExpectSuccess(alice, collection, { Value: 200n }, { ethereum: owner });
+    await createFungibleItemExpectSuccess(alice, collection, { Value: 200n }, { ethereum: owner });
 
-        const spender = createEthAccount(web3);
+    const spender = createEthAccount(web3);
 
-        const address = collectionIdToAddress(collection);
-        const contract = new web3.eth.Contract(fungibleAbi as any, address);
+    const address = collectionIdToAddress(collection);
+    const contract = new web3.eth.Contract(fungibleAbi as any, address);
+
+    {
+      const result = await contract.methods.approve(spender, 100).send({ from: owner, gas: '0x1000000', gasPrice: '0x01' });
+      const events = normalizeEvents(result.events);
 
+      expect(events).to.be.deep.equal([
         {
-            const result = await contract.methods.approve(spender, 100).send({ from: owner, gas: '0x1000000', gasPrice: '0x01' });
-            const events = normalizeEvents(result.events);
+          address,
+          event: 'Approval',
+          args: {
+            owner,
+            spender,
+            value: '100',
+          },
+        },
+      ]);
+    }
 
-            expect(events).to.be.deep.equal([
-                {
-                    address,
-                    event: 'Approval',
-                    args: {
-                        owner,
-                        spender,
-                        value: '100',
-                    }
-                }
-            ]);
-        }
+    {
+      const allowance = await contract.methods.allowance(owner, spender).call();
+      expect(+allowance).to.equal(100);
+    }
+  });
 
-        {
-            const allowance = await contract.methods.allowance(owner, spender).call();
-            expect(+allowance).to.equal(100);
-        }
+  itWeb3('Can perform transferFrom()', async ({ web3, api }) => {
+    const collection = await createCollectionExpectSuccess({
+      name: 'token name',
+      mode: { type: 'Fungible', decimalPoints: 0 },
     });
+    const alice = privateKey('//Alice');
 
-    itWeb3('Can perform transferFrom()', async ({ web3, api }) => {
-        const collection = await createCollectionExpectSuccess({
-            name: 'token name',
-            mode: { type: 'Fungible', decimalPoints: 0 }
-        });
-        const alice = privateKey('//Alice');
-
-        const owner = createEthAccount(web3);
-        await transferBalanceToEth(api, alice, owner, 999999999999999);
+    const owner = createEthAccount(web3);
+    await transferBalanceToEth(api, alice, owner, 999999999999999);
 
-        await createFungibleItemExpectSuccess(alice, collection, { Value: 200n }, { ethereum: owner });
+    await createFungibleItemExpectSuccess(alice, collection, { Value: 200n }, { ethereum: owner });
 
-        const spender = createEthAccount(web3);
-        await transferBalanceToEth(api, alice, spender, 999999999999999);
+    const spender = createEthAccount(web3);
+    await transferBalanceToEth(api, alice, spender, 999999999999999);
 
-        const receiver = createEthAccount(web3);
+    const receiver = createEthAccount(web3);
 
-        const address = collectionIdToAddress(collection);
-        const contract = new web3.eth.Contract(fungibleAbi as any, address);
+    const address = collectionIdToAddress(collection);
+    const contract = new web3.eth.Contract(fungibleAbi as any, address);
 
-        await contract.methods.approve(spender, 100).send({ from: owner, gas: '0x1000000', gasPrice: '0x01' });
+    await contract.methods.approve(spender, 100).send({ from: owner, gas: '0x1000000', gasPrice: '0x01' });
 
+    {
+      const result = await contract.methods.transferFrom(owner, receiver, 49).send({ from: spender, gas: '0x1000000', gasPrice: '0x01' });
+      const events = normalizeEvents(result.events);
+      expect(events).to.be.deep.equal([
         {
-            const result = await contract.methods.transferFrom(owner, receiver, 49).send({ from: spender, gas: '0x1000000', gasPrice: '0x01' });
-            const events = normalizeEvents(result.events);
-            expect(events).to.be.deep.equal([
-                {
-                    address,
-                    event: 'Transfer',
-                    args: {
-                        from: owner,
-                        to: receiver,
-                        value: '49',
-                    }
-                },
-                {
-                    address,
-                    event: 'Approval',
-                    args: {
-                        owner,
-                        spender,
-                        value: '51',
-                    }
-                }
-            ]);
-        }
-
+          address,
+          event: 'Transfer',
+          args: {
+            from: owner,
+            to: receiver,
+            value: '49',
+          },
+        },
         {
-            const balance = await contract.methods.balanceOf(receiver).call();
-            expect(+balance).to.equal(49);
-        }
+          address,
+          event: 'Approval',
+          args: {
+            owner,
+            spender,
+            value: '51',
+          },
+        },
+      ]);
+    }
 
-        {
-            const balance = await contract.methods.balanceOf(owner).call();
-            expect(+balance).to.equal(151);
-        }
-    });
+    {
+      const balance = await contract.methods.balanceOf(receiver).call();
+      expect(+balance).to.equal(49);
+    }
 
-    itWeb3('Can perform transfer()', async ({ web3, api }) => {
-        const collection = await createCollectionExpectSuccess({
-            name: 'token name',
-            mode: { type: 'Fungible', decimalPoints: 0 }
-        });
-        const alice = privateKey('//Alice');
+    {
+      const balance = await contract.methods.balanceOf(owner).call();
+      expect(+balance).to.equal(151);
+    }
+  });
 
-        const owner = createEthAccount(web3);
-        await transferBalanceToEth(api, alice, owner, 999999999999999);
+  itWeb3('Can perform transfer()', async ({ web3, api }) => {
+    const collection = await createCollectionExpectSuccess({
+      name: 'token name',
+      mode: { type: 'Fungible', decimalPoints: 0 },
+    });
+    const alice = privateKey('//Alice');
 
-        await createFungibleItemExpectSuccess(alice, collection, { Value: 200n }, { ethereum: owner });
+    const owner = createEthAccount(web3);
+    await transferBalanceToEth(api, alice, owner, 999999999999999);
 
-        const receiver = createEthAccount(web3);
-        await transferBalanceToEth(api, alice, receiver, 999999999999999);
+    await createFungibleItemExpectSuccess(alice, collection, { Value: 200n }, { ethereum: owner });
 
-        const address = collectionIdToAddress(collection);
-        const contract = new web3.eth.Contract(fungibleAbi as any, address);
+    const receiver = createEthAccount(web3);
+    await transferBalanceToEth(api, alice, receiver, 999999999999999);
 
-        {
-            const result = await contract.methods.transfer(receiver, 50).send({ from: owner, gas: '0x1000000', gasPrice: '0x01' });
-            const events = normalizeEvents(result.events);
-            expect(events).to.be.deep.equal([
-                {
-                    address,
-                    event: 'Transfer',
-                    args: {
-                        from: owner,
-                        to: receiver,
-                        value: '50',
-                    }
-                },
-            ])
-        }
+    const address = collectionIdToAddress(collection);
+    const contract = new web3.eth.Contract(fungibleAbi as any, address);
 
+    {
+      const result = await contract.methods.transfer(receiver, 50).send({ from: owner, gas: '0x1000000', gasPrice: '0x01' });
+      const events = normalizeEvents(result.events);
+      expect(events).to.be.deep.equal([
         {
-            const balance = await contract.methods.balanceOf(owner).call();
-            expect(+balance).to.equal(150);
-        }
+          address,
+          event: 'Transfer',
+          args: {
+            from: owner,
+            to: receiver,
+            value: '50',
+          },
+        },
+      ]);
+    }
+
+    {
+      const balance = await contract.methods.balanceOf(owner).call();
+      expect(+balance).to.equal(150);
+    }
 
-        {
-            const balance = await contract.methods.balanceOf(receiver).call();
-            expect(+balance).to.equal(50);
-        }
-    });
+    {
+      const balance = await contract.methods.balanceOf(receiver).call();
+      expect(+balance).to.equal(50);
+    }
+  });
 });
 
 describe('Substrate calls', () => {
-    itWeb3('Events emitted for approve()', async ({ web3 }) => {
-        const collection = await createCollectionExpectSuccess({
-            mode: { type: 'Fungible', decimalPoints: 0 }
-        });
-        const alice = privateKey('//Alice');
-
-        const receiver = createEthAccount(web3);
+  itWeb3('Events emitted for approve()', async ({ web3 }) => {
+    const collection = await createCollectionExpectSuccess({
+      mode: { type: 'Fungible', decimalPoints: 0 },
+    });
+    const alice = privateKey('//Alice');
 
-        await createFungibleItemExpectSuccess(alice, collection, { Value: 200n });
+    const receiver = createEthAccount(web3);
 
-        const address = collectionIdToAddress(collection);
-        const contract = new web3.eth.Contract(fungibleAbi as any, address);
+    await createFungibleItemExpectSuccess(alice, collection, { Value: 200n });
 
-        const events = await recordEvents(contract, async () => {
-            await approveExpectSuccess(collection, 1, alice, { ethereum: receiver }, 100);
-        });
+    const address = collectionIdToAddress(collection);
+    const contract = new web3.eth.Contract(fungibleAbi as any, address);
 
-        expect(events).to.be.deep.equal([
-            {
-                address,
-                event: 'Approval',
-                args: {
-                    owner: subToEth(alice.address),
-                    spender: receiver,
-                    value: '100',
-                }
-            }
-        ]);
+    const events = await recordEvents(contract, async () => {
+      await approveExpectSuccess(collection, 1, alice, { ethereum: receiver }, 100);
     });
 
-    itWeb3('Events emitted for transferFrom()', async ({ web3 }) => {
-        const collection = await createCollectionExpectSuccess({
-            mode: { type: 'Fungible', decimalPoints: 0 }
-        });
-        const alice = privateKey('//Alice');
-        const bob = privateKey('//Bob');
+    expect(events).to.be.deep.equal([
+      {
+        address,
+        event: 'Approval',
+        args: {
+          owner: subToEth(alice.address),
+          spender: receiver,
+          value: '100',
+        },
+      },
+    ]);
+  });
 
-        const receiver = createEthAccount(web3);
+  itWeb3('Events emitted for transferFrom()', async ({ web3 }) => {
+    const collection = await createCollectionExpectSuccess({
+      mode: { type: 'Fungible', decimalPoints: 0 },
+    });
+    const alice = privateKey('//Alice');
+    const bob = privateKey('//Bob');
 
-        await createFungibleItemExpectSuccess(alice, collection, { Value: 200n });
-        await approveExpectSuccess(collection, 1, alice, bob, 100);
+    const receiver = createEthAccount(web3);
 
-        const address = collectionIdToAddress(collection);
-        const contract = new web3.eth.Contract(fungibleAbi as any, address);
+    await createFungibleItemExpectSuccess(alice, collection, { Value: 200n });
+    await approveExpectSuccess(collection, 1, alice, bob, 100);
 
-        const events = await recordEvents(contract, async () => {
-            await transferFromExpectSuccess(collection, 1, bob, alice, { ethereum: receiver }, 51, 'Fungible');
-        });
+    const address = collectionIdToAddress(collection);
+    const contract = new web3.eth.Contract(fungibleAbi as any, address);
 
-        expect(events).to.be.deep.equal([
-            {
-                address,
-                event: 'Transfer',
-                args: {
-                    from: subToEth(alice.address),
-                    to: receiver,
-                    value: '51',
-                }
-            },
-            {
-                address,
-                event: 'Approval',
-                args: {
-                    owner: subToEth(alice.address),
-                    spender: subToEth(bob.address),
-                    value: '49',
-                }
-            }
-        ]);
+    const events = await recordEvents(contract, async () => {
+      await transferFromExpectSuccess(collection, 1, bob, alice, { ethereum: receiver }, 51, 'Fungible');
     });
 
-    itWeb3('Events emitted for transfer()', async ({ web3 }) => {
-        const collection = await createCollectionExpectSuccess({
-            mode: { type: 'Fungible', decimalPoints: 0 }
-        });
-        const alice = privateKey('//Alice');
+    expect(events).to.be.deep.equal([
+      {
+        address,
+        event: 'Transfer',
+        args: {
+          from: subToEth(alice.address),
+          to: receiver,
+          value: '51',
+        },
+      },
+      {
+        address,
+        event: 'Approval',
+        args: {
+          owner: subToEth(alice.address),
+          spender: subToEth(bob.address),
+          value: '49',
+        },
+      },
+    ]);
+  });
 
-        const receiver = createEthAccount(web3);
+  itWeb3('Events emitted for transfer()', async ({ web3 }) => {
+    const collection = await createCollectionExpectSuccess({
+      mode: { type: 'Fungible', decimalPoints: 0 },
+    });
+    const alice = privateKey('//Alice');
 
-        await createFungibleItemExpectSuccess(alice, collection, { Value: 200n });
+    const receiver = createEthAccount(web3);
 
-        const address = collectionIdToAddress(collection);
-        const contract = new web3.eth.Contract(fungibleAbi as any, address);
+    await createFungibleItemExpectSuccess(alice, collection, { Value: 200n });
 
-        const events = await recordEvents(contract, async () => {
-            await transferExpectSuccess(collection, 1, alice, { ethereum: receiver }, 51, 'Fungible');
-        });
+    const address = collectionIdToAddress(collection);
+    const contract = new web3.eth.Contract(fungibleAbi as any, address);
 
-        expect(events).to.be.deep.equal([
-            {
-                address,
-                event: 'Transfer',
-                args: {
-                    from: subToEth(alice.address),
-                    to: receiver,
-                    value: '51',
-                }
-            },
-        ]);
+    const events = await recordEvents(contract, async () => {
+      await transferExpectSuccess(collection, 1, alice, { ethereum: receiver }, 51, 'Fungible');
     });
+
+    expect(events).to.be.deep.equal([
+      {
+        address,
+        event: 'Transfer',
+        args: {
+          from: subToEth(alice.address),
+          to: receiver,
+          value: '51',
+        },
+      },
+    ]);
+  });
 });
\ No newline at end of file

--- a/tests/src/eth/metadata.test.ts
+++ b/tests/src/eth/metadata.test.ts
@@ -1,53 +1,58 @@
-import { expect } from "chai";
-import privateKey from "../substrate/privateKey";
-import { createCollectionExpectSuccess } from "../util/helpers";
-import { collectionIdToAddress, createEthAccount, itWeb3, transferBalanceToEth } from "./util/helpers";
+//
+// This file is subject to the terms and conditions defined in
+// file 'LICENSE', which is part of this source code package.
+//
+
+import { expect } from 'chai';
+import privateKey from '../substrate/privateKey';
+import { createCollectionExpectSuccess } from '../util/helpers';
+import { collectionIdToAddress, createEthAccount, itWeb3, transferBalanceToEth } from './util/helpers';
 import fungibleMetadataAbi from './fungibleMetadataAbi.json';
 
 describe('Common metadata', () => {
-    itWeb3('Returns collection name', async ({ api, web3 }) => {
-        const collection = await createCollectionExpectSuccess({
-            name: 'token name',
-            mode: { type: 'NFT' }
-        });
-        const caller = createEthAccount(web3);
-        await transferBalanceToEth(api, privateKey('//Alice'), caller, 999999);
-
-        const address = collectionIdToAddress(collection);
-        const contract = new web3.eth.Contract(fungibleMetadataAbi as any, address);
-        const name = await contract.methods.name().call({ from: caller });
-
-        expect(name).to.equal('token name');
+  itWeb3('Returns collection name', async ({ api, web3 }) => {
+    const collection = await createCollectionExpectSuccess({
+      name: 'token name',
+      mode: { type: 'NFT' },
     });
+    const caller = createEthAccount(web3);
+    await transferBalanceToEth(api, privateKey('//Alice'), caller, 999999);
 
-    itWeb3('Returns symbol name', async ({ api, web3 }) => {
-        const collection = await createCollectionExpectSuccess({
-            tokenPrefix: 'TOK',
-            mode: { type: 'NFT' }
-        });
-        const caller = createEthAccount(web3);
-        await transferBalanceToEth(api, privateKey('//Alice'), caller, 999999);
+    const address = collectionIdToAddress(collection);
+    const contract = new web3.eth.Contract(fungibleMetadataAbi as any, address);
+    const name = await contract.methods.name().call({ from: caller });
 
-        const address = collectionIdToAddress(collection);
-        const contract = new web3.eth.Contract(fungibleMetadataAbi as any, address);
-        const symbol = await contract.methods.symbol().call({ from: caller });
+    expect(name).to.equal('token name');
+  });
 
-        expect(symbol).to.equal('TOK');
+  itWeb3('Returns symbol name', async ({ api, web3 }) => {
+    const collection = await createCollectionExpectSuccess({
+      tokenPrefix: 'TOK',
+      mode: { type: 'NFT' },
     });
+    const caller = createEthAccount(web3);
+    await transferBalanceToEth(api, privateKey('//Alice'), caller, 999999);
+
+    const address = collectionIdToAddress(collection);
+    const contract = new web3.eth.Contract(fungibleMetadataAbi as any, address);
+    const symbol = await contract.methods.symbol().call({ from: caller });
+
+    expect(symbol).to.equal('TOK');
+  });
 });
 
 describe('Fungible metadata', () => {
-    itWeb3('Returns fungible decimals', async ({ api, web3 }) => {
-        const collection = await createCollectionExpectSuccess({
-            mode: { type: 'Fungible', decimalPoints: 6 }
-        });
-        const caller = createEthAccount(web3);
-        await transferBalanceToEth(api, privateKey('//Alice'), caller, 999999);
+  itWeb3('Returns fungible decimals', async ({ api, web3 }) => {
+    const collection = await createCollectionExpectSuccess({
+      mode: { type: 'Fungible', decimalPoints: 6 },
+    });
+    const caller = createEthAccount(web3);
+    await transferBalanceToEth(api, privateKey('//Alice'), caller, 999999);
 
-        const address = collectionIdToAddress(collection);
-        const contract = new web3.eth.Contract(fungibleMetadataAbi as any, address);
-        const decimals = await contract.methods.decimals().call({ from: caller });
+    const address = collectionIdToAddress(collection);
+    const contract = new web3.eth.Contract(fungibleMetadataAbi as any, address);
+    const decimals = await contract.methods.decimals().call({ from: caller });
 
-        expect(+decimals).to.equal(6);
-    })
-})
\ No newline at end of file
+    expect(+decimals).to.equal(6);
+  });
+});
\ No newline at end of file

