this is used in tests

test/examples/SimpleToken.test.js

@@ -8,34 +8,32 @@ require('chai')
   .should();
 
 contract('SimpleToken', function ([_, creator]) {
-  let token;
-
   const ZERO_ADDRESS = '0x0000000000000000000000000000000000000000';
 
   beforeEach(async function () {
-    token = await SimpleToken.new({ from: creator });
+    this.token = await SimpleToken.new({ from: creator });
   });
 
   it('has a name', async function () {
-    (await token.name()).should.equal('SimpleToken');
+    (await this.token.name()).should.equal('SimpleToken');
   });
 
   it('has a symbol', async function () {
-    (await token.symbol()).should.equal('SIM');
+    (await this.token.symbol()).should.equal('SIM');
   });
 
   it('has 18 decimals', async function () {
-    (await token.decimals()).should.be.bignumber.equal(18);
+    (await this.token.decimals()).should.be.bignumber.equal(18);
   });
 
   it('assigns the initial total supply to the creator', async function () {
-    const totalSupply = await token.totalSupply();
-    const creatorBalance = await token.balanceOf(creator);
+    const totalSupply = await this.token.totalSupply();
+    const creatorBalance = await this.token.balanceOf(creator);
 
     creatorBalance.should.be.bignumber.equal(totalSupply);
 
-    const receipt = await web3.eth.getTransactionReceipt(token.transactionHash);
-    const logs = decodeLogs(receipt.logs, SimpleToken, token.address);
+    const receipt = await web3.eth.getTransactionReceipt(this.token.transactionHash);
+    const logs = decodeLogs(receipt.logs, SimpleToken, this.token.address);
     logs.length.should.equal(1);
     logs[0].event.should.equal('Transfer');
     logs[0].args.from.valueOf().should.equal(ZERO_ADDRESS);

test/library/MerkleProof.test.js

@@ -7,10 +7,8 @@ require('chai')
   .should();
 
 contract('MerkleProof', function () {
-  let merkleProof;
-
   beforeEach(async function () {
-    merkleProof = await MerkleProofWrapper.new();
+    this.merkleProof = await MerkleProofWrapper.new();
   });
 
   describe('verify', function () {
@@ -24,7 +22,7 @@ contract('MerkleProof', function () {
 
       const leaf = bufferToHex(sha3(elements[0]));
 
-      (await merkleProof.verify(proof, root, leaf)).should.equal(true);
+      (await this.merkleProof.verify(proof, root, leaf)).should.equal(true);
     });
 
     it('should return false for an invalid Merkle proof', async function () {
@@ -40,7 +38,7 @@ contract('MerkleProof', function () {
 
       const badProof = badMerkleTree.getHexProof(badElements[0]);
 
-      (await merkleProof.verify(badProof, correctRoot, correctLeaf)).should.equal(false);
+      (await this.merkleProof.verify(badProof, correctRoot, correctLeaf)).should.equal(false);
     });
 
     it('should return false for a Merkle proof of invalid length', async function () {
@@ -54,7 +52,7 @@ contract('MerkleProof', function () {
 
       const leaf = bufferToHex(sha3(elements[0]));
 
-      (await merkleProof.verify(badProof, root, leaf)).should.equal(false);
+      (await this.merkleProof.verify(badProof, root, leaf)).should.equal(false);
     });
   });
 });

test/token/ERC20/ERC20Detailed.test.js

@@ -7,25 +7,23 @@ require('chai')
 const ERC20DetailedMock = artifacts.require('ERC20DetailedMock');
 
 contract('ERC20Detailed', function () {
-  let detailedERC20 = null;
-
   const _name = 'My Detailed ERC20';
   const _symbol = 'MDT';
   const _decimals = 18;
 
   beforeEach(async function () {
-    detailedERC20 = await ERC20DetailedMock.new(_name, _symbol, _decimals);
+    this.detailedERC20 = await ERC20DetailedMock.new(_name, _symbol, _decimals);
   });
 
   it('has a name', async function () {
-    (await detailedERC20.name()).should.be.equal(_name);
+    (await this.detailedERC20.name()).should.be.equal(_name);
   });
 
   it('has a symbol', async function () {
-    (await detailedERC20.symbol()).should.be.equal(_symbol);
+    (await this.detailedERC20.symbol()).should.be.equal(_symbol);
   });
 
   it('has an amount of decimals', async function () {
-    (await detailedERC20.decimals()).should.be.bignumber.equal(_decimals);
+    (await this.detailedERC20.decimals()).should.be.bignumber.equal(_decimals);
   });
 });

test/utils/ReentrancyGuard.test.js

@@ -9,28 +9,25 @@ require('chai')
   .should();
 
 contract('ReentrancyGuard', function () {
-  let reentrancyMock;
-
   beforeEach(async function () {
-    reentrancyMock = await ReentrancyMock.new();
-    const initialCounter = await reentrancyMock.counter();
-    initialCounter.should.be.bignumber.equal(0);
+    this.reentrancyMock = await ReentrancyMock.new();
+    (await this.reentrancyMock.counter()).should.be.bignumber.equal(0);
   });
 
   it('should not allow remote callback', async function () {
     const attacker = await ReentrancyAttack.new();
-    await expectThrow(reentrancyMock.countAndCall(attacker.address));
+    await expectThrow(this.reentrancyMock.countAndCall(attacker.address));
   });
 
   // The following are more side-effects than intended behavior:
   // I put them here as documentation, and to monitor any changes
   // in the side-effects.
 
   it('should not allow local recursion', async function () {
-    await expectThrow(reentrancyMock.countLocalRecursive(10));
+    await expectThrow(this.reentrancyMock.countLocalRecursive(10));
   });
 
   it('should not allow indirect local recursion', async function () {
-    await expectThrow(reentrancyMock.countThisRecursive(10));
+    await expectThrow(this.reentrancyMock.countThisRecursive(10));
   });
 });