Migrate ERC721 tests (#4793)

Co-authored-by: ernestognw <ernestognw@gmail.com>

test/token/ERC721/ERC721.test.js

@@ -1,15 +1,23 @@
+const { ethers } = require('hardhat');
+const { loadFixture } = require('@nomicfoundation/hardhat-network-helpers');
+
 const { shouldBehaveLikeERC721, shouldBehaveLikeERC721Metadata } = require('./ERC721.behavior');
 
-const ERC721 = artifacts.require('$ERC721');
+const name = 'Non Fungible Token