--- a/tests/src/eth/nonFungible.test.ts
+++ b/tests/src/eth/nonFungible.test.ts
@@ -1,280 +1,285 @@
-import privateKey from "../substrate/privateKey";
-import { approveExpectSuccess, createCollectionExpectSuccess, createFungibleItemExpectSuccess, createItemExpectSuccess, transferExpectSuccess, transferFromExpectSuccess } from "../util/helpers";
-import { collectionIdToAddress, createEthAccount, itWeb3, normalizeEvents, recordEvents, subToEth, transferBalanceToEth } from "./util/helpers"
+//
+// This file is subject to the terms and conditions defined in
+// file 'LICENSE', which is part of this source code package.
+//
+
+import privateKey from '../substrate/privateKey';
+import { approveExpectSuccess, createCollectionExpectSuccess, createItemExpectSuccess, transferExpectSuccess, transferFromExpectSuccess } from '../util/helpers';
+import { collectionIdToAddress, createEthAccount, itWeb3, normalizeEvents, recordEvents, subToEth, transferBalanceToEth } from './util/helpers';
 import nonFungibleAbi from './nonFungibleAbi.json';
-import { expect } from "chai";
+import { expect } from 'chai';
 
 describe('Information getting', () => {
-    itWeb3('totalSupply', async ({ web3 }) => {
-        const collection = await createCollectionExpectSuccess({
-            mode: { type: 'NFT' }
-        });
-        const alice = privateKey('//Alice');
+  itWeb3('totalSupply', async ({ web3 }) => {
+    const collection = await createCollectionExpectSuccess({
+      mode: { type: 'NFT' },
+    });
+    const alice = privateKey('//Alice');
+
+    await createItemExpectSuccess(alice, collection, 'NFT', { substrate: alice.address });
 
-        await createItemExpectSuccess(alice, collection, 'NFT', { substrate: alice.address });
+    const address = collectionIdToAddress(collection);
+    const contract = new web3.eth.Contract(nonFungibleAbi as any, address);
+    const totalSupply = await contract.methods.totalSupply().call();
 
-        const address = collectionIdToAddress(collection);
-        const contract = new web3.eth.Contract(nonFungibleAbi as any, address);
-        const totalSupply = await contract.methods.totalSupply().call();
+    // FIXME: always equals to 0, because this method is not implemented
+    expect(totalSupply).to.equal('0');
+  });
 
-        // FIXME: always equals to 0, because this method is not implemented
-        expect(totalSupply).to.equal('0');
+  itWeb3('balanceOf', async ({ web3 }) => {
+    const collection = await createCollectionExpectSuccess({
+      mode: { type: 'NFT' },
     });
+    const alice = privateKey('//Alice');
 
-    itWeb3('balanceOf', async ({ web3 }) => {
-        const collection = await createCollectionExpectSuccess({
-            mode: { type: 'NFT' }
-        });
-        const alice = privateKey('//Alice');
+    const caller = createEthAccount(web3);
+    await createItemExpectSuccess(alice, collection, 'NFT', { ethereum: caller });
+    await createItemExpectSuccess(alice, collection, 'NFT', { ethereum: caller });
+    await createItemExpectSuccess(alice, collection, 'NFT', { ethereum: caller });
 
-        const caller = createEthAccount(web3);
-        await createItemExpectSuccess(alice, collection, 'NFT', { ethereum: caller });
-        await createItemExpectSuccess(alice, collection, 'NFT', { ethereum: caller });
-        await createItemExpectSuccess(alice, collection, 'NFT', { ethereum: caller });
+    const address = collectionIdToAddress(collection);
+    const contract = new web3.eth.Contract(nonFungibleAbi as any, address);
+    const balance = await contract.methods.balanceOf(caller).call();
 
-        const address = collectionIdToAddress(collection);
-        const contract = new web3.eth.Contract(nonFungibleAbi as any, address);
-        const balance = await contract.methods.balanceOf(caller).call();
+    expect(balance).to.equal('3');
+  });
 
-        expect(balance).to.equal('3');
+  itWeb3('ownerOf', async ({ web3 }) => {
+    const collection = await createCollectionExpectSuccess({
+      mode: { type: 'NFT' },
     });
+    const alice = privateKey('//Alice');
 
-    itWeb3('ownerOf', async ({ web3 }) => {
-        const collection = await createCollectionExpectSuccess({
-            mode: { type: 'NFT' }
-        });
-        const alice = privateKey('//Alice');
+    const caller = createEthAccount(web3);
+    const tokenId = await createItemExpectSuccess(alice, collection, 'NFT', { ethereum: caller });
 
-        const caller = createEthAccount(web3);
-        const tokenId = await createItemExpectSuccess(alice, collection, 'NFT', { ethereum: caller });
+    const address = collectionIdToAddress(collection);
+    const contract = new web3.eth.Contract(nonFungibleAbi as any, address);
+    const owner = await contract.methods.ownerOf(tokenId).call();
 
-        const address = collectionIdToAddress(collection);
-        const contract = new web3.eth.Contract(nonFungibleAbi as any, address);
-        const owner = await contract.methods.ownerOf(tokenId).call();
-
-        expect(owner).to.equal(caller);
-    });
+    expect(owner).to.equal(caller);
+  });
 });
 
 describe.only('Plain calls', () => {
-    itWeb3('Can perform approve()', async ({ web3, api }) => {
-        const collection = await createCollectionExpectSuccess({
-            mode: { type: 'NFT' }
-        });
-        const alice = privateKey('//Alice');
+  itWeb3('Can perform approve()', async ({ web3, api }) => {
+    const collection = await createCollectionExpectSuccess({
+      mode: { type: 'NFT' },
+    });
+    const alice = privateKey('//Alice');
 
-        const owner = createEthAccount(web3);
-        await transferBalanceToEth(api, alice, owner, 999999999999999);
+    const owner = createEthAccount(web3);
+    await transferBalanceToEth(api, alice, owner, 999999999999999);
 
-        const tokenId = await createItemExpectSuccess(alice, collection, 'NFT', { ethereum: owner });
+    const tokenId = await createItemExpectSuccess(alice, collection, 'NFT', { ethereum: owner });
 
-        const spender = createEthAccount(web3);
+    const spender = createEthAccount(web3);
 
-        const address = collectionIdToAddress(collection);
-        const contract = new web3.eth.Contract(nonFungibleAbi as any, address);
+    const address = collectionIdToAddress(collection);
+    const contract = new web3.eth.Contract(nonFungibleAbi as any, address);
 
+    {
+      const result = await contract.methods.approve(spender, tokenId).send({ from: owner, gas: '0x1000000', gasPrice: '0x01' });
+      const events = normalizeEvents(result.events);
+
+      expect(events).to.be.deep.equal([
         {
-            const result = await contract.methods.approve(spender, tokenId).send({ from: owner, gas: '0x1000000', gasPrice: '0x01' });
-            const events = normalizeEvents(result.events);
+          address,
+          event: 'Approval',
+          args: {
+            owner,
+            approved: spender,
+            tokenId: tokenId.toString(),
+          },
+        },
+      ]);
+    }
+  });
 
-            expect(events).to.be.deep.equal([
-                {
-                    address,
-                    event: 'Approval',
-                    args: {
-                        owner,
-                        approved: spender,
-                        tokenId: tokenId.toString(),
-                    }
-                }
-            ]);
-        }
+  itWeb3('Can perform transferFrom()', async ({ web3, api }) => {
+    const collection = await createCollectionExpectSuccess({
+      mode: { type: 'NFT' },
     });
-
-    itWeb3('Can perform transferFrom()', async ({ web3, api }) => {
-        const collection = await createCollectionExpectSuccess({
-            mode: { type: 'NFT' }
-        });
-        const alice = privateKey('//Alice');
+    const alice = privateKey('//Alice');
 
-        const owner = createEthAccount(web3);
-        await transferBalanceToEth(api, alice, owner, 999999999999999);
+    const owner = createEthAccount(web3);
+    await transferBalanceToEth(api, alice, owner, 999999999999999);
 
-        const tokenId = await createItemExpectSuccess(alice, collection, 'NFT', { ethereum: owner });
+    const tokenId = await createItemExpectSuccess(alice, collection, 'NFT', { ethereum: owner });
 
-        const spender = createEthAccount(web3);
-        await transferBalanceToEth(api, alice, spender, 999999999999999);
+    const spender = createEthAccount(web3);
+    await transferBalanceToEth(api, alice, spender, 999999999999999);
 
-        const receiver = createEthAccount(web3);
+    const receiver = createEthAccount(web3);
 
-        const address = collectionIdToAddress(collection);
-        const contract = new web3.eth.Contract(nonFungibleAbi as any, address);
+    const address = collectionIdToAddress(collection);
+    const contract = new web3.eth.Contract(nonFungibleAbi as any, address);
 
-        await contract.methods.approve(spender, tokenId).send({ from: owner, gas: '0x1000000', gasPrice: '0x01' });
+    await contract.methods.approve(spender, tokenId).send({ from: owner, gas: '0x1000000', gasPrice: '0x01' });
 
+    {
+      const result = await contract.methods.transferFrom(owner, receiver, tokenId).send({ from: spender, gas: '0x1000000', gasPrice: '0x01' });
+      const events = normalizeEvents(result.events);
+      expect(events).to.be.deep.equal([
         {
-            const result = await contract.methods.transferFrom(owner, receiver, tokenId).send({ from: spender, gas: '0x1000000', gasPrice: '0x01' });
-            const events = normalizeEvents(result.events);
-            expect(events).to.be.deep.equal([
-                {
-                    address,
-                    event: 'Transfer',
-                    args: {
-                        from: owner,
-                        to: receiver,
-                        tokenId: tokenId.toString(),
-                    },
-                },
-            ]);
-        }
+          address,
+          event: 'Transfer',
+          args: {
+            from: owner,
+            to: receiver,
+            tokenId: tokenId.toString(),
+          },
+        },
+      ]);
+    }
 
-        {
-            const balance = await contract.methods.balanceOf(receiver).call();
-            expect(+balance).to.equal(1);
-        }
+    {
+      const balance = await contract.methods.balanceOf(receiver).call();
+      expect(+balance).to.equal(1);
+    }
 
-        {
-            const balance = await contract.methods.balanceOf(owner).call();
-            expect(+balance).to.equal(0);
-        }
-    });
+    {
+      const balance = await contract.methods.balanceOf(owner).call();
+      expect(+balance).to.equal(0);
+    }
+  });
 
-    itWeb3('Can perform transfer()', async ({ web3, api }) => {
-        const collection = await createCollectionExpectSuccess({
-            mode: { type: 'NFT' }
-        });
-        const alice = privateKey('//Alice');
+  itWeb3('Can perform transfer()', async ({ web3, api }) => {
+    const collection = await createCollectionExpectSuccess({
+      mode: { type: 'NFT' },
+    });
+    const alice = privateKey('//Alice');
 
-        const owner = createEthAccount(web3);
-        await transferBalanceToEth(api, alice, owner, 999999999999999);
+    const owner = createEthAccount(web3);
+    await transferBalanceToEth(api, alice, owner, 999999999999999);
 
-        const tokenId = await createItemExpectSuccess(alice, collection, 'NFT', { ethereum: owner });
+    const tokenId = await createItemExpectSuccess(alice, collection, 'NFT', { ethereum: owner });
 
-        const receiver = createEthAccount(web3);
-        await transferBalanceToEth(api, alice, receiver, 999999999999999);
+    const receiver = createEthAccount(web3);
+    await transferBalanceToEth(api, alice, receiver, 999999999999999);
 
-        const address = collectionIdToAddress(collection);
-        const contract = new web3.eth.Contract(nonFungibleAbi as any, address);
+    const address = collectionIdToAddress(collection);
+    const contract = new web3.eth.Contract(nonFungibleAbi as any, address);
 
+    {
+      const result = await contract.methods.transfer(receiver, tokenId).send({ from: owner, gas: '0x1000000', gasPrice: '0x01' });
+      console.log(result);
+      const events = normalizeEvents(result.events);
+      expect(events).to.be.deep.equal([
         {
-            const result = await contract.methods.transfer(receiver, tokenId).send({ from: owner, gas: '0x1000000', gasPrice: '0x01' });
-            console.log(result);
-            const events = normalizeEvents(result.events);
-            expect(events).to.be.deep.equal([
-                {
-                    address,
-                    event: 'Transfer',
-                    args: {
-                        from: owner,
-                        to: receiver,
-                        tokenId: tokenId.toString(),
-                    }
-                },
-            ])
-        }
+          address,
+          event: 'Transfer',
+          args: {
+            from: owner,
+            to: receiver,
+            tokenId: tokenId.toString(),
+          },
+        },
+      ]);
+    }
 
-        {
-            const balance = await contract.methods.balanceOf(owner).call();
-            expect(+balance).to.equal(0);
-        }
+    {
+      const balance = await contract.methods.balanceOf(owner).call();
+      expect(+balance).to.equal(0);
+    }
 
-        {
-            const balance = await contract.methods.balanceOf(receiver).call();
-            expect(+balance).to.equal(1);
-        }
-    });
+    {
+      const balance = await contract.methods.balanceOf(receiver).call();
+      expect(+balance).to.equal(1);
+    }
+  });
 });
 
 describe('Substrate calls', () => {
-    itWeb3('Events emitted for approve()', async ({ web3 }) => {
-        const collection = await createCollectionExpectSuccess({
-            mode: { type: 'NFT' }
-        });
-        const alice = privateKey('//Alice');
-
-        const receiver = createEthAccount(web3);
+  itWeb3('Events emitted for approve()', async ({ web3 }) => {
+    const collection = await createCollectionExpectSuccess({
+      mode: { type: 'NFT' },
+    });
+    const alice = privateKey('//Alice');
 
-        const tokenId = await createItemExpectSuccess(alice, collection, 'NFT');
+    const receiver = createEthAccount(web3);
 
-        const address = collectionIdToAddress(collection);
-        const contract = new web3.eth.Contract(nonFungibleAbi as any, address);
+    const tokenId = await createItemExpectSuccess(alice, collection, 'NFT');
 
-        const events = await recordEvents(contract, async () => {
-            await approveExpectSuccess(collection, tokenId, alice, { ethereum: receiver }, 1);
-        });
+    const address = collectionIdToAddress(collection);
+    const contract = new web3.eth.Contract(nonFungibleAbi as any, address);
 
-        expect(events).to.be.deep.equal([
-            {
-                address,
-                event: 'Approval',
-                args: {
-                    owner: subToEth(alice.address),
-                    approved: receiver,
-                    tokenId: tokenId.toString(),
-                }
-            }
-        ]);
+    const events = await recordEvents(contract, async () => {
+      await approveExpectSuccess(collection, tokenId, alice, { ethereum: receiver }, 1);
     });
 
-    itWeb3('Events emitted for transferFrom()', async ({ web3 }) => {
-        const collection = await createCollectionExpectSuccess({
-            mode: { type: 'NFT' }
-        });
-        const alice = privateKey('//Alice');
-        const bob = privateKey('//Bob');
+    expect(events).to.be.deep.equal([
+      {
+        address,
+        event: 'Approval',
+        args: {
+          owner: subToEth(alice.address),
+          approved: receiver,
+          tokenId: tokenId.toString(),
+        },
+      },
+    ]);
+  });
 
-        const receiver = createEthAccount(web3);
+  itWeb3('Events emitted for transferFrom()', async ({ web3 }) => {
+    const collection = await createCollectionExpectSuccess({
+      mode: { type: 'NFT' },
+    });
+    const alice = privateKey('//Alice');
+    const bob = privateKey('//Bob');
 
-        const tokenId = await createItemExpectSuccess(alice, collection, 'NFT');
-        await approveExpectSuccess(collection, tokenId, alice, bob, 1);
+    const receiver = createEthAccount(web3);
 
-        const address = collectionIdToAddress(collection);
-        const contract = new web3.eth.Contract(nonFungibleAbi as any, address);
+    const tokenId = await createItemExpectSuccess(alice, collection, 'NFT');
+    await approveExpectSuccess(collection, tokenId, alice, bob, 1);
 
-        const events = await recordEvents(contract, async () => {
-            await transferFromExpectSuccess(collection, tokenId, bob, alice, { ethereum: receiver }, 1, 'NFT');
-        });
+    const address = collectionIdToAddress(collection);
+    const contract = new web3.eth.Contract(nonFungibleAbi as any, address);
 
-        expect(events).to.be.deep.equal([
-            {
-                address,
-                event: 'Transfer',
-                args: {
-                    from: subToEth(alice.address),
-                    to: receiver,
-                    tokenId: tokenId.toString(),
-                }
-            },
-        ]);
+    const events = await recordEvents(contract, async () => {
+      await transferFromExpectSuccess(collection, tokenId, bob, alice, { ethereum: receiver }, 1, 'NFT');
     });
 
-    itWeb3('Events emitted for transfer()', async ({ web3 }) => {
-        const collection = await createCollectionExpectSuccess({
-            mode: { type: 'NFT' }
-        });
-        const alice = privateKey('//Alice');
+    expect(events).to.be.deep.equal([
+      {
+        address,
+        event: 'Transfer',
+        args: {
+          from: subToEth(alice.address),
+          to: receiver,
+          tokenId: tokenId.toString(),
+        },
+      },
+    ]);
+  });
 
-        const receiver = createEthAccount(web3);
+  itWeb3('Events emitted for transfer()', async ({ web3 }) => {
+    const collection = await createCollectionExpectSuccess({
+      mode: { type: 'NFT' },
+    });
+    const alice = privateKey('//Alice');
 
-        const tokenId = await createItemExpectSuccess(alice, collection, 'NFT');
+    const receiver = createEthAccount(web3);
 
-        const address = collectionIdToAddress(collection);
-        const contract = new web3.eth.Contract(nonFungibleAbi as any, address);
+    const tokenId = await createItemExpectSuccess(alice, collection, 'NFT');
 
-        const events = await recordEvents(contract, async () => {
-            await transferExpectSuccess(collection, tokenId, alice, { ethereum: receiver }, 1, 'NFT');
-        });
+    const address = collectionIdToAddress(collection);
+    const contract = new web3.eth.Contract(nonFungibleAbi as any, address);
 
-        expect(events).to.be.deep.equal([
-            {
-                address,
-                event: 'Transfer',
-                args: {
-                    from: subToEth(alice.address),
-                    to: receiver,
-                    tokenId: tokenId.toString(),
-                }
-            },
-        ]);
+    const events = await recordEvents(contract, async () => {
+      await transferExpectSuccess(collection, tokenId, alice, { ethereum: receiver }, 1, 'NFT');
     });
+
+    expect(events).to.be.deep.equal([
+      {
+        address,
+        event: 'Transfer',
+        args: {
+          from: subToEth(alice.address),
+          to: receiver,
+          tokenId: tokenId.toString(),
+        },
+      },
+    ]);
+  });
 });
\ No newline at end of file

