rename Impl contracts to Mock

contracts/mocks/AddressImpl.sol

@@ -2,7 +2,7 @@ pragma solidity ^0.6.0;
 
 import "../utils/Address.sol";
 
-contract AddressImpl {
+contract AddressMock {
     function isContract(address account) external view returns (bool) {
         return Address.isContract(account);
     }

contracts/mocks/ArraysImpl.sol

@@ -2,7 +2,7 @@ pragma solidity ^0.6.0;
 
 import "../utils/Arrays.sol";
 
-contract ArraysImpl {
+contract ArraysMock {
     using Arrays for uint256[];
 
     uint256[] private _array;

contracts/mocks/CountersImpl.sol

@@ -2,7 +2,7 @@ pragma solidity ^0.6.0;
 
 import "../utils/Counters.sol";
 
-contract CountersImpl {
+contract CountersMock {
     using Counters for Counters.Counter;
 
     Counters.Counter private _counter;

contracts/mocks/Create2Impl.sol

@@ -3,7 +3,7 @@ pragma solidity ^0.6.0;
 import "../utils/Create2.sol";
 import "../introspection/ERC1820Implementer.sol";
 
-contract Create2Impl {
+contract Create2Mock {
     function deploy(uint256 value, bytes32 salt, bytes memory code) public {
         Create2.deploy(value, salt, code);
     }

test/utils/Address.test.js

@@ -3,14 +3,14 @@ const { accounts, contract } = require('@openzeppelin/test-environment');
 const { balance, ether, expectRevert, send } = require('@openzeppelin/test-helpers');
 const { expect } = require('chai');
 
-const AddressImpl = contract.fromArtifact('AddressImpl');
+const AddressMock = contract.fromArtifact('AddressMock');
 const EtherReceiver = contract.fromArtifact('EtherReceiverMock');
 
 describe('Address', function () {
   const [ recipient, other ] = accounts;
 
   beforeEach(async function () {
-    this.mock = await AddressImpl.new();
+    this.mock = await AddressMock.new();
   });
 
   describe('isContract', function () {
@@ -19,7 +19,7 @@ describe('Address', function () {
     });
 
     it('should return true for contract address', async function () {
-      const contract = await AddressImpl.new();
+      const contract = await AddressMock.new();
       expect(await this.mock.isContract(contract.address)).to.equal(true);
     });
   });

test/utils/Arrays.test.js

@@ -3,14 +3,14 @@ require('@openzeppelin/test-helpers');
 
 const { expect } = require('chai');
 
-const ArraysImpl = contract.fromArtifact('ArraysImpl');
+const ArraysMock = contract.fromArtifact('ArraysMock');
 
 describe('Arrays', function () {
   context('Even number of elements', function () {
     const EVEN_ELEMENTS_ARRAY = [11, 12, 13, 14, 15, 16, 17, 18, 19, 20];
 
     beforeEach(async function () {
-      this.arrays = await ArraysImpl.new(EVEN_ELEMENTS_ARRAY);
+      this.arrays = await ArraysMock.new(EVEN_ELEMENTS_ARRAY);
     });
 
     it('should return correct index for the basic case', async function () {
@@ -38,7 +38,7 @@ describe('Arrays', function () {
     const ODD_ELEMENTS_ARRAY = [11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21];
 
     beforeEach(async function () {
-      this.arrays = await ArraysImpl.new(ODD_ELEMENTS_ARRAY);
+      this.arrays = await ArraysMock.new(ODD_ELEMENTS_ARRAY);
     });
 
     it('should return correct index for the basic case', async function () {
@@ -66,7 +66,7 @@ describe('Arrays', function () {
     const WITH_GAP_ARRAY = [11, 12, 13, 14, 15, 20, 21, 22, 23, 24];
 
     beforeEach(async function () {
-      this.arrays = await ArraysImpl.new(WITH_GAP_ARRAY);
+      this.arrays = await ArraysMock.new(WITH_GAP_ARRAY);
     });
 
     it('should return index of first element in next filled range', async function () {
@@ -76,7 +76,7 @@ describe('Arrays', function () {
 
   context('Empty array', function () {
     beforeEach(async function () {
-      this.arrays = await ArraysImpl.new([]);
+      this.arrays = await ArraysMock.new([]);
     });
 
     it('should always return 0 for empty array', async function () {

test/utils/Counters.test.js

@@ -3,11 +3,11 @@ const { expectRevert } = require('@openzeppelin/test-helpers');
 
 const { expect } = require('chai');
 
-const CountersImpl = contract.fromArtifact('CountersImpl');
+const CountersMock = contract.fromArtifact('CountersMock');
 
 describe('Counters', function () {
   beforeEach(async function () {
-    this.counter = await CountersImpl.new();
+    this.counter = await CountersMock.new();
   });
 
   it('starts at zero', async function () {

test/utils/Create2.test.js

@@ -3,7 +3,7 @@ const { balance, BN, ether, expectRevert, send } = require('@openzeppelin/test-h
 
 const { expect } = require('chai');
 
-const Create2Impl = contract.fromArtifact('Create2Impl');
+const Create2Mock = contract.fromArtifact('Create2Mock');
 const ERC20Mock = contract.fromArtifact('ERC20Mock');
 const ERC1820Implementer = contract.fromArtifact('ERC1820Implementer');
 
@@ -21,7 +21,7 @@ describe('Create2', function () {
   const constructorByteCode = `${ERC20Mock.bytecode}${encodedParams}`;
 
   beforeEach(async function () {
-    this.factory = await Create2Impl.new();
+    this.factory = await Create2Mock.new();
   });
 
   it('should compute the correct contract address', async function () {