--- a/tests/src/eth/util/helpers.ts
+++ b/tests/src/eth/util/helpers.ts
@@ -1,70 +1,75 @@
-import { ApiPromise } from "@polkadot/api";
-import { addressToEvm, evmToAddress } from "@polkadot/util-crypto";
-import Web3 from "web3";
-import usingApi, { submitTransactionAsync } from "../../substrate/substrate-api";
+//
+// This file is subject to the terms and conditions defined in
+// file 'LICENSE', which is part of this source code package.
+//
+
+import { ApiPromise } from '@polkadot/api';
+import { addressToEvm, evmToAddress } from '@polkadot/util-crypto';
+import Web3 from 'web3';
+import usingApi, { submitTransactionAsync } from '../../substrate/substrate-api';
 import { IKeyringPair } from '@polkadot/types/types';
-import { expect } from "chai";
-import { getGenericResult } from "../../util/helpers";
+import { expect } from 'chai';
+import { getGenericResult } from '../../util/helpers';
 
 let web3Connected = false;
 export async function usingWeb3<T>(cb: (web3: Web3) => Promise<T> | T): Promise<T> {
-    if (web3Connected) throw new Error('do not nest usingWeb3 calls');
-    web3Connected = true;
+  if (web3Connected) throw new Error('do not nest usingWeb3 calls');
+  web3Connected = true;
 
-    const provider = new Web3.providers.WebsocketProvider("http://localhost:9944");
-    const web3 = new Web3(provider);
+  const provider = new Web3.providers.WebsocketProvider('http://localhost:9944');
+  const web3 = new Web3(provider);
 
-    try {
-        return await cb(web3);
-    } finally {
-        // provider.disconnect(3000, 'normal disconnect');
-        provider.connection.close();
-        web3Connected = false;
-    }
+  try {
+    return await cb(web3);
+  } finally {
+    // provider.disconnect(3000, 'normal disconnect');
+    provider.connection.close();
+    web3Connected = false;
+  }
 }
 
 export function collectionIdToAddress(address: number): string {
-    if (address >= 0xffffffff || address < 0) throw new Error('id overflow');
-    const buf = Buffer.from([0x17, 0xc4, 0xe6, 0x45, 0x3c, 0xc4, 0x9a, 0xaa, 0xae, 0xac, 0xa8, 0x94, 0xe6, 0xd9, 0x68, 0x3e,
-        address >> 24,
-        (address >> 16) & 0xff,
-        (address >> 8) & 0xff,
-        address & 0xff,
-    ]);
-    return Web3.utils.toChecksumAddress('0x' + buf.toString('hex'));
+  if (address >= 0xffffffff || address < 0) throw new Error('id overflow');
+  const buf = Buffer.from([0x17, 0xc4, 0xe6, 0x45, 0x3c, 0xc4, 0x9a, 0xaa, 0xae, 0xac, 0xa8, 0x94, 0xe6, 0xd9, 0x68, 0x3e,
+    address >> 24,
+    (address >> 16) & 0xff,
+    (address >> 8) & 0xff,
+    address & 0xff,
+  ]);
+  return Web3.utils.toChecksumAddress('0x' + buf.toString('hex'));
 }
 
 export function createEthAccount(web3: Web3) {
-    const account = web3.eth.accounts.create();
-    web3.eth.accounts.wallet.add(account.privateKey);
-    return account.address;
+  const account = web3.eth.accounts.create();
+  web3.eth.accounts.wallet.add(account.privateKey);
+  return account.address;
 }
 
 export async function transferBalanceToEth(api: ApiPromise, source: IKeyringPair, target: string, amount: number) {
-    const tx = api.tx.balances.transfer(evmToAddress(target), amount);
-    const events = await submitTransactionAsync(source, tx);
-    const result = getGenericResult(events);
-    expect(result.success).to.be.true;
+  const tx = api.tx.balances.transfer(evmToAddress(target), amount);
+  const events = await submitTransactionAsync(source, tx);
+  const result = getGenericResult(events);
+  expect(result.success).to.be.true;
 }
 
 export async function itWeb3(name: string, cb: (apis: { web3: Web3, api: ApiPromise }) => any, opts: { only?: boolean, skip?: boolean } = {}) {
-    let i: any = it;
-    if (opts.only) i = i.only;
-    else if (opts.skip) i = i.skip;
-    i(name, async () => {
-        await usingApi(async api => {
-            await usingWeb3(async web3 => {
-                await cb({ api, web3 });
-            });
-        });
+  let i: any = it;
+  if (opts.only) i = i.only;
+  else if (opts.skip) i = i.skip;
+  i(name, async () => {
+    await usingApi(async api => {
+      await usingWeb3(async web3 => {
+        await cb({ api, web3 });
+      });
     });
+  });
 }
 itWeb3.only = (name: string, cb: (apis: { web3: Web3, api: ApiPromise }) => any) => itWeb3(name, cb, { only: true });
 itWeb3.skip = (name: string, cb: (apis: { web3: Web3, api: ApiPromise }) => any) => itWeb3(name, cb, { skip: true });
 
 export async function generateSubstrateEthPair(web3: Web3) {
-    let account = web3.eth.accounts.create();
-    const evm = evmToAddress(account.address);
+  const account = web3.eth.accounts.create();
+  evmToAddress(account.address);
 }
 
 type NormalizedEvent = {
@@ -74,43 +79,43 @@
 };
 
 export function normalizeEvents(events: any): NormalizedEvent[] {
-    const output = [];
-    for (let key of Object.keys(events)) {
-        if (key.match(/^[0-9]+$/)) {
-            output.push(events[key]);
-        } else if (Array.isArray(events[key])) {
-            output.push(...events[key]);
-        } else {
-            output.push(events[key]);
-        }
+  const output = [];
+  for (const key of Object.keys(events)) {
+    if (key.match(/^[0-9]+$/)) {
+      output.push(events[key]);
+    } else if (Array.isArray(events[key])) {
+      output.push(...events[key]);
+    } else {
+      output.push(events[key]);
     }
-    output.sort((a, b) => a.logIndex - b.logIndex);
-    return output.map(({ address, event, returnValues }) => {
-        const args: { [key: string]: string } = {};
-        for (let key of Object.keys(returnValues)) {
-            if (!key.match(/^[0-9]+$/)) {
-                args[key] = returnValues[key];
-            }
-        }
-        return {
-            address,
-            event,
-            args,
-        };
-    });
+  }
+  output.sort((a, b) => a.logIndex - b.logIndex);
+  return output.map(({ address, event, returnValues }) => {
+    const args: { [key: string]: string } = {};
+    for (const key of Object.keys(returnValues)) {
+      if (!key.match(/^[0-9]+$/)) {
+        args[key] = returnValues[key];
+      }
+    }
+    return {
+      address,
+      event,
+      args,
+    };
+  });
 }
 
 export async function recordEvents(contract: any, action: () => Promise<void>): Promise<NormalizedEvent[]> {
-    const out: any = [];
-    contract.events.allEvents((_: any, event: any) => {
-        out.push(event);
-    });
-    await action();
-    return normalizeEvents(out);
+  const out: any = [];
+  contract.events.allEvents((_: any, event: any) => {
+    out.push(event);
+  });
+  await action();
+  return normalizeEvents(out);
 }
 
 export function subToEth(eth: string): string {
-    const bytes = addressToEvm(eth);
-    const string = '0x' + Buffer.from(bytes).toString('hex');
-    return Web3.utils.toChecksumAddress(string);
+  const bytes = addressToEvm(eth);
+  const string = '0x' + Buffer.from(bytes).toString('hex');
+  return Web3.utils.toChecksumAddress(string);
 }
\ No newline at end of file

--- a/tests/src/inflation.test.ts
+++ b/tests/src/inflation.test.ts
@@ -5,25 +5,13 @@
 
 import chai from 'chai';
 import chaiAsPromised from 'chai-as-promised';
-import { default as usingApi } from "./substrate/substrate-api";
-import privateKey from "./substrate/privateKey";
+import { default as usingApi } from './substrate/substrate-api';
 import { BigNumber } from 'bignumber.js';
-import { IKeyringPair } from '@polkadot/types/types';
 
 chai.use(chaiAsPromised);
 const expect = chai.expect;
-
-let alice: IKeyringPair;
-let bob: IKeyringPair;
 
 describe('integration test: Inflation', () => {
-  before(async () => {
-    await usingApi(async (api) => {
-      alice = privateKey('//Alice');
-      bob = privateKey('//Bob');
-    });
-  });
-
   it('First year inflation is 10%', async () => {
     await usingApi(async (api) => {
 

--- a/tests/src/overflow.test.ts
+++ b/tests/src/overflow.test.ts
@@ -3,65 +3,65 @@
 // file 'LICENSE', which is part of this source code package.
 //
 
-import { IKeyringPair } from "@polkadot/types/types";
+import { IKeyringPair } from '@polkadot/types/types';
 import chai from 'chai';
-import chaiAsPromised from "chai-as-promised";
-import privateKey from "./substrate/privateKey";
-import usingApi from "./substrate/substrate-api";
-import { approveExpectFail, approveExpectSuccess, createCollectionExpectSuccess, createFungibleItemExpectSuccess, getAllowance, getFungibleBalance, transferExpectFail, transferExpectSuccess, transferFromExpectFail, transferFromExpectSuccess, U128_MAX } from "./util/helpers";
+import chaiAsPromised from 'chai-as-promised';
+import privateKey from './substrate/privateKey';
+import usingApi from './substrate/substrate-api';
+import { approveExpectFail, approveExpectSuccess, createCollectionExpectSuccess, createFungibleItemExpectSuccess, getAllowance, getFungibleBalance, transferExpectFail, transferExpectSuccess, transferFromExpectFail, transferFromExpectSuccess, U128_MAX } from './util/helpers';
 
 chai.use(chaiAsPromised);
 const expect = chai.expect;
 
 describe('Integration Test fungible overflows', () => {
-    let alice: IKeyringPair;
-    let bob: IKeyringPair;
-    let charlie: IKeyringPair;
+  let alice: IKeyringPair;
+  let bob: IKeyringPair;
+  let charlie: IKeyringPair;
 
-    before(async () => {
-        await usingApi(async () => {
-            alice = privateKey('//Alice');
-            bob = privateKey('//Bob');
-            charlie = privateKey('//Charlie');
-        });
+  before(async () => {
+    await usingApi(async () => {
+      alice = privateKey('//Alice');
+      bob = privateKey('//Bob');
+      charlie = privateKey('//Charlie');
     });
+  });
 
-    it('fails when overflows on transfer', async () => {
-        const fungibleCollectionId = await createCollectionExpectSuccess({ mode: { type: 'Fungible', decimalPoints: 0 } });
+  it('fails when overflows on transfer', async () => {
+    const fungibleCollectionId = await createCollectionExpectSuccess({ mode: { type: 'Fungible', decimalPoints: 0 } });
 
-        await createFungibleItemExpectSuccess(alice, fungibleCollectionId, { Value: U128_MAX });
-        await transferExpectSuccess(fungibleCollectionId, 0, alice, bob, U128_MAX, 'Fungible');
+    await createFungibleItemExpectSuccess(alice, fungibleCollectionId, { Value: U128_MAX });
+    await transferExpectSuccess(fungibleCollectionId, 0, alice, bob, U128_MAX, 'Fungible');
 
-        await createFungibleItemExpectSuccess(alice, fungibleCollectionId, { Value: 1n });
-        await transferExpectFail(fungibleCollectionId, 0, alice, bob, 1, 'Fungible');
+    await createFungibleItemExpectSuccess(alice, fungibleCollectionId, { Value: 1n });
+    await transferExpectFail(fungibleCollectionId, 0, alice, bob, 1, 'Fungible');
 
-        expect(await getFungibleBalance(fungibleCollectionId, alice.address)).to.equal(1n);
-        expect(await getFungibleBalance(fungibleCollectionId, bob.address)).to.equal(U128_MAX);
-    });
+    expect(await getFungibleBalance(fungibleCollectionId, alice.address)).to.equal(1n);
+    expect(await getFungibleBalance(fungibleCollectionId, bob.address)).to.equal(U128_MAX);
+  });
 
-    it('fails on allowance overflow', async () => {
-        const fungibleCollectionId = await createCollectionExpectSuccess({ mode: { type: 'Fungible', decimalPoints: 0 } });
+  it('fails on allowance overflow', async () => {
+    const fungibleCollectionId = await createCollectionExpectSuccess({ mode: { type: 'Fungible', decimalPoints: 0 } });
 
-        await createFungibleItemExpectSuccess(alice, fungibleCollectionId, { Value: U128_MAX });
-        await approveExpectSuccess(fungibleCollectionId, 0, alice, bob, U128_MAX);
-        await approveExpectFail(fungibleCollectionId, 0, alice, bob, U128_MAX);
-    });
+    await createFungibleItemExpectSuccess(alice, fungibleCollectionId, { Value: U128_MAX });
+    await approveExpectSuccess(fungibleCollectionId, 0, alice, bob, U128_MAX);
+    await approveExpectFail(fungibleCollectionId, 0, alice, bob, U128_MAX);
+  });
 
-    it('fails when overflows on transferFrom', async () => {
-        const fungibleCollectionId = await createCollectionExpectSuccess({ mode: { type: 'Fungible', decimalPoints: 0 } });
+  it('fails when overflows on transferFrom', async () => {
+    const fungibleCollectionId = await createCollectionExpectSuccess({ mode: { type: 'Fungible', decimalPoints: 0 } });
 
-        await createFungibleItemExpectSuccess(alice, fungibleCollectionId, { Value: U128_MAX });
-        await approveExpectSuccess(fungibleCollectionId, 0, alice, bob, U128_MAX);
-        await transferFromExpectSuccess(fungibleCollectionId, 0, bob, alice, charlie, U128_MAX, 'Fungible');
+    await createFungibleItemExpectSuccess(alice, fungibleCollectionId, { Value: U128_MAX });
+    await approveExpectSuccess(fungibleCollectionId, 0, alice, bob, U128_MAX);
+    await transferFromExpectSuccess(fungibleCollectionId, 0, bob, alice, charlie, U128_MAX, 'Fungible');
 
-        expect(await getFungibleBalance(fungibleCollectionId, charlie.address)).to.equal(U128_MAX);
-        expect((await getAllowance(fungibleCollectionId, 0, alice.address, bob.address)).toString()).to.equal('0');
+    expect(await getFungibleBalance(fungibleCollectionId, charlie.address)).to.equal(U128_MAX);
+    expect((await getAllowance(fungibleCollectionId, 0, alice.address, bob.address)).toString()).to.equal('0');
 
-        await createFungibleItemExpectSuccess(alice, fungibleCollectionId, { Value: U128_MAX });
-        await approveExpectSuccess(fungibleCollectionId, 0, alice, bob, 1n);
-        await transferFromExpectFail(fungibleCollectionId, 0, bob, alice, charlie, 1);
+    await createFungibleItemExpectSuccess(alice, fungibleCollectionId, { Value: U128_MAX });
+    await approveExpectSuccess(fungibleCollectionId, 0, alice, bob, 1n);
+    await transferFromExpectFail(fungibleCollectionId, 0, bob, alice, charlie, 1);
 
-        expect(await getFungibleBalance(fungibleCollectionId, charlie.address)).to.equal(U128_MAX);
-        expect((await getAllowance(fungibleCollectionId, 0, alice.address, bob.address)).toString()).to.equal('1');
-    });
+    expect(await getFungibleBalance(fungibleCollectionId, charlie.address)).to.equal(U128_MAX);
+    expect((await getAllowance(fungibleCollectionId, 0, alice.address, bob.address)).toString()).to.equal('1');
+  });
 });

--- a/tests/src/pallet-presence.test.ts
+++ b/tests/src/pallet-presence.test.ts
@@ -3,9 +3,9 @@
 // file 'LICENSE', which is part of this source code package.
 //
 
-import { ApiPromise } from "@polkadot/api";
-import { expect } from "chai";
-import usingApi from "./substrate/substrate-api";
+import { ApiPromise } from '@polkadot/api';
+import { expect } from 'chai';
+import usingApi from './substrate/substrate-api';
 
 function getModuleNames(api: ApiPromise): string[] {
   return api.runtimeMetadata.asLatest.modules.map(m => m.name.toString().toLowerCase());
@@ -14,12 +14,12 @@
 // Pallets that must always be present
 const requiredPallets = [
   'nft', 'inflation', 'balances', 'contracts', 'randomnesscollectiveflip', 'system', 'timestamp', 'transactionpayment', 'treasury', 'vesting', 'evm', 'ethereum',
-  'scheduler', 'nftpayment', 'charging'
+  'scheduler', 'nftpayment', 'charging',
 ];
 
 // Pallets that depend on consensus and governance configuration
 const consensusPallets = [
-  'sudo', 'aura'
+  'sudo', 'aura',
 ];
 
 describe('Pallet presence', () => {

--- a/tests/src/removeCollectionSponsor.test.ts
+++ b/tests/src/removeCollectionSponsor.test.ts
@@ -5,27 +5,21 @@
 
 import chai from 'chai';
 import chaiAsPromised from 'chai-as-promised';
-import { default as usingApi, submitTransactionAsync, submitTransactionExpectFailAsync } from "./substrate/substrate-api";
+import { default as usingApi, submitTransactionExpectFailAsync } from './substrate/substrate-api';
 import { 
   createCollectionExpectSuccess, 
   setCollectionSponsorExpectSuccess, 
   destroyCollectionExpectSuccess, 
-  setCollectionSponsorExpectFailure,
   confirmSponsorshipExpectSuccess,
   confirmSponsorshipExpectFailure,
   createItemExpectSuccess,
   findUnusedAddress,
-  getGenericResult,
-  enableWhiteListExpectSuccess,
-  enablePublicMintingExpectSuccess,
-  addToWhiteListExpectSuccess,
   removeCollectionSponsorExpectSuccess,
   removeCollectionSponsorExpectFailure,
   normalizeAccountId,
-} from "./util/helpers";
-import { Keyring } from "@polkadot/api";
-import { IKeyringPair } from "@polkadot/types/types";
-import type { AccountId } from '@polkadot/types/interfaces';
+} from './util/helpers';
+import { Keyring } from '@polkadot/api';
+import { IKeyringPair } from '@polkadot/types/types';
 import { BigNumber } from 'bignumber.js';
 
 chai.use(chaiAsPromised);
@@ -33,16 +27,14 @@
 
 let alice: IKeyringPair;
 let bob: IKeyringPair;
-let charlie: IKeyringPair;
 
 describe('integration test: ext. removeCollectionSponsor():', () => {
 
   before(async () => {
-    await usingApi(async (api) => {
+    await usingApi(async () => {
       const keyring = new Keyring({ type: 'sr25519' });
-      alice = keyring.addFromUri(`//Alice`);
-      bob = keyring.addFromUri(`//Bob`);
-      charlie = keyring.addFromUri(`//Charlie`);
+      alice = keyring.addFromUri('//Alice');
+      bob = keyring.addFromUri('//Bob');
     });
   });
 
@@ -65,7 +57,7 @@
       const badTransaction = async function () { 
         await submitTransactionExpectFailAsync(zeroBalance, zeroToAlice);
       };
-      await expect(badTransaction()).to.be.rejectedWith("Inability to pay some fees");
+      await expect(badTransaction()).to.be.rejectedWith('Inability to pay some fees');
       const BsponsorBalance = new BigNumber((await api.query.system.account(bob.address)).data.free.toString());
 
       expect(BsponsorBalance.isEqualTo(AsponsorBalance)).to.be.true;
@@ -95,19 +87,18 @@
 
 describe('(!negative test!) integration test: ext. removeCollectionSponsor():', () => {
   before(async () => {
-    await usingApi(async (api) => {
+    await usingApi(async () => {
       const keyring = new Keyring({ type: 'sr25519' });
-      alice = keyring.addFromUri(`//Alice`);
-      bob = keyring.addFromUri(`//Bob`);
-      charlie = keyring.addFromUri(`//Charlie`);
+      alice = keyring.addFromUri('//Alice');
+      bob = keyring.addFromUri('//Bob');
     });
   });
 
   it('(!negative test!) Remove sponsor for a collection that never existed', async () => {
     // Find the collection that never existed
-    const collectionId = 0;
+    let collectionId = 0;
     await usingApi(async (api) => {
-      const collectionId = parseInt((await api.query.nft.createdCollectionCount()).toString()) + 1;
+      collectionId = parseInt((await api.query.nft.createdCollectionCount()).toString()) + 1;
     });
 
     await removeCollectionSponsorExpectFailure(collectionId);

--- a/tests/src/removeFromContractWhiteList.test.ts
+++ b/tests/src/removeFromContractWhiteList.test.ts
@@ -3,79 +3,79 @@
 // file 'LICENSE', which is part of this source code package.
 //
 
-import privateKey from "./substrate/privateKey";
-import usingApi from "./substrate/substrate-api";
-import { deployFlipper, toggleFlipValueExpectFailure, toggleFlipValueExpectSuccess } from "./util/contracthelpers";
-import { addToContractWhiteListExpectSuccess, isWhitelistedInContract, removeFromContractWhiteListExpectFailure, removeFromContractWhiteListExpectSuccess, toggleContractWhitelistExpectSuccess } from "./util/helpers";
+import privateKey from './substrate/privateKey';
+import usingApi from './substrate/substrate-api';
+import { deployFlipper, toggleFlipValueExpectFailure, toggleFlipValueExpectSuccess } from './util/contracthelpers';
+import { addToContractWhiteListExpectSuccess, isWhitelistedInContract, removeFromContractWhiteListExpectFailure, removeFromContractWhiteListExpectSuccess, toggleContractWhitelistExpectSuccess } from './util/helpers';
 import { IKeyringPair } from '@polkadot/types/types';
-import { expect } from "chai";
+import { expect } from 'chai';
 
 describe('Integration Test removeFromContractWhiteList', () => {
-    let bob: IKeyringPair;
+  let bob: IKeyringPair;
 
-    before(async () => {
-        await usingApi(async () => {
-            bob = privateKey('//Bob');
-        });
+  before(async () => {
+    await usingApi(async () => {
+      bob = privateKey('//Bob');
     });
+  });
 
-    it('user is no longer whitelisted after removal', async () => {
-        await usingApi(async (api) => {
-            const [flipper, deployer] = await deployFlipper(api);
+  it('user is no longer whitelisted after removal', async () => {
+    await usingApi(async (api) => {
+      const [flipper, deployer] = await deployFlipper(api);
 
-            await addToContractWhiteListExpectSuccess(deployer, flipper.address.toString(), bob.address);
-            await removeFromContractWhiteListExpectSuccess(deployer, flipper.address.toString(), bob.address);
+      await addToContractWhiteListExpectSuccess(deployer, flipper.address.toString(), bob.address);
+      await removeFromContractWhiteListExpectSuccess(deployer, flipper.address.toString(), bob.address);
 
-            expect(await isWhitelistedInContract(flipper.address, bob.address)).to.be.false;
-        });
+      expect(await isWhitelistedInContract(flipper.address, bob.address)).to.be.false;
     });
+  });
 
-    it('user can\'t execute contract after removal', async () => {
-        await usingApi(async (api) => {
-            const [flipper, deployer] = await deployFlipper(api);
-            await toggleContractWhitelistExpectSuccess(deployer, flipper.address.toString(), true);
+  it('user can\'t execute contract after removal', async () => {
+    await usingApi(async (api) => {
+      const [flipper, deployer] = await deployFlipper(api);
+      await toggleContractWhitelistExpectSuccess(deployer, flipper.address.toString(), true);
 
-            await addToContractWhiteListExpectSuccess(deployer, flipper.address.toString(), bob.address);
-            await toggleFlipValueExpectSuccess(bob, flipper);
+      await addToContractWhiteListExpectSuccess(deployer, flipper.address.toString(), bob.address);
+      await toggleFlipValueExpectSuccess(bob, flipper);
 
-            await removeFromContractWhiteListExpectSuccess(deployer, flipper.address.toString(), bob.address);
-            await toggleFlipValueExpectFailure(bob, flipper);
-        });
+      await removeFromContractWhiteListExpectSuccess(deployer, flipper.address.toString(), bob.address);
+      await toggleFlipValueExpectFailure(bob, flipper);
     });
+  });
 
-    it('can be called twice', async () => {
-        await usingApi(async (api) => {
-            const [flipper, deployer] = await deployFlipper(api);
+  it('can be called twice', async () => {
+    await usingApi(async (api) => {
+      const [flipper, deployer] = await deployFlipper(api);
 
-            await addToContractWhiteListExpectSuccess(deployer, flipper.address.toString(), bob.address);
-            await removeFromContractWhiteListExpectSuccess(deployer, flipper.address.toString(), bob.address);
-            await removeFromContractWhiteListExpectSuccess(deployer, flipper.address.toString(), bob.address);
-        });
+      await addToContractWhiteListExpectSuccess(deployer, flipper.address.toString(), bob.address);
+      await removeFromContractWhiteListExpectSuccess(deployer, flipper.address.toString(), bob.address);
+      await removeFromContractWhiteListExpectSuccess(deployer, flipper.address.toString(), bob.address);
     });
+  });
 });
 
 describe('Negative Integration Test removeFromContractWhiteList', () => {
-    let alice: IKeyringPair;
-    let bob: IKeyringPair;
+  let alice: IKeyringPair;
+  let bob: IKeyringPair;
 
-    before(async () => {
-        await usingApi(async () => {
-            alice = privateKey('//Alice');
-            bob = privateKey('//Bob');
-        });
+  before(async () => {
+    await usingApi(async () => {
+      alice = privateKey('//Alice');
+      bob = privateKey('//Bob');
     });
+  });
 
-    it('fails when called with non-contract address', async () => {
-        await usingApi(async () => {
-            await removeFromContractWhiteListExpectFailure(alice, alice.address, bob.address);
-        });
+  it('fails when called with non-contract address', async () => {
+    await usingApi(async () => {
+      await removeFromContractWhiteListExpectFailure(alice, alice.address, bob.address);
     });
+  });
 
-    it('fails when executed by non owner', async () => {
-        await usingApi(async (api) => {
-            const [flipper, _] = await deployFlipper(api);
+  it('fails when executed by non owner', async () => {
+    await usingApi(async (api) => {
+      const [flipper] = await deployFlipper(api);
 
-            await removeFromContractWhiteListExpectFailure(alice, flipper.address.toString(), bob.address);
-        });
+      await removeFromContractWhiteListExpectFailure(alice, flipper.address.toString(), bob.address);
     });
+  });
 });

--- a/tests/src/removeFromWhiteList.test.ts
+++ b/tests/src/removeFromWhiteList.test.ts
@@ -28,7 +28,7 @@
   let bob: IKeyringPair;
 
   before(async () => {
-    await usingApi(async (api) => {
+    await usingApi(async () => {
       alice = privateKey('//Alice');
       bob = privateKey('//Bob');
     });
@@ -62,7 +62,7 @@
   let bob: IKeyringPair;
 
   before(async () => {
-    await usingApi(async (api) => {
+    await usingApi(async () => {
       alice = privateKey('//Alice');
       bob = privateKey('//Bob');
     });

--- a/tests/src/rpc.load.ts
+++ b/tests/src/rpc.load.ts
@@ -3,24 +3,22 @@
 // file 'LICENSE', which is part of this source code package.
 //
 
-import { expect, assert } from "chai";
-import usingApi, { submitTransactionAsync, submitTransactionExpectFailAsync } from "./substrate/substrate-api";
-import { IKeyringPair } from "@polkadot/types/types";
-import { Abi, BlueprintPromise as Blueprint, CodePromise, ContractPromise as Contract } from "@polkadot/api-contract";
-import { ApiPromise, Keyring } from "@polkadot/api";
-import { ApiTypes, SubmittableExtrinsic } from "@polkadot/api/types";
+import usingApi, { submitTransactionAsync } from './substrate/substrate-api';
+import { IKeyringPair } from '@polkadot/types/types';
+import { Abi, BlueprintPromise as Blueprint, CodePromise, ContractPromise as Contract } from '@polkadot/api-contract';
+import { ApiPromise, Keyring } from '@polkadot/api';
 import { BigNumber } from 'bignumber.js';
-import { findUnusedAddress } from './util/helpers'
-import fs from "fs";
-import privateKey from "./substrate/privateKey";
+import { findUnusedAddress } from './util/helpers';
+import fs from 'fs';
+import privateKey from './substrate/privateKey';
 
 const value = 0;
 const gasLimit = 500000n * 1000000n;
-const endowment = `1000000000000000`;
-
+const endowment = '1000000000000000';
 
+/*eslint no-async-promise-executor: "off"*/
 function deployBlueprint(alice: IKeyringPair, code: CodePromise): Promise<Blueprint> {
-  return new Promise<Blueprint>(async (resolve, reject) => {
+  return new Promise<Blueprint>(async (resolve) => {
     const unsub = await code
       .createBlueprint()
       .signAndSend(alice, (result) => {
@@ -29,20 +27,21 @@
           resolve(result.blueprint);
           unsub();
         }
-      })
+      });
   });
 }
 
+/*eslint no-async-promise-executor: "off"*/
 function deployContract(alice: IKeyringPair, blueprint: Blueprint) : Promise<any> {
-  return new Promise<any>(async (resolve, reject) => {
+  return new Promise<any>(async (resolve) => {
     const unsub = await blueprint.tx
-    .new(endowment, gasLimit)
-    .signAndSend(alice, (result) => {
-      if (result.status.isInBlock || result.status.isFinalized) {
-        unsub();
-        resolve(result);
-      }
-    });    
+      .new(endowment, gasLimit)
+      .signAndSend(alice, (result) => {
+        if (result.status.isInBlock || result.status.isFinalized) {
+          unsub();
+          resolve(result);
+        }
+      });    
   });
 }
 
@@ -52,7 +51,7 @@
 
   // Transfer balance to it
   const keyring = new Keyring({ type: 'sr25519' });
-  const alice = keyring.addFromUri(`//Alice`);
+  const alice = keyring.addFromUri('//Alice');
   let amount = new BigNumber(endowment);
   amount = amount.plus(1e15);
   const tx = api.tx.balances.transfer(deployer.address, amount.toFixed());
@@ -81,7 +80,7 @@
   const result = await contract.query.get(deployer.address, value, gasLimit);
 
   if(!result.result.isSuccess) {
-    throw `Failed to get value`;
+    throw 'Failed to get value';
   }
   return result.result.asSuccess.data;
 }
@@ -95,6 +94,8 @@
       let microsec1 = hrTime[0] * 1000000 + hrTime[1] / 1000;
       let rate = 0;
       const checkPoint = 1000;
+
+      /* eslint no-constant-condition: "off" */
       while (true) {
         await api.rpc.system.chain();
         count++;
@@ -102,7 +103,7 @@
     
         if (count % checkPoint == 0) {
           hrTime = process.hrtime();
-          let microsec2 = hrTime[0] * 1000000 + hrTime[1] / 1000;
+          const microsec2 = hrTime[0] * 1000000 + hrTime[1] / 1000;
           rate = 1000000*checkPoint/(microsec2 - microsec1);
           microsec1 = microsec2;
         }
@@ -117,7 +118,7 @@
       const [contract, deployer] = await deployLoadTester(api);
 
       // Fill smart contract up with data
-      const bob = privateKey("//Bob");
+      const bob = privateKey('//Bob');
       const tx = contract.tx.bloat(value, gasLimit, 200);
       await submitTransactionAsync(bob, tx);
 
@@ -127,6 +128,8 @@
       let microsec1 = hrTime[0] * 1000000 + hrTime[1] / 1000;
       let rate = 0;
       const checkPoint = 10;
+
+      /* eslint no-constant-condition: "off" */
       while (true) {
         await getScData(contract, deployer);
         count++;
@@ -134,7 +137,7 @@
     
         if (count % checkPoint == 0) {
           hrTime = process.hrtime();
-          let microsec2 = hrTime[0] * 1000000 + hrTime[1] / 1000;
+          const microsec2 = hrTime[0] * 1000000 + hrTime[1] / 1000;
           rate = 1000000*checkPoint/(microsec2 - microsec1);
           microsec1 = microsec2;
         }

--- a/tests/src/scheduler.test.ts
+++ b/tests/src/scheduler.test.ts
@@ -3,7 +3,6 @@
 // file 'LICENSE', which is part of this source code package.
 //
 
-import { IKeyringPair } from '@polkadot/types/types';
 import chai from 'chai';
 import chaiAsPromised from 'chai-as-promised';
 import privateKey from './substrate/privateKey';
@@ -11,34 +10,16 @@
 import {
   createItemExpectSuccess,
   createCollectionExpectSuccess,
-  destroyCollectionExpectSuccess,
-  findNotExistingCollection,
-  queryCollectionExpectSuccess,
-  setOffchainSchemaExpectFailure,
-  setOffchainSchemaExpectSuccess,
-  transferExpectSuccess,
   scheduleTransferExpectSuccess,
   setCollectionSponsorExpectSuccess,
-  confirmSponsorshipExpectSuccess
+  confirmSponsorshipExpectSuccess,
 } from './util/helpers';
-
 
 chai.use(chaiAsPromised);
-const expect = chai.expect;
-
-const DATA = [1, 2, 3, 4];
 
 describe('Integration Test scheduler base transaction', () => {
-  let alice: IKeyringPair;
-
-  before(async () => {
+  it('User can transfer owned token with delay (scheduler)', async () => {
     await usingApi(async () => {
-      alice = privateKey('//Alice');
-    });
-  });
-
-  it('User can transfer owned token with delay (scheduler)', async () => {
-    await usingApi(async (api) => {
       const Alice = privateKey('//Alice');
       const Bob = privateKey('//Bob');
       // nft
@@ -50,45 +31,4 @@
       await scheduleTransferExpectSuccess(nftCollectionId, newNftTokenId, Alice, Bob, 1, 'NFT');
     });
   });
-
-  
 });
-
-// describe('Negative Integration Test setOffchainSchema', () => {
-//   let alice: IKeyringPair;
-//   let bob: IKeyringPair;
-
-//   let validCollectionId: number;
-
-//   before(async () => {
-//     await usingApi(async () => {
-//       alice = privateKey('//Alice');
-//       bob = privateKey('//Bob');
-
-//       validCollectionId = await createCollectionExpectSuccess({ mode: { type: 'NFT' } });
-//     });
-//   });
-
-//   it('fails on not existing collection id', async () => {
-//     const nonExistingCollectionId = await usingApi(findNotExistingCollection);
-
-//     await setOffchainSchemaExpectFailure(alice, nonExistingCollectionId, DATA);
-//   });
-
-//   it('fails on destroyed collection id', async () => {
-//     const destroyedCollectionId = await createCollectionExpectSuccess({ mode: { type: 'NFT' } });
-//     await destroyCollectionExpectSuccess(destroyedCollectionId);
-
-//     await setOffchainSchemaExpectFailure(alice, destroyedCollectionId, DATA);
-//   });
-
-//   it('fails on too long data', async () => {
-//     const tooLongData = new Array(4097).fill(0xff);
-
-//     await setOffchainSchemaExpectFailure(alice, validCollectionId, tooLongData);
-//   });
-
-//   it('fails on execution by non-owner', async () => {
-//     await setOffchainSchemaExpectFailure(bob, validCollectionId, DATA);
-//   });
-// });

--- a/tests/src/setCollectionLimits.test.ts
+++ b/tests/src/setCollectionLimits.test.ts
@@ -50,7 +50,7 @@
           TokenLimit: tokenLimit,
           SponsorTimeout: sponsorTimeout,
           OwnerCanTransfer: true,
-          OwnerCanDestroy: true
+          OwnerCanDestroy: true,
         },
       );
       const events = await submitTransactionAsync(alice, tx);
@@ -73,13 +73,13 @@
   it('Set the same token limit twice', async () => {
     await usingApi(async (api: ApiPromise) => {
 
-      let collectionLimits = {
+      const collectionLimits = {
         AccountTokenOwnershipLimit: accountTokenOwnershipLimit,
         SponsoredMintSize: sponsoredDataSize,
         TokenLimit: tokenLimit,
         SponsorTimeout: sponsorTimeout,
         OwnerCanTransfer: true,
-        OwnerCanDestroy: true
+        OwnerCanDestroy: true,
       };
 
       // The first time
@@ -173,7 +173,7 @@
       TokenLimit: tokenLimit,
       SponsorTimeout: sponsorTimeout,
       OwnerCanTransfer: false,
-      OwnerCanDestroy: true
+      OwnerCanDestroy: true,
     });
     await setCollectionLimitsExpectFailure(alice, collectionId, { 
       AccountTokenOwnershipLimit: accountTokenOwnershipLimit,
@@ -181,7 +181,7 @@
       TokenLimit: tokenLimit,
       SponsorTimeout: sponsorTimeout,
       OwnerCanTransfer: true,
-      OwnerCanDestroy: true
+      OwnerCanDestroy: true,
     });
   });
 
@@ -193,7 +193,7 @@
       TokenLimit: tokenLimit,
       SponsorTimeout: sponsorTimeout,
       OwnerCanTransfer: true,
-      OwnerCanDestroy: false
+      OwnerCanDestroy: false,
     });
     await setCollectionLimitsExpectFailure(alice, collectionId, { 
       AccountTokenOwnershipLimit: accountTokenOwnershipLimit,
@@ -201,21 +201,21 @@
       TokenLimit: tokenLimit,
       SponsorTimeout: sponsorTimeout,
       OwnerCanTransfer: true,
-      OwnerCanDestroy: true
+      OwnerCanDestroy: true,
     });
   });
 
   it('Setting the higher token limit fails', async () => {
-    await usingApi(async (api: ApiPromise) => {
+    await usingApi(async () => {
 
       const collectionId = await createCollectionExpectSuccess();
-      let collectionLimits = {
+      const collectionLimits = {
         AccountTokenOwnershipLimit: accountTokenOwnershipLimit,
         SponsoredMintSize: sponsoredDataSize,
         TokenLimit: tokenLimit,
         SponsorTimeout: sponsorTimeout,
         OwnerCanTransfer: true,
-        OwnerCanDestroy: true
+        OwnerCanDestroy: true,
       };
 
       // The first time

--- a/tests/src/setCollectionSponsor.test.ts
+++ b/tests/src/setCollectionSponsor.test.ts
@@ -5,22 +5,21 @@
 
 import chai from 'chai';
 import chaiAsPromised from 'chai-as-promised';
-import { default as usingApi } from "./substrate/substrate-api";
-import { createCollectionExpectSuccess, setCollectionSponsorExpectSuccess, destroyCollectionExpectSuccess, setCollectionSponsorExpectFailure } from "./util/helpers";
-import { Keyring } from "@polkadot/api";
-import { IKeyringPair } from "@polkadot/types/types";
+import { default as usingApi } from './substrate/substrate-api';
+import { createCollectionExpectSuccess, setCollectionSponsorExpectSuccess, destroyCollectionExpectSuccess, setCollectionSponsorExpectFailure } from './util/helpers';
+import { Keyring } from '@polkadot/api';
+import { IKeyringPair } from '@polkadot/types/types';
 
 chai.use(chaiAsPromised);
-const expect = chai.expect;
 
 let bob: IKeyringPair;
 
 describe('integration test: ext. setCollectionSponsor():', () => {
 
   before(async () => {
-    await usingApi(async (api) => {
+    await usingApi(async () => {
       const keyring = new Keyring({ type: 'sr25519' });
-      bob = keyring.addFromUri(`//Bob`);
+      bob = keyring.addFromUri('//Bob');
     });
   });
 
@@ -46,7 +45,7 @@
     const collectionId = await createCollectionExpectSuccess();
 
     const keyring = new Keyring({ type: 'sr25519' });
-    const charlie = keyring.addFromUri(`//Charlie`);
+    const charlie = keyring.addFromUri('//Charlie');
     await setCollectionSponsorExpectSuccess(collectionId, bob.address);
     await setCollectionSponsorExpectSuccess(collectionId, charlie.address);
   });
@@ -54,9 +53,9 @@
 
 describe('(!negative test!) integration test: ext. setCollectionSponsor():', () => {
   before(async () => {
-    await usingApi(async (api) => {
+    await usingApi(async () => {
       const keyring = new Keyring({ type: 'sr25519' });
-      bob = keyring.addFromUri(`//Bob`);
+      bob = keyring.addFromUri('//Bob');
     });
   });
 
@@ -66,9 +65,9 @@
   });
   it('(!negative test!) Add sponsor to a collection that never existed', async () => {
     // Find the collection that never existed
-    const collectionId = 0;
+    let collectionId = 0;
     await usingApi(async (api) => {
-      const collectionId = parseInt((await api.query.nft.createdCollectionCount()).toString()) + 1;
+      collectionId = parseInt((await api.query.nft.createdCollectionCount()).toString()) + 1;
     });
 
     await setCollectionSponsorExpectFailure(collectionId, bob.address);

--- a/tests/src/setConstOnChainSchema.test.ts
+++ b/tests/src/setConstOnChainSchema.test.ts
@@ -23,7 +23,7 @@
 let largeShema: any;
 
 before(async () => {
-  await usingApi(async (api) => {
+  await usingApi(async () => {
     const keyring = new Keyring({ type: 'sr25519' });
     Alice = keyring.addFromUri('//Alice');
     Bob = keyring.addFromUri('//Bob');
@@ -35,7 +35,7 @@
 describe('Integration Test ext. setConstOnChainSchema()', () => {
 
   it('Run extrinsic with parameters of the collection id, set the scheme', async () => {
-      await usingApi(async (api) => {
+    await usingApi(async (api) => {
       const collectionId = await createCollectionExpectSuccess();
       const collection: any = (await api.query.nft.collectionById(collectionId)).toJSON();
       expect(collection.Owner).to.be.deep.eq(normalizeAccountId(Alice.address));
@@ -45,12 +45,12 @@
   });
 
   it('Checking collection data using the ConstOnChainSchema parameter', async () => {
-      await usingApi(async (api) => {
-        const collectionId = await createCollectionExpectSuccess();
-        const setShema = api.tx.nft.setConstOnChainSchema(collectionId, Shema);
-        await submitTransactionAsync(Alice, setShema);
-        const collection: any = (await api.query.nft.collectionById(collectionId)).toJSON();
-        expect(collection.ConstOnChainSchema.toString()).to.be.eq(Shema);
+    await usingApi(async (api) => {
+      const collectionId = await createCollectionExpectSuccess();
+      const setShema = api.tx.nft.setConstOnChainSchema(collectionId, Shema);
+      await submitTransactionAsync(Alice, setShema);
+      const collection: any = (await api.query.nft.collectionById(collectionId)).toJSON();
+      expect(collection.ConstOnChainSchema.toString()).to.be.eq(Shema);
 
     });
   });

--- a/tests/src/setContractSponsoringRateLimit.test.ts
+++ b/tests/src/setContractSponsoringRateLimit.test.ts
@@ -59,7 +59,7 @@
 
   it('fails when called by non-owning user', async () => {
     await usingApi(async (api) => {
-      const [flipper, _] = await deployFlipper(api);
+      const [flipper] = await deployFlipper(api);
 
       await setContractSponsoringRateLimitExpectFailure(alice, flipper.address, 1);
     });

--- a/tests/src/setPublicAccessMode.test.ts
+++ b/tests/src/setPublicAccessMode.test.ts
@@ -1,95 +1,94 @@
-//
-// This file is subject to the terms and conditions defined in
-// file 'LICENSE', which is part of this source code package.
-//
-
-// https://unique-network.readthedocs.io/en/latest/jsapi.html#setschemaversion
-import { ApiPromise, Keyring } from '@polkadot/api';
-import { IKeyringPair } from '@polkadot/types/types';
-import chai from 'chai';
-import chaiAsPromised from 'chai-as-promised';
-import privateKey from './substrate/privateKey';
-import usingApi, {submitTransactionExpectFailAsync} from './substrate/substrate-api';
-import {
-  addToWhiteListExpectSuccess,
-  createCollectionExpectSuccess,
-  createItemExpectSuccess,
-  destroyCollectionExpectSuccess,
-  enablePublicMintingExpectSuccess,
-  enableWhiteListExpectSuccess,
-  normalizeAccountId,
-} from './util/helpers';
-import { utf16ToStr } from './util/util';
-
-chai.use(chaiAsPromised);
-const expect = chai.expect;
-
-let Alice: IKeyringPair;
-let Bob: IKeyringPair;
-
-describe('Integration Test setPublicAccessMode(): ', () => {
-  before(async () => {
-    await usingApi(async (api) => {
-      Alice = privateKey('//Alice');
-      Bob = privateKey('//Bob');
-    });
-  });
-
-  it('Run extrinsic with collection id parameters, set the whitelist mode for the collection', async () => {
-    await usingApi(async (api: ApiPromise) => {
-      const collectionId: number = await createCollectionExpectSuccess();
-      await enableWhiteListExpectSuccess(Alice, collectionId);
-      await enablePublicMintingExpectSuccess(Alice, collectionId);
-      await addToWhiteListExpectSuccess(Alice, collectionId, Bob.address);
-      await createItemExpectSuccess(Bob, collectionId, 'NFT', Bob.address);
-    });
-  });
-
-  it('Whitelisted collection limits', async () => {
-    await usingApi(async (api: ApiPromise) => {
-      const collectionId = await createCollectionExpectSuccess();
-      await enableWhiteListExpectSuccess(Alice, collectionId);
-      await enablePublicMintingExpectSuccess(Alice, collectionId);
-      const tx = api.tx.nft.createItem(collectionId, normalizeAccountId(Bob.address), 'NFT');
-      await expect(submitTransactionExpectFailAsync(Bob, tx)).to.be.rejected;
-    });
-  });
-});
-
-describe('Negative Integration Test ext. setPublicAccessMode(): ', () => {
-  it('Set a non-existent collection', async () => {
-    await usingApi(async (api: ApiPromise) => {
-      // tslint:disable-next-line: radix
-      const collectionId = parseInt((await api.query.nft.createdCollectionCount()).toString()) + 1;
-      const tx = api.tx.nft.setPublicAccessMode(collectionId, 'WhiteList');
-      await expect(submitTransactionExpectFailAsync(Alice, tx)).to.be.rejected;
-    });
-  });
-
-  it('Set the collection that has been deleted', async () => {
-    await usingApi(async (api: ApiPromise) => {
-      // tslint:disable-next-line: no-bitwise
-      const collectionId = await createCollectionExpectSuccess();
-      await destroyCollectionExpectSuccess(collectionId);
-      const tx = api.tx.nft.setPublicAccessMode(collectionId, 'WhiteList');
-      await expect(submitTransactionExpectFailAsync(Alice, tx)).to.be.rejected;
-    });
-  });
-
-  it('Re-set the list mode already set in quantity', async () => {
-    await usingApi(async (api: ApiPromise) => {
-      const collectionId: number = await createCollectionExpectSuccess();
-      await enableWhiteListExpectSuccess(Alice, collectionId);
-      await enableWhiteListExpectSuccess(Alice, collectionId);
-    });
-  });
-
-  it('Execute method not on behalf of the collection owner', async () => {
-    await usingApi(async (api: ApiPromise) => {
-      // tslint:disable-next-line: no-bitwise
-      const collectionId = await createCollectionExpectSuccess();
-      const tx = api.tx.nft.setPublicAccessMode(collectionId, 'WhiteList');
-      await expect(submitTransactionExpectFailAsync(Bob, tx)).to.be.rejected;
-    });
-  });
-});
+//
+// This file is subject to the terms and conditions defined in
+// file 'LICENSE', which is part of this source code package.
+//
+
+// https://unique-network.readthedocs.io/en/latest/jsapi.html#setschemaversion
+import { ApiPromise } from '@polkadot/api';
+import { IKeyringPair } from '@polkadot/types/types';
+import chai from 'chai';
+import chaiAsPromised from 'chai-as-promised';
+import privateKey from './substrate/privateKey';
+import usingApi, {submitTransactionExpectFailAsync} from './substrate/substrate-api';
+import {
+  addToWhiteListExpectSuccess,
+  createCollectionExpectSuccess,
+  createItemExpectSuccess,
+  destroyCollectionExpectSuccess,
+  enablePublicMintingExpectSuccess,
+  enableWhiteListExpectSuccess,
+  normalizeAccountId,
+} from './util/helpers';
+
+chai.use(chaiAsPromised);
+const expect = chai.expect;
+
+let Alice: IKeyringPair;
+let Bob: IKeyringPair;
+
+describe('Integration Test setPublicAccessMode(): ', () => {
+  before(async () => {
+    await usingApi(async () => {
+      Alice = privateKey('//Alice');
+      Bob = privateKey('//Bob');
+    });
+  });
+
+  it('Run extrinsic with collection id parameters, set the whitelist mode for the collection', async () => {
+    await usingApi(async () => {
+      const collectionId: number = await createCollectionExpectSuccess();
+      await enableWhiteListExpectSuccess(Alice, collectionId);
+      await enablePublicMintingExpectSuccess(Alice, collectionId);
+      await addToWhiteListExpectSuccess(Alice, collectionId, Bob.address);
+      await createItemExpectSuccess(Bob, collectionId, 'NFT', Bob.address);
+    });
+  });
+
+  it('Whitelisted collection limits', async () => {
+    await usingApi(async (api: ApiPromise) => {
+      const collectionId = await createCollectionExpectSuccess();
+      await enableWhiteListExpectSuccess(Alice, collectionId);
+      await enablePublicMintingExpectSuccess(Alice, collectionId);
+      const tx = api.tx.nft.createItem(collectionId, normalizeAccountId(Bob.address), 'NFT');
+      await expect(submitTransactionExpectFailAsync(Bob, tx)).to.be.rejected;
+    });
+  });
+});
+
+describe('Negative Integration Test ext. setPublicAccessMode(): ', () => {
+  it('Set a non-existent collection', async () => {
+    await usingApi(async (api: ApiPromise) => {
+      // tslint:disable-next-line: radix
+      const collectionId = parseInt((await api.query.nft.createdCollectionCount()).toString()) + 1;
+      const tx = api.tx.nft.setPublicAccessMode(collectionId, 'WhiteList');
+      await expect(submitTransactionExpectFailAsync(Alice, tx)).to.be.rejected;
+    });
+  });
+
+  it('Set the collection that has been deleted', async () => {
+    await usingApi(async (api: ApiPromise) => {
+      // tslint:disable-next-line: no-bitwise
+      const collectionId = await createCollectionExpectSuccess();
+      await destroyCollectionExpectSuccess(collectionId);
+      const tx = api.tx.nft.setPublicAccessMode(collectionId, 'WhiteList');
+      await expect(submitTransactionExpectFailAsync(Alice, tx)).to.be.rejected;
+    });
+  });
+
+  it('Re-set the list mode already set in quantity', async () => {
+    await usingApi(async () => {
+      const collectionId: number = await createCollectionExpectSuccess();
+      await enableWhiteListExpectSuccess(Alice, collectionId);
+      await enableWhiteListExpectSuccess(Alice, collectionId);
+    });
+  });
+
+  it('Execute method not on behalf of the collection owner', async () => {
+    await usingApi(async (api: ApiPromise) => {
+      // tslint:disable-next-line: no-bitwise
+      const collectionId = await createCollectionExpectSuccess();
+      const tx = api.tx.nft.setPublicAccessMode(collectionId, 'WhiteList');
+      await expect(submitTransactionExpectFailAsync(Bob, tx)).to.be.rejected;
+    });
+  });
+});

--- a/tests/src/setSchemaVersion.test.ts
+++ b/tests/src/setSchemaVersion.test.ts
@@ -103,7 +103,7 @@
   it('execute setSchemaVersion with not correct schema version', async () => {
     await usingApi(async (api: ApiPromise) => {
       const consoleError = console.error;
-      console.error = (message: string) => {};
+      console.error = () => {};
       try {
         tx = api.tx.nft.setSchemaVersion(collectionIdForTesting, 'Test');
         await submitTransactionAsync(alice, tx);

--- a/tests/src/setVariableMetaData.test.ts
+++ b/tests/src/setVariableMetaData.test.ts
@@ -49,7 +49,7 @@
 });
 
 describe('Negative Integration Test setVariableMetaData', () => {
-  let data = [1];
+  const data = [1];
 
   let alice: IKeyringPair;
   let bob: IKeyringPair;
@@ -69,7 +69,7 @@
 
   it('fails on not existing collection id', async () => {
     await usingApi(async api => {
-      let nonExistingCollectionId = await findNotExistingCollection(api);
+      const nonExistingCollectionId = await findNotExistingCollection(api);
       await setVariableMetaDataExpectFailure(alice, nonExistingCollectionId, 1, data);
     });
   });

--- a/tests/src/setVariableOnChainSchema.test.ts
+++ b/tests/src/setVariableOnChainSchema.test.ts
@@ -23,7 +23,7 @@
 let largeSchema: any;
 
 before(async () => {
-  await usingApi(async (api) => {
+  await usingApi(async () => {
     const keyring = new Keyring({ type: 'sr25519' });
     Alice = keyring.addFromUri('//Alice');
     Bob = keyring.addFromUri('//Bob');
@@ -35,7 +35,7 @@
 describe('Integration Test ext. setVariableOnChainSchema()', () => {
 
   it('Run extrinsic with parameters of the collection id, set the scheme', async () => {
-      await usingApi(async (api) => {
+    await usingApi(async (api) => {
       const collectionId = await createCollectionExpectSuccess();
       const collection: any = (await api.query.nft.collectionById(collectionId)).toJSON();
       expect(collection.Owner).to.be.deep.eq(normalizeAccountId(Alice.address));
@@ -45,12 +45,12 @@
   });
 
   it('Checking collection data using the setVariableOnChainSchema parameter', async () => {
-      await usingApi(async (api) => {
-        const collectionId = await createCollectionExpectSuccess();
-        const setSchema = api.tx.nft.setVariableOnChainSchema(collectionId, Schema);
-        await submitTransactionAsync(Alice, setSchema);
-        const collection: any = (await api.query.nft.collectionById(collectionId)).toJSON();
-        expect(collection.VariableOnChainSchema.toString()).to.be.eq(Schema);
+    await usingApi(async (api) => {
+      const collectionId = await createCollectionExpectSuccess();
+      const setSchema = api.tx.nft.setVariableOnChainSchema(collectionId, Schema);
+      await submitTransactionAsync(Alice, setSchema);
+      const collection: any = (await api.query.nft.collectionById(collectionId)).toJSON();
+      expect(collection.VariableOnChainSchema.toString()).to.be.eq(Schema);
 
     });
   });

--- a/tests/src/substrate/privateKey.ts
+++ b/tests/src/substrate/privateKey.ts
@@ -3,8 +3,8 @@
 // file 'LICENSE', which is part of this source code package.
 //
 
-import { Keyring } from "@polkadot/api";
-import { IKeyringPair } from "@polkadot/types/types";
+import { Keyring } from '@polkadot/api';
+import { IKeyringPair } from '@polkadot/types/types';
 
 export default function privateKey(account: string): IKeyringPair {
   const keyring = new Keyring({ type: 'sr25519' });

--- a/tests/src/substrate/promisify-substrate.ts
+++ b/tests/src/substrate/promisify-substrate.ts
@@ -3,7 +3,7 @@
 // file 'LICENSE', which is part of this source code package.
 //
 
-import { ApiPromise } from "@polkadot/api";
+import { ApiPromise } from '@polkadot/api';
 
 type PromiseType<T> = T extends PromiseLike<infer TInner> ? TInner : T;
 

--- a/tests/src/substrate/substrate-api.ts
+++ b/tests/src/substrate/substrate-api.ts
@@ -3,15 +3,15 @@
 // file 'LICENSE', which is part of this source code package.
 //
 
-import { WsProvider, ApiPromise } from "@polkadot/api";
+import { WsProvider, ApiPromise } from '@polkadot/api';
 import { EventRecord } from '@polkadot/types/interfaces/system/types';
 import { ExtrinsicStatus } from '@polkadot/types/interfaces/author/types';
-import { IKeyringPair } from "@polkadot/types/types";
+import { IKeyringPair } from '@polkadot/types/types';
 
-import config from "../config";
-import promisifySubstrate from "./promisify-substrate";
-import { ApiOptions, SubmittableExtrinsic, ApiTypes } from "@polkadot/api/types";
-import rtt from "../../../runtime_types.json";
+import config from '../config';
+import promisifySubstrate from './promisify-substrate';
+import { ApiOptions, SubmittableExtrinsic, ApiTypes } from '@polkadot/api/types';
+import rtt from '../../../runtime_types.json';
 
 function defaultApiOptions(): ApiOptions {
   const wsProvider = new WsProvider(config.substrateUrl);
@@ -20,15 +20,15 @@
 
 export default async function usingApi<T = void>(action: (api: ApiPromise) => Promise<T>, settings: ApiOptions | undefined = undefined): Promise<T> {
   settings = settings || defaultApiOptions();
-  let api: ApiPromise = new ApiPromise(settings);
+  const api: ApiPromise = new ApiPromise(settings);
   let result: T = null as unknown as T;
 
   // TODO: Remove, this is temporary: Filter unneeded API output 
   // (Jaco promised it will be removed in the next version)
   const consoleErr = console.error;
   console.error = (message: string) => {
-    if (message.includes("StorageChangeSet:: WebSocket is not connected") || message.includes("2021-")) {}
-    else consoleErr(message);
+    if (!message.includes('StorageChangeSet:: WebSocket is not connected') || message.includes('2021-'))
+      consoleErr(message);
   };
 
   try {
@@ -72,6 +72,7 @@
 
 export function
 submitTransactionAsync(sender: IKeyringPair, transaction: SubmittableExtrinsic<ApiTypes>): Promise<EventRecord[]> {
+  /* eslint no-async-promise-executor: "off" */
   return new Promise(async (resolve, reject) => {
     try {
       await transaction.signAndSend(sender, ({ events = [], status }) => {
@@ -97,6 +98,7 @@
   console.error = () => {};
   console.log = () => {};
 
+  /* eslint no-async-promise-executor: "off" */
   return new Promise<EventRecord[]>(async function(res, rej) {
     const resolve = (rec: EventRecord[]) => {
       setTimeout(() => {

--- a/tests/src/substrate/wait-new-blocks.ts
+++ b/tests/src/substrate/wait-new-blocks.ts
@@ -3,15 +3,16 @@
 // file 'LICENSE', which is part of this source code package.
 //
 
-import { ApiPromise } from "@polkadot/api";
+import { ApiPromise } from '@polkadot/api';
 
-export default function waitNewBlocks(api: ApiPromise, blocksCount: number = 1): Promise<void> {
-  const promise = new Promise<void>(async (resolve, reject) => {
+/* eslint no-async-promise-executor: "off" */
+export default function waitNewBlocks(api: ApiPromise, blocksCount = 1): Promise<void> {
+  const promise = new Promise<void>(async (resolve) => {
     
-    const unsubscribe = await api.rpc.chain.subscribeNewHeads(head => {
-      if(blocksCount > 0) {
+    const unsubscribe = await api.rpc.chain.subscribeNewHeads(() => {
+      if (blocksCount > 0) {
         blocksCount--;
-      }else {
+      } else {
         unsubscribe();
         resolve();
       }

--- a/tests/src/toggleContractWhiteList.test.ts
+++ b/tests/src/toggleContractWhiteList.test.ts
@@ -3,17 +3,17 @@
 // file 'LICENSE', which is part of this source code package.
 //
 
-import chai from "chai";
+import chai from 'chai';
 import chaiAsPromised from 'chai-as-promised';
-import usingApi, { submitTransactionAsync, submitTransactionExpectFailAsync } from "./substrate/substrate-api";
-import privateKey from "./substrate/privateKey";
+import usingApi, { submitTransactionAsync, submitTransactionExpectFailAsync } from './substrate/substrate-api';
+import privateKey from './substrate/privateKey';
 import {
   deployFlipper,
-  getFlipValue
-} from "./util/contracthelpers";
+  getFlipValue,
+} from './util/contracthelpers';
 import {
-  getGenericResult
-} from "./util/helpers"
+  getGenericResult,
+} from './util/helpers';
 
 chai.use(chaiAsPromised);
 const expect = chai.expect;
@@ -23,7 +23,7 @@
 
 describe('Integration Test toggleContractWhiteList', () => {
 
-  it(`Enable white list contract mode`, async () => {
+  it('Enable white list contract mode', async () => {
     await usingApi(async api => {
       const [contract, deployer] = await deployFlipper(api);
 
@@ -38,9 +38,9 @@
     });
   });
 
-  it(`Only whitelisted account can call contract`, async () => {
+  it('Only whitelisted account can call contract', async () => {
     await usingApi(async api => {
-      const bob = privateKey("//Bob");
+      const bob = privateKey('//Bob');
 
       const [contract, deployer] = await deployFlipper(api);
 
@@ -48,59 +48,59 @@
       const flip = contract.exec('flip', value, gasLimit);
       await submitTransactionAsync(bob, flip);
       const flipValueAfter = await getFlipValue(contract,deployer);
-      expect(flipValueAfter).to.be.eq(!flipValueBefore, `Anyone can call new contract.`);
+      expect(flipValueAfter).to.be.eq(!flipValueBefore, 'Anyone can call new contract.');
 
       const deployerCanFlip = async () => {
-        let flipValueBefore = await getFlipValue(contract, deployer);
+        const flipValueBefore = await getFlipValue(contract, deployer);
         const deployerFlip = contract.exec('flip', value, gasLimit);
         await submitTransactionAsync(deployer, deployerFlip);
         const aliceFlip1Response = await getFlipValue(contract, deployer);
-        expect(aliceFlip1Response).to.be.eq(!flipValueBefore, `Deployer always can flip.`);
+        expect(aliceFlip1Response).to.be.eq(!flipValueBefore, 'Deployer always can flip.');
       };
       await deployerCanFlip();
 
       flipValueBefore = await getFlipValue(contract, deployer);
       const enableWhiteListTx = api.tx.nft.toggleContractWhiteList(contract.address, true);
-      const enableResult = await submitTransactionAsync(deployer, enableWhiteListTx);
+      await submitTransactionAsync(deployer, enableWhiteListTx);
       const flipWithEnabledWhiteList = contract.exec('flip', value, gasLimit);
       await expect(submitTransactionExpectFailAsync(bob, flipWithEnabledWhiteList)).to.be.rejected;
       const flipValueAfterEnableWhiteList = await getFlipValue(contract, deployer);
-      expect(flipValueAfterEnableWhiteList).to.be.eq(flipValueBefore, `Enabling whitelist doesn't make it possible to call contract for everyone.`);
+      expect(flipValueAfterEnableWhiteList).to.be.eq(flipValueBefore, 'Enabling whitelist doesn\'t make it possible to call contract for everyone.');
 
       await deployerCanFlip();
 
       flipValueBefore = await getFlipValue(contract, deployer);
       const addBobToWhiteListTx = api.tx.nft.addToContractWhiteList(contract.address, bob.address);
-      const addBobResult = await submitTransactionAsync(deployer, addBobToWhiteListTx);
+      await submitTransactionAsync(deployer, addBobToWhiteListTx);
       const flipWithWhitelistedBob = contract.exec('flip', value, gasLimit);
       await submitTransactionAsync(bob, flipWithWhitelistedBob);
       const flipAfterWhiteListed = await getFlipValue(contract,deployer);
-      expect(flipAfterWhiteListed).to.be.eq(!flipValueBefore, `Bob was whitelisted, now he can flip.`);
+      expect(flipAfterWhiteListed).to.be.eq(!flipValueBefore, 'Bob was whitelisted, now he can flip.');
 
       await deployerCanFlip();
 
       flipValueBefore = await getFlipValue(contract, deployer);
       const removeBobFromWhiteListTx = api.tx.nft.removeFromContractWhiteList(contract.address, bob.address);
-      const removeBobResult = await submitTransactionAsync(deployer, removeBobFromWhiteListTx);
+      await submitTransactionAsync(deployer, removeBobFromWhiteListTx);
       const bobRemoved = contract.exec('flip', value, gasLimit);
       await expect(submitTransactionExpectFailAsync(bob, bobRemoved)).to.be.rejected;
       const afterBobRemoved = await getFlipValue(contract, deployer);
-      expect(afterBobRemoved).to.be.eq(flipValueBefore, `Bob can't call contract, now when he is removeed from white list.`);
+      expect(afterBobRemoved).to.be.eq(flipValueBefore, 'Bob can\'t call contract, now when he is removeed from white list.');
 
       await deployerCanFlip();
 
       flipValueBefore = await getFlipValue(contract, deployer);
       const disableWhiteListTx = api.tx.nft.toggleContractWhiteList(contract.address, false);
-      const disableWhiteListResult = await submitTransactionAsync(deployer, disableWhiteListTx);
+      await submitTransactionAsync(deployer, disableWhiteListTx);
       const whiteListDisabledFlip = contract.exec('flip', value, gasLimit);
       await submitTransactionAsync(bob, whiteListDisabledFlip);
       const afterWhiteListDisabled = await getFlipValue(contract,deployer);
-      expect(afterWhiteListDisabled).to.be.eq(!flipValueBefore, `Anyone can call contract with disabled whitelist.`);
+      expect(afterWhiteListDisabled).to.be.eq(!flipValueBefore, 'Anyone can call contract with disabled whitelist.');
 
     });
   });
 
-  it(`Enabling white list repeatedly should not produce errors`, async () => {
+  it('Enabling white list repeatedly should not produce errors', async () => {
     await usingApi(async api => {
       const [contract, deployer] = await deployFlipper(api);
 
@@ -123,10 +123,10 @@
 
 describe('Negative Integration Test toggleContractWhiteList', () => {
 
-  it(`Enable white list for a non-contract`, async () => {
+  it('Enable white list for a non-contract', async () => {
     await usingApi(async api => {
-      const alice = privateKey("//Alice");
-      const bobGuineaPig = privateKey("//Bob");
+      const alice = privateKey('//Alice');
+      const bobGuineaPig = privateKey('//Bob');
 
       const enabledBefore = (await api.query.nft.contractWhiteListEnabled(bobGuineaPig.address)).toJSON();
       const enableWhiteListTx = api.tx.nft.toggleContractWhiteList(bobGuineaPig.address, true);
@@ -138,10 +138,10 @@
     });
   });
 
-  it(`Enable white list using a non-owner address`, async () => {
+  it('Enable white list using a non-owner address', async () => {
     await usingApi(async api => {
-      const bob = privateKey("//Bob");
-      const [contract, deployer] = await deployFlipper(api);
+      const bob = privateKey('//Bob');
+      const [contract] = await deployFlipper(api);
 
       const enabledBefore = (await api.query.nft.contractWhiteListEnabled(contract.address)).toJSON();
       const enableWhiteListTx = api.tx.nft.toggleContractWhiteList(contract.address, true);

--- a/tests/src/transfer.nload.ts
+++ b/tests/src/transfer.nload.ts
@@ -1,9 +1,14 @@
-import { ApiPromise } from "@polkadot/api";
+//
+// This file is subject to the terms and conditions defined in
+// file 'LICENSE', which is part of this source code package.
+//
+
+import { ApiPromise } from '@polkadot/api';
 import { IKeyringPair } from '@polkadot/types/types';
-import privateKey from "./substrate/privateKey";
-import usingApi, { submitTransactionAsync } from "./substrate/substrate-api";
-import waitNewBlocks from "./substrate/wait-new-blocks";
-import { findUnusedAddresses } from "./util/helpers";
+import privateKey from './substrate/privateKey';
+import usingApi, { submitTransactionAsync } from './substrate/substrate-api';
+import waitNewBlocks from './substrate/wait-new-blocks';
+import { findUnusedAddresses } from './util/helpers';
 import * as cluster from 'cluster';
 import os from 'os';
 
@@ -12,102 +17,102 @@
 
 let counters: { [key: string]: number } = {};
 function increaseCounter(name: string, amount: number) {
-    if (!counters[name]) {
-        counters[name] = 0;
-    }
-    counters[name] += amount;
+  if (!counters[name]) {
+    counters[name] = 0;
+  }
+  counters[name] += amount;
 }
 function flushCounterToMaster() {
-    if (Object.keys(counters).length === 0) {
-        return;
-    }
+  if (Object.keys(counters).length === 0) {
+    return;
+  }
     process.send!(counters);
     counters = {};
 }
 
 async function distributeBalance(source: IKeyringPair, api: ApiPromise, totalAmount: bigint, stages: number) {
-    let accounts = [source];
-    // we don't need source in output array
-    const failedAccounts = [0];
+  const accounts = [source];
+  // we don't need source in output array
+  const failedAccounts = [0];
 
-    const finalUserAmount = 2 ** stages - 1;
-    accounts.push(...await findUnusedAddresses(api, finalUserAmount));
-    // findUnusedAddresses produces at least 1 request per user
-    increaseCounter('requests', finalUserAmount);
+  const finalUserAmount = 2 ** stages - 1;
+  accounts.push(...await findUnusedAddresses(api, finalUserAmount));
+  // findUnusedAddresses produces at least 1 request per user
+  increaseCounter('requests', finalUserAmount);
 
-    for (let stage = 0; stage < stages; stage++) {
-        let usersWithBalance = 2 ** stage;
-        let amount = totalAmount / (2n ** BigInt(stage)) - FEE * BigInt(stage);
-        // console.log(`Stage ${stage}/${stages}, ${usersWithBalance} => ${usersWithBalance * 2} = ${amount}`);
-        let txs = [];
-        for (let i = 0; i < usersWithBalance; i++) {
-            let newUser = accounts[i + usersWithBalance];
-            // console.log(`${accounts[i].address} => ${newUser.address} = ${amountToSplit}`);
-            const tx = api.tx.balances.transfer(newUser.address, amount);
-            txs.push(submitTransactionAsync(accounts[i], tx).catch(e => {
-                failedAccounts.push(i + usersWithBalance);
-                increaseCounter('txFailed', 1);
-            }));
-            increaseCounter('tx', 1);
-        }
-        await Promise.all(txs);
+  for (let stage = 0; stage < stages; stage++) {
+    const usersWithBalance = 2 ** stage;
+    const amount = totalAmount / (2n ** BigInt(stage)) - FEE * BigInt(stage);
+    // console.log(`Stage ${stage}/${stages}, ${usersWithBalance} => ${usersWithBalance * 2} = ${amount}`);
+    const txs = [];
+    for (let i = 0; i < usersWithBalance; i++) {
+      const newUser = accounts[i + usersWithBalance];
+      // console.log(`${accounts[i].address} => ${newUser.address} = ${amountToSplit}`);
+      const tx = api.tx.balances.transfer(newUser.address, amount);
+      txs.push(submitTransactionAsync(accounts[i], tx).catch(() => {
+        failedAccounts.push(i + usersWithBalance);
+        increaseCounter('txFailed', 1);
+      }));
+      increaseCounter('tx', 1);
     }
+    await Promise.all(txs);
+  }
 
-    for (let account of failedAccounts.reverse()) {
-        accounts.splice(account, 1);
-    }
-    return accounts;
+  for (const account of failedAccounts.reverse()) {
+    accounts.splice(account, 1);
+  }
+  return accounts;
 }
 
 if (cluster.isMaster) {
-    let testDone = false;
-    usingApi(async (api) => {
-        let prevCounters: { [key: string]: number } = {};
-        while (!testDone) {
-            for (let name in counters) {
-                if (!(name in prevCounters)) {
-                    prevCounters[name] = 0;
-                }
-                if(counters[name] === prevCounters[name]) {
-                    continue;
-                }
-                console.log(`${name.padEnd(15)} = ${counters[name] - prevCounters[name]}`);
-                prevCounters[name] = counters[name];
-            }
-            await waitNewBlocks(api, 1);
+  let testDone = false;
+  usingApi(async (api) => {
+    const prevCounters: { [key: string]: number } = {};
+    while (!testDone) {
+      for (const name in counters) {
+        if (!(name in prevCounters)) {
+          prevCounters[name] = 0;
+        }
+        if(counters[name] === prevCounters[name]) {
+          continue;
         }
-    });
-    let waiting: Promise<void>[] = [];
-    console.log(`Starting ${os.cpus().length} workers`);
-    usingApi(async (api) => {
-        const alice = privateKey('//Alice');
-        for (let id in os.cpus()) {
-            const WORKER_NAME = `//LoadWorker${id}_${Date.now()}`;
-            const workerAccount = privateKey(WORKER_NAME);
-            const tx = api.tx.balances.transfer(workerAccount.address, 400n * 10n ** 23n);
-            await submitTransactionAsync(alice, tx);
+        console.log(`${name.padEnd(15)} = ${counters[name] - prevCounters[name]}`);
+        prevCounters[name] = counters[name];
+      }
+      await waitNewBlocks(api, 1);
+    }
+  });
+  const waiting: Promise<void>[] = [];
+  console.log(`Starting ${os.cpus().length} workers`);
+  usingApi(async (api) => {
+    const alice = privateKey('//Alice');
+    for (const id in os.cpus()) {
+      const WORKER_NAME = `//LoadWorker${id}_${Date.now()}`;
+      const workerAccount = privateKey(WORKER_NAME);
+      const tx = api.tx.balances.transfer(workerAccount.address, 400n * 10n ** 23n);
+      await submitTransactionAsync(alice, tx);
 
-            let worker = cluster.fork({
-                WORKER_NAME,
-                STAGES: id + 2
-            });
-            worker.on('message', msg => {
-                for (let key in msg) {
-                    increaseCounter(key, msg[key]);
-                }
-            });
-            waiting.push(new Promise(res => worker.on('exit', res)));
+      const worker = cluster.fork({
+        WORKER_NAME,
+        STAGES: id + 2,
+      });
+      worker.on('message', msg => {
+        for (const key in msg) {
+          increaseCounter(key, msg[key]);
         }
-        await Promise.all(waiting);
-        testDone = true;
-    })
+      });
+      waiting.push(new Promise(res => worker.on('exit', res)));
+    }
+    await Promise.all(waiting);
+    testDone = true;
+  });
 } else {
-    increaseCounter('startedWorkers', 1);
-    usingApi(async (api) => {
-        await distributeBalance(privateKey(process.env.WORKER_NAME as string), api, 400n * 10n ** 22n, 10);
-    });
-    const interval = setInterval(() => {
-        flushCounterToMaster();
-    }, 100);
-    interval.unref();
+  increaseCounter('startedWorkers', 1);
+  usingApi(async (api) => {
+    await distributeBalance(privateKey(process.env.WORKER_NAME as string), api, 400n * 10n ** 22n, 10);
+  });
+  const interval = setInterval(() => {
+    flushCounterToMaster();
+  }, 100);
+  interval.unref();
 }
\ No newline at end of file

--- a/tests/src/transfer.test.ts
+++ b/tests/src/transfer.test.ts
@@ -64,7 +64,7 @@
   });
 
   it('User can transfer owned token', async () => {
-    await usingApi(async (api) => {
+    await usingApi(async () => {
       const Alice = privateKey('//Alice');
       const Bob = privateKey('//Bob');
       // nft
@@ -77,17 +77,23 @@
       await transferExpectSuccess(fungibleCollectionId, newFungibleTokenId, Alice, Bob, 1, 'Fungible');
       // reFungible
       const reFungibleCollectionId = await
-        createCollectionExpectSuccess({mode: {type: 'ReFungible'}});
+      createCollectionExpectSuccess({mode: {type: 'ReFungible'}});
       const newReFungibleTokenId = await createItemExpectSuccess(Alice, reFungibleCollectionId, 'ReFungible');
-      await transferExpectSuccess(reFungibleCollectionId,
-        newReFungibleTokenId, Alice, Bob, 100, 'ReFungible');
+      await transferExpectSuccess(
+        reFungibleCollectionId,
+        newReFungibleTokenId,
+        Alice,
+        Bob,
+        100,
+        'ReFungible',
+      );
     });
   });
 });
 
 describe('Negative Integration Test Transfer(recipient, collection_id, item_id, value)', () => {
   before(async () => {
-    await usingApi(async (api: ApiPromise) => {
+    await usingApi(async () => {
       Alice = privateKey('//Alice');
       Bob = privateKey('//Bob');
       Charlie = privateKey('//Charlie');
@@ -119,11 +125,17 @@
     await transferExpectFail(fungibleCollectionId, newFungibleTokenId, Alice, Bob, 1, 'Fungible');
     // reFungible
     const reFungibleCollectionId = await
-      createCollectionExpectSuccess({mode: {type: 'ReFungible'}});
+    createCollectionExpectSuccess({mode: {type: 'ReFungible'}});
     const newReFungibleTokenId = await createItemExpectSuccess(Alice, reFungibleCollectionId, 'ReFungible');
     await destroyCollectionExpectSuccess(reFungibleCollectionId);
-    await transferExpectFail(reFungibleCollectionId,
-      newReFungibleTokenId, Alice, Bob, 1, 'ReFungible');
+    await transferExpectFail(
+      reFungibleCollectionId,
+      newReFungibleTokenId,
+      Alice,
+      Bob,
+      1,
+      'ReFungible',
+    );
   });
   it('Transfer with not existed item_id', async () => {
     // nft
@@ -134,9 +146,15 @@
     await transferExpectFail(fungibleCollectionId, 2, Alice, Bob, 1, 'Fungible');
     // reFungible
     const reFungibleCollectionId = await
-      createCollectionExpectSuccess({mode: {type: 'ReFungible'}});
-    await transferExpectFail(reFungibleCollectionId,
-      2, Alice, Bob, 1, 'ReFungible');
+    createCollectionExpectSuccess({mode: {type: 'ReFungible'}});
+    await transferExpectFail(
+      reFungibleCollectionId,
+      2,
+      Alice,
+      Bob,
+      1,
+      'ReFungible',
+    );
   });
   it('Transfer with deleted item_id', async () => {
     // nft
@@ -151,11 +169,17 @@
     await transferExpectFail(fungibleCollectionId, newFungibleTokenId, Alice, Bob, 1, 'Fungible');
     // reFungible
     const reFungibleCollectionId = await
-      createCollectionExpectSuccess({mode: {type: 'ReFungible'}});
+    createCollectionExpectSuccess({mode: {type: 'ReFungible'}});
     const newReFungibleTokenId = await createItemExpectSuccess(Alice, reFungibleCollectionId, 'ReFungible');
     await burnItemExpectSuccess(Alice, reFungibleCollectionId, newReFungibleTokenId, 1);
-    await transferExpectFail(reFungibleCollectionId,
-      newReFungibleTokenId, Alice, Bob, 1, 'ReFungible');
+    await transferExpectFail(
+      reFungibleCollectionId,
+      newReFungibleTokenId,
+      Alice,
+      Bob,
+      1,
+      'ReFungible',
+    );
   });
   it('Transfer with recipient that is not owner', async () => {
     // nft
@@ -168,9 +192,15 @@
     await transferExpectFail(fungibleCollectionId, newFungibleTokenId, Charlie, Bob, 1, 'Fungible');
     // reFungible
     const reFungibleCollectionId = await
-      createCollectionExpectSuccess({mode: {type: 'ReFungible'}});
+    createCollectionExpectSuccess({mode: {type: 'ReFungible'}});
     const newReFungibleTokenId = await createItemExpectSuccess(Alice, reFungibleCollectionId, 'ReFungible');
-    await transferExpectFail(reFungibleCollectionId,
-      newReFungibleTokenId, Charlie, Bob, 1, 'ReFungible');
+    await transferExpectFail(
+      reFungibleCollectionId,
+      newReFungibleTokenId,
+      Charlie,
+      Bob,
+      1,
+      'ReFungible',
+    );
   });
 });

--- a/tests/src/transferFrom.test.ts
+++ b/tests/src/transferFrom.test.ts
@@ -14,7 +14,6 @@
   createCollectionExpectSuccess,
   createFungibleItemExpectSuccess,
   createItemExpectSuccess,
-  destroyCollectionExpectSuccess,
   getAllowance,
   transferFromExpectFail,
   transferFromExpectSuccess,
@@ -31,7 +30,7 @@
   let Charlie: IKeyringPair;
 
   before(async () => {
-    await usingApi(async (api) => {
+    await usingApi(async () => {
       Alice = privateKey('//Alice');
       Bob = privateKey('//Bob');
       Charlie = privateKey('//Charlie');
@@ -39,7 +38,7 @@
   });
 
   it('Execute the extrinsic and check nftItemList - owner of token', async () => {
-    await usingApi(async (api: ApiPromise) => {
+    await usingApi(async () => {
       // nft
       const nftCollectionId = await createCollectionExpectSuccess();
       const newNftTokenId = await createItemExpectSuccess(Alice, nftCollectionId, 'NFT');
@@ -52,13 +51,21 @@
       const newFungibleTokenId = await createItemExpectSuccess(Alice, fungibleCollectionId, 'Fungible');
       await approveExpectSuccess(fungibleCollectionId, newFungibleTokenId, Alice, Bob);
       await transferFromExpectSuccess(fungibleCollectionId, newFungibleTokenId, Bob, Alice, Charlie, 1, 'Fungible');
+
       // reFungible
       const reFungibleCollectionId = await
-        createCollectionExpectSuccess({mode: {type: 'ReFungible'}});
+      createCollectionExpectSuccess({mode: {type: 'ReFungible'}});
       const newReFungibleTokenId = await createItemExpectSuccess(Alice, reFungibleCollectionId, 'ReFungible');
       await approveExpectSuccess(reFungibleCollectionId, newReFungibleTokenId, Alice, Bob, 100);
-      await transferFromExpectSuccess(reFungibleCollectionId,
-        newReFungibleTokenId, Bob, Alice, Charlie, 100, 'ReFungible');
+      await transferFromExpectSuccess(
+        reFungibleCollectionId,
+        newReFungibleTokenId,
+        Bob,
+        Alice,
+        Charlie,
+        100,
+        'ReFungible',
+      );
     });
   });
 
@@ -92,7 +99,7 @@
   let Charlie: IKeyringPair;
 
   before(async () => {
-    await usingApi(async (api) => {
+    await usingApi(async () => {
       Alice = privateKey('//Alice');
       Bob = privateKey('//Bob');
       Charlie = privateKey('//Charlie');
@@ -139,7 +146,7 @@
   }); */
 
   it('transferFrom for not approved address', async () => {
-    await usingApi(async (api: ApiPromise) => {
+    await usingApi(async () => {
       // nft
       const nftCollectionId = await createCollectionExpectSuccess();
       const newNftTokenId = await createItemExpectSuccess(Alice, nftCollectionId, 'NFT');
@@ -152,15 +159,21 @@
       await transferFromExpectFail(fungibleCollectionId, newFungibleTokenId, Bob, Alice, Charlie, 1);
       // reFungible
       const reFungibleCollectionId = await
-        createCollectionExpectSuccess({mode: {type: 'ReFungible'}});
+      createCollectionExpectSuccess({mode: {type: 'ReFungible'}});
       const newReFungibleTokenId = await createItemExpectSuccess(Alice, reFungibleCollectionId, 'ReFungible');
-      await transferFromExpectFail(reFungibleCollectionId,
-        newReFungibleTokenId, Bob, Alice, Charlie, 1);
+      await transferFromExpectFail(
+        reFungibleCollectionId,
+        newReFungibleTokenId,
+        Bob,
+        Alice,
+        Charlie,
+        1,
+      );
     });
   });
 
   it('transferFrom incorrect token count', async () => {
-    await usingApi(async (api: ApiPromise) => {
+    await usingApi(async () => {
       // nft
       const nftCollectionId = await createCollectionExpectSuccess();
       const newNftTokenId = await createItemExpectSuccess(Alice, nftCollectionId, 'NFT');
@@ -175,16 +188,22 @@
       await transferFromExpectFail(fungibleCollectionId, newFungibleTokenId, Bob, Alice, Charlie, 2);
       // reFungible
       const reFungibleCollectionId = await
-        createCollectionExpectSuccess({mode: {type: 'ReFungible'}});
+      createCollectionExpectSuccess({mode: {type: 'ReFungible'}});
       const newReFungibleTokenId = await createItemExpectSuccess(Alice, reFungibleCollectionId, 'ReFungible');
       await approveExpectSuccess(reFungibleCollectionId, newReFungibleTokenId, Alice, Bob);
-      await transferFromExpectFail(reFungibleCollectionId,
-        newReFungibleTokenId, Bob, Alice, Charlie, 2);
+      await transferFromExpectFail(
+        reFungibleCollectionId,
+        newReFungibleTokenId,
+        Bob,
+        Alice,
+        Charlie,
+        2,
+      );
     });
   });
 
   it('execute transferFrom from account that is not owner of collection', async () => {
-    await usingApi(async (api: ApiPromise) => {
+    await usingApi(async () => {
       const Dave = privateKey('//Dave');
       // nft
       const nftCollectionId = await createCollectionExpectSuccess();
@@ -211,7 +230,7 @@
       }
       // reFungible
       const reFungibleCollectionId = await
-        createCollectionExpectSuccess({mode: {type: 'ReFungible'}});
+      createCollectionExpectSuccess({mode: {type: 'ReFungible'}});
       const newReFungibleTokenId = await createItemExpectSuccess(Alice, reFungibleCollectionId, 'ReFungible');
       try {
         await approveExpectFail(reFungibleCollectionId, newReFungibleTokenId, Dave, Bob);
@@ -223,7 +242,7 @@
     });
   });
   it( 'transferFrom burnt token before approve NFT', async () => {
-    await usingApi(async (api: ApiPromise) => {
+    await usingApi(async () => {
       // nft
       const nftCollectionId = await createCollectionExpectSuccess();
       const newNftTokenId = await createItemExpectSuccess(Alice, nftCollectionId, 'NFT');
@@ -233,7 +252,7 @@
     });
   });
   it( 'transferFrom burnt token before approve Fungible', async () => {
-    await usingApi(async (api: ApiPromise) => {
+    await usingApi(async () => {
       const fungibleCollectionId = await createCollectionExpectSuccess({mode: {type: 'Fungible', decimalPoints: 0}});
       const newFungibleTokenId = await createItemExpectSuccess(Alice, fungibleCollectionId, 'Fungible');
       await burnItemExpectSuccess(Alice, fungibleCollectionId, 1, 10);
@@ -243,7 +262,7 @@
     });
   }); 
   it( 'transferFrom burnt token before approve ReFungible', async () => {
-    await usingApi(async (api: ApiPromise) => {
+    await usingApi(async () => {
       const reFungibleCollectionId = await createCollectionExpectSuccess({mode: {type: 'ReFungible'}});
       const newReFungibleTokenId = await createItemExpectSuccess(Alice, reFungibleCollectionId, 'ReFungible');
       await burnItemExpectSuccess(Alice, reFungibleCollectionId, newReFungibleTokenId, 1);
@@ -254,7 +273,7 @@
   });
   
   it( 'transferFrom burnt token after approve NFT', async () => {
-    await usingApi(async (api: ApiPromise) => {
+    await usingApi(async () => {
       // nft
       const nftCollectionId = await createCollectionExpectSuccess();
       const newNftTokenId = await createItemExpectSuccess(Alice, nftCollectionId, 'NFT');
@@ -264,7 +283,7 @@
     });
   });
   it( 'transferFrom burnt token after approve Fungible', async () => {
-    await usingApi(async (api: ApiPromise) => {
+    await usingApi(async () => {
       const fungibleCollectionId = await createCollectionExpectSuccess({mode: {type: 'Fungible', decimalPoints: 0}});
       const newFungibleTokenId = await createItemExpectSuccess(Alice, fungibleCollectionId, 'Fungible');
       await approveExpectSuccess(fungibleCollectionId, newFungibleTokenId, Alice, Bob);
@@ -274,7 +293,7 @@
     });
   }); 
   it( 'transferFrom burnt token after approve ReFungible', async () => {
-    await usingApi(async (api: ApiPromise) => {
+    await usingApi(async () => {
       const reFungibleCollectionId = await createCollectionExpectSuccess({mode: {type: 'ReFungible'}});
       const newReFungibleTokenId = await createItemExpectSuccess(Alice, reFungibleCollectionId, 'ReFungible');
       await approveExpectSuccess(reFungibleCollectionId, newReFungibleTokenId, Alice, Bob);

--- a/tests/src/util/contracthelpers.ts
+++ b/tests/src/util/contracthelpers.ts
@@ -3,13 +3,13 @@
 // file 'LICENSE', which is part of this source code package.
 //
 
-import chai from "chai";
+import chai from 'chai';
 import chaiAsPromised from 'chai-as-promised';
-import { submitTransactionAsync, submitTransactionExpectFailAsync } from "../substrate/substrate-api";
-import fs from "fs";
-import { Abi, BlueprintPromise as Blueprint, CodePromise, ContractPromise as Contract } from "@polkadot/api-contract";
-import { IKeyringPair } from "@polkadot/types/types";
-import { ApiPromise, Keyring } from "@polkadot/api";
+import { submitTransactionAsync, submitTransactionExpectFailAsync } from '../substrate/substrate-api';
+import fs from 'fs';
+import { Abi, CodePromise, ContractPromise as Contract } from '@polkadot/api-contract';
+import { IKeyringPair } from '@polkadot/types/types';
+import { ApiPromise, Keyring } from '@polkadot/api';
 
 chai.use(chaiAsPromised);
 const expect = chai.expect;
@@ -20,8 +20,9 @@
 const gasLimit = '200000000000';
 const endowment = '100000000000000000';
 
-function deployContract(alice: IKeyringPair, code: CodePromise, constructor: string = 'default', ...args: any[]): Promise<Contract> {
-  return new Promise<Contract>(async (resolve, reject) => {
+/* eslint no-async-promise-executor: "off" */
+function deployContract(alice: IKeyringPair, code: CodePromise, constructor = 'default', ...args: any[]): Promise<Contract> {
+  return new Promise<Contract>(async (resolve) => {
     const unsub = await (code as any)
       .tx[constructor]({value: endowment, gasLimit}, ...args)
       .signAndSend(alice, (result: any) => {
@@ -30,7 +31,7 @@
           resolve((result as any).contract);
           unsub();
         }
-      })
+      });
   });
 }
 
@@ -40,7 +41,7 @@
 
   // Transfer balance to it
   const keyring = new Keyring({ type: 'sr25519' });
-  const alice = keyring.addFromUri(`//Alice`);
+  const alice = keyring.addFromUri('//Alice');
   let amount = new BigNumber(endowment);
   amount = amount.plus(100e15);
   const tx = api.tx.balances.transfer(deployer.address, amount.toFixed());
@@ -71,7 +72,7 @@
   const result = await contract.query.get(deployer.address, value, gasLimit);
 
   if(!result.result.isOk) {
-    throw `Failed to get flipper value`;
+    throw 'Failed to get flipper value';
   }
   return (result.result.asOk.data[0] == 0x00) ? false : true;
 }
@@ -87,19 +88,6 @@
 export async function toggleFlipValueExpectFailure(sender: IKeyringPair, contract: Contract) {
   const tx = contract.tx.flip(value, gasLimit);
   await expect(submitTransactionExpectFailAsync(sender, tx)).to.be.rejected;
-}
-
-function instantiateTransferContract(alice: IKeyringPair, blueprint: Blueprint) : Promise<any> {
-  return new Promise<any>(async (resolve, reject) => {
-    const unsub = await blueprint.tx
-    .default(endowment, gasLimit)
-    .signAndSend(alice, (result) => {
-      if (result.status.isInBlock || result.status.isFinalized) {
-        unsub();
-        resolve(result);
-      }
-    });    
-  });
 }
 
 export async function deployTransferContract(api: ApiPromise): Promise<[Contract, IKeyringPair]> {

--- a/tests/src/util/helpers.ts
+++ b/tests/src/util/helpers.ts
@@ -4,22 +4,18 @@
 //
 
 import { ApiPromise, Keyring } from '@polkadot/api';
-import { Enum, Struct } from '@polkadot/types/codec';
-import type { AccountId, BlockNumber, Call, EventRecord } from '@polkadot/types/interfaces';
-import { u128 } from '@polkadot/types/primitive';
+import type { AccountId, EventRecord } from '@polkadot/types/interfaces';
 import { IKeyringPair } from '@polkadot/types/types';
 import { evmToAddress } from '@polkadot/util-crypto';
 import { BigNumber } from 'bignumber.js';
 import BN from 'bn.js';
 import chai from 'chai';
 import chaiAsPromised from 'chai-as-promised';
-import { alicesPublicKey, nullPublicKey } from '../accounts';
+import { alicesPublicKey } from '../accounts';
 import privateKey from '../substrate/privateKey';
 import { default as usingApi, submitTransactionAsync, submitTransactionExpectFailAsync } from '../substrate/substrate-api';
 import { ICollectionInterface } from '../types';
 import { hexToStr, strToUTF16, utf16ToStr } from './util';
-import { Compact, Option, Raw, Vec } from '@polkadot/types/codec';
-// import { AccountId, AccountIdOf, AccountIndex, Address, AssetId, Balance, BalanceOf, Block, BlockNumber, Call, ChangesTrieConfiguration, Consensus, ConsensusEngineId, Digest, DigestItem, DispatchClass, DispatchInfo, DispatchInfoTo190, EcdsaSignature, Ed25519Signature, Extrinsic, ExtrinsicEra, ExtrinsicPayload, ExtrinsicPayloadUnknown, ExtrinsicPayloadV1, ExtrinsicPayloadV2, ExtrinsicPayloadV3, ExtrinsicPayloadV4, ExtrinsicSignatureV1, ExtrinsicSignatureV2, ExtrinsicSignatureV3, ExtrinsicSignatureV4, ExtrinsicUnknown, ExtrinsicV1, ExtrinsicV2, ExtrinsicV3, ExtrinsicV4, Hash, Header, ImmortalEra, Index, Justification, KeyTypeId, KeyValue, LockIdentifier, LookupSource, LookupTarget, Moment, MortalEra, MultiSignature, Origin, Perbill, Percent, Permill, Perquintill, Phantom, PhantomData, PreRuntime, Seal, SealV0, Signature, SignedBlock, SignerPayload, Sr25519Signature, ValidatorId, Weight, WeightMultiplier } from '@polkadot/types/interfaces/runtime';
 
 chai.use(chaiAsPromised);
 const expect = chai.expect;
@@ -85,10 +81,6 @@
   Owner: number[];
   ConstData: number[];
   VariableData: number[];
-}
-
-interface IFungibleTokenDataType {
-  Value: BN;
 }
 
 interface IGetMessage {
@@ -104,9 +96,9 @@
 }
 
 export function nftEventMessage(events: EventRecord[]): IGetMessage {
-  let checkMsgNftMethod: string = '';
-  let checkMsgTrsMethod: string = '';
-  let checkMsgSysMethod: string = '';
+  let checkMsgNftMethod = '';
+  let checkMsgTrsMethod = '';
+  let checkMsgSysMethod = '';
   events.forEach(({ event: { method, section } }) => {
     if (section === 'nft') {
       checkMsgNftMethod = method;
@@ -128,7 +120,7 @@
   const result: GenericResult = {
     success: false,
   };
-  events.forEach(({ phase, event: { data, method, section } }) => {
+  events.forEach(({ event: { method } }) => {
     // console.log(`    ${phase}: ${section}.${method}:: ${data}`);
     if (method === 'ExtrinsicSuccess') {
       result.success = true;
@@ -141,8 +133,8 @@
 
 export function getCreateCollectionResult(events: EventRecord[]): CreateCollectionResult {
   let success = false;
-  let collectionId: number = 0;
-  events.forEach(({ phase, event: { data, method, section } }) => {
+  let collectionId = 0;
+  events.forEach(({ event: { data, method, section } }) => {
     // console.log(`    ${phase}: ${section}.${method}:: ${data}`);
     if (method == 'ExtrinsicSuccess') {
       success = true;
@@ -159,10 +151,10 @@
 
 export function getCreateItemResult(events: EventRecord[]): CreateItemResult {
   let success = false;
-  let collectionId: number = 0;
-  let itemId: number = 0;
+  let collectionId = 0;
+  let itemId = 0;
   let recipient;
-  events.forEach(({ phase, event: { data, method, section } }) => {
+  events.forEach(({ event: { data, method, section } }) => {
     // console.log(`    ${phase}: ${section}.${method}:: ${data}`);
     if (method == 'ExtrinsicSuccess') {
       success = true;
@@ -235,12 +227,12 @@
   mode: { type: 'NFT' },
   name: 'name',
   tokenPrefix: 'prefix',
-}
+};
 
 export async function createCollectionExpectSuccess(params: Partial<CreateCollectionParams> = {}): Promise<number> {
   const { name, description, mode, tokenPrefix } = { ...defaultCreateCollectionParams, ...params };
 
-  let collectionId: number = 0;
+  let collectionId = 0;
   await usingApi(async (api) => {
     // Get number of collections before the transaction
     const AcollectionCount = parseInt((await api.query.nft.createdCollectionCount()).toString(), 10);
@@ -351,9 +343,8 @@
 }
 
 function getDestroyResult(events: EventRecord[]): boolean {
-  let success: boolean = false;
-  events.forEach(({ phase, event: { data, method, section } }) => {
-    // console.log(`    ${phase}: ${section}.${method}:: ${data}`);
+  let success = false;
+  events.forEach(({ event: { method } }) => {
     if (method == 'ExtrinsicSuccess') {
       success = true;
     }
@@ -361,7 +352,7 @@
   return success;
 }
 
-export async function destroyCollectionExpectFailure(collectionId: number, senderSeed: string = '//Alice') {
+export async function destroyCollectionExpectFailure(collectionId: number, senderSeed = '//Alice') {
   await usingApi(async (api) => {
     // Run the DestroyCollection transaction
     const alicePrivateKey = privateKey(senderSeed);
@@ -370,7 +361,7 @@
   });
 }
 
-export async function destroyCollectionExpectSuccess(collectionId: number, senderSeed: string = '//Alice') {
+export async function destroyCollectionExpectSuccess(collectionId: number, senderSeed = '//Alice') {
   await usingApi(async (api) => {
     // Run the DestroyCollection transaction
     const alicePrivateKey = privateKey(senderSeed);
@@ -465,7 +456,7 @@
   });
 }
 
-export async function setCollectionSponsorExpectFailure(collectionId: number, sponsor: string, senderSeed: string = '//Alice') {
+export async function setCollectionSponsorExpectFailure(collectionId: number, sponsor: string, senderSeed = '//Alice') {
   await usingApi(async (api) => {
 
     // Run the transaction
@@ -475,7 +466,7 @@
   });
 }
 
-export async function confirmSponsorshipExpectSuccess(collectionId: number, senderSeed: string = '//Alice') {
+export async function confirmSponsorshipExpectSuccess(collectionId: number, senderSeed = '//Alice') {
   await usingApi(async (api) => {
 
     // Run the transaction
@@ -496,7 +487,7 @@
 }
 
 
-export async function confirmSponsorshipExpectFailure(collectionId: number, senderSeed: string = '//Alice') {
+export async function confirmSponsorshipExpectFailure(collectionId: number, senderSeed = '//Alice') {
   await usingApi(async (api) => {
 
     // Run the transaction
@@ -546,7 +537,7 @@
   });
 }
 
-export async function toggleContractWhitelistExpectSuccess(sender: IKeyringPair, contractAddress: AccountId | string, enabled: boolean) {
+export async function toggleContractWhitelistExpectSuccess(sender: IKeyringPair, contractAddress: AccountId | string) {
   await usingApi(async (api) => {
     const tx = api.tx.nft.toggleContractWhiteList(contractAddress, true);
     const events = await submitTransactionAsync(sender, tx);
@@ -557,7 +548,7 @@
 }
 
 export async function isWhitelistedInContract(contractAddress: AccountId | string, user: string) {
-  let whitelisted: boolean = false;
+  let whitelisted = false;
   await usingApi(async (api) => {
     whitelisted = (await api.query.nft.contractWhiteList(contractAddress, user)).toJSON() as boolean;
   });
@@ -659,8 +650,10 @@
 }
 
 export async function
-  approveExpectSuccess(collectionId: number,
-    tokenId: number, owner: IKeyringPair, approved: IKeyringPair | CrossAccountId | string, amount: number | bigint = 1) {
+approveExpectSuccess(
+  collectionId: number,
+  tokenId: number, owner: IKeyringPair, approved: IKeyringPair | CrossAccountId | string, amount: number | bigint = 1,
+) {
   await usingApi(async (api: ApiPromise) => {
     approved = normalizeAccountId(approved);
     const allowanceBefore =
@@ -677,21 +670,22 @@
 }
 
 export async function
-  transferFromExpectSuccess(collectionId: number,
-    tokenId: number,
-    accountApproved: IKeyringPair,
-    accountFrom: IKeyringPair | CrossAccountId,
-    accountTo: IKeyringPair | CrossAccountId,
-    value: number | bigint = 1,
-    type: string = 'NFT') {
+transferFromExpectSuccess(
+  collectionId: number,
+  tokenId: number,
+  accountApproved: IKeyringPair,
+  accountFrom: IKeyringPair | CrossAccountId,
+  accountTo: IKeyringPair | CrossAccountId,
+  value: number | bigint = 1,
+  type = 'NFT',
+) {
   await usingApi(async (api: ApiPromise) => {
     const to = normalizeAccountId(accountTo);
     let balanceBefore = new BN(0);
     if (type === 'Fungible') {
       balanceBefore = await api.query.nft.balance(collectionId, toSubstrateAddress(to)) as unknown as BN;
     }
-    const transferFromTx = api.tx.nft.transferFrom(
-      normalizeAccountId(accountFrom), to, collectionId, tokenId, value);
+    const transferFromTx = api.tx.nft.transferFrom(normalizeAccountId(accountFrom), to, collectionId, tokenId, value);
     const events = await submitTransactionAsync(accountApproved, transferFromTx);
     const result = getCreateItemResult(events);
     // tslint:disable-next-line:no-unused-expression
@@ -714,15 +708,16 @@
 }
 
 export async function
-  transferFromExpectFail(collectionId: number,
-    tokenId: number,
-    accountApproved: IKeyringPair,
-    accountFrom: IKeyringPair,
-    accountTo: IKeyringPair,
-    value: number | bigint = 1) {
+transferFromExpectFail(
+  collectionId: number,
+  tokenId: number,
+  accountApproved: IKeyringPair,
+  accountFrom: IKeyringPair,
+  accountTo: IKeyringPair,
+  value: number | bigint = 1,
+) {
   await usingApi(async (api: ApiPromise) => {
-    const transferFromTx = api.tx.nft.transferFrom(
-      normalizeAccountId(accountFrom.address), normalizeAccountId(accountTo.address), collectionId, tokenId, value);
+    const transferFromTx = api.tx.nft.transferFrom(normalizeAccountId(accountFrom.address), normalizeAccountId(accountTo.address), collectionId, tokenId, value);
     const events = await expect(submitTransactionExpectFailAsync(accountApproved, transferFromTx)).to.be.rejected;
     const result = getCreateCollectionResult(events);
     // tslint:disable-next-line:no-unused-expression
@@ -730,36 +725,34 @@
   });
 }
 
+/* eslint no-async-promise-executor: "off" */
 async function getBlockNumber(api: ApiPromise): Promise<number> {
-  return new Promise<number>(async (resolve, reject) => {
+  return new Promise<number>(async (resolve) => {
     const unsubscribe = await api.rpc.chain.subscribeNewHeads((head) => {
-        unsubscribe();
-        resolve(head.number.toNumber());
+      unsubscribe();
+      resolve(head.number.toNumber());
     });
   });
 }
 
 export async function
-scheduleTransferExpectSuccess(collectionId: number,
-                      tokenId: number,
-                      sender: IKeyringPair,
-                      recipient: IKeyringPair,
-                      value: number | bigint = 1,
-                      type: string = 'NFT') {
+scheduleTransferExpectSuccess(
+  collectionId: number,
+  tokenId: number,
+  sender: IKeyringPair,
+  recipient: IKeyringPair,
+  value: number | bigint = 1,
+) {
   await usingApi(async (api: ApiPromise) => {
-    let balanceBefore = new BN(0);
-
-
-    let blockNumber: number | undefined = await getBlockNumber(api);
-    let expectedBlockNumber = blockNumber + 2;
+    const blockNumber: number | undefined = await getBlockNumber(api);
+    const expectedBlockNumber = blockNumber + 2;
 
     expect(blockNumber).to.be.greaterThan(0);
     const transferTx = await api.tx.nft.transfer(recipient.address, collectionId, tokenId, value); 
     const scheduleTx = await api.tx.scheduler.schedule(expectedBlockNumber, null, 0, transferTx);
 
-    const events = await submitTransactionAsync(sender, scheduleTx);
+    await submitTransactionAsync(sender, scheduleTx);
 
-    const sponsorBalanceBefore = new BigNumber((await api.query.system.account(sender.address)).data.free.toString());
     const recipientBalanceBefore = new BigNumber((await api.query.system.account(recipient.address)).data.free.toString());
 
     const nftItemDataBefore = (await api.query.nft.nftItemList(collectionId, tokenId)).toJSON() as unknown as ITokenDataType;
@@ -768,7 +761,6 @@
     // sleep for 2 blocks
     await new Promise(resolve => setTimeout(resolve, 6000 * 2));
 
-    const sponsorBalanceAfter = new BigNumber((await api.query.system.account(sender.address)).data.free.toString());
     const recipientBalanceAfter = new BigNumber((await api.query.system.account(recipient.address)).data.free.toString());
 
     const nftItemData = (await api.query.nft.nftItemList(collectionId, tokenId)).toJSON() as unknown as ITokenDataType;
@@ -779,12 +771,14 @@
 
 
 export async function
-  transferExpectSuccess(collectionId: number,
-    tokenId: number,
-    sender: IKeyringPair,
-    recipient: IKeyringPair | CrossAccountId,
-    value: number | bigint = 1,
-    type: string = 'NFT') {
+transferExpectSuccess(
+  collectionId: number,
+  tokenId: number,
+  sender: IKeyringPair,
+  recipient: IKeyringPair | CrossAccountId,
+  value: number | bigint = 1,
+  type = 'NFT',
+) {
   await usingApi(async (api: ApiPromise) => {
     const to = normalizeAccountId(recipient);
 
@@ -820,12 +814,13 @@
 }
 
 export async function
-  transferExpectFail(collectionId: number,
-    tokenId: number,
-    sender: IKeyringPair,
-    recipient: IKeyringPair,
-    value: number | bigint = 1,
-    type: string = 'NFT') {
+transferExpectFail(
+  collectionId: number,
+  tokenId: number,
+  sender: IKeyringPair,
+  recipient: IKeyringPair,
+  value: number | bigint = 1,
+) {
   await usingApi(async (api: ApiPromise) => {
     const transferTx = api.tx.nft.transfer(normalizeAccountId(recipient.address), collectionId, tokenId, value);
     const events = await expect(submitTransactionExpectFailAsync(sender, transferTx)).to.be.rejected;
@@ -838,8 +833,10 @@
 }
 
 export async function
-  approveExpectFail(collectionId: number,
-    tokenId: number, owner: IKeyringPair, approved: IKeyringPair, amount: number | bigint = 1) {
+approveExpectFail(
+  collectionId: number,
+  tokenId: number, owner: IKeyringPair, approved: IKeyringPair, amount: number | bigint = 1,
+) {
   await usingApi(async (api: ApiPromise) => {
     const approveNftTx = api.tx.nft.approve(normalizeAccountId(approved.address), collectionId, tokenId, amount);
     const events = await expect(submitTransactionExpectFailAsync(owner, approveNftTx)).to.be.rejected;
@@ -876,9 +873,8 @@
   });
 }
 
-export async function createItemExpectSuccess(
-  sender: IKeyringPair, collectionId: number, createMode: string, owner: CrossAccountId | string = sender.address) {
-  let newItemId: number = 0;
+export async function createItemExpectSuccess(sender: IKeyringPair, collectionId: number, createMode: string, owner: CrossAccountId | string = sender.address) {
+  let newItemId = 0;
   await usingApi(async (api) => {
     const to = normalizeAccountId(owner);
     const AItemCount = parseInt((await api.query.nft.itemListIndex(collectionId)).toString(), 10);
@@ -919,8 +915,7 @@
   return newItemId;
 }
 
-export async function createItemExpectFailure(
-  sender: IKeyringPair, collectionId: number, createMode: string, owner: string = sender.address) {
+export async function createItemExpectFailure(sender: IKeyringPair, collectionId: number, createMode: string, owner: string = sender.address) {
   await usingApi(async (api) => {
     const tx = api.tx.nft.createItem(collectionId, normalizeAccountId(owner), createMode);
     
@@ -994,7 +989,7 @@
 }
 
 export async function isWhitelisted(collectionId: number, address: string) {
-  let whitelisted: boolean = false;
+  let whitelisted = false;
   await usingApi(async (api) => {
     whitelisted = (await api.query.nft.whiteList(collectionId, address)).toJSON() as unknown as boolean;
   });

--- a/tests/src/util/util.ts
+++ b/tests/src/util/util.ts
@@ -4,7 +4,7 @@
 //
 
 export function strToUTF16(str: string): any {
-  let buf: number[] = [];
+  const buf: number[] = [];
   for (let i=0, strLen=str.length; i < strLen; i++) {
     buf.push(str.charCodeAt(i));
   }
@@ -12,7 +12,7 @@
 }
 
 export function utf16ToStr(buf: number[]): string {
-  let str: string = "";
+  let str = '';
   for (let i=0, strLen=buf.length; i < strLen; i++) {
     if (buf[i] != 0) str += String.fromCharCode(buf[i]);
     else break;
@@ -21,13 +21,13 @@
 }
 
 export function hexToStr(buf: string): string {
-  let str: string = "";
-  let hexStart = buf.indexOf("0x");
+  let str = '';
+  let hexStart = buf.indexOf('0x');
   if (hexStart < 0) hexStart = 0;
   else hexStart = 2;  
   for (let i=hexStart, strLen=buf.length; i < strLen; i+=2) {
-    let ch = buf[i] + buf[i+1];
-    let num = parseInt(ch, 16);
+    const ch = buf[i] + buf[i+1];
+    const num = parseInt(ch, 16);
     if (num != 0) str += String.fromCharCode(num);
     else break;
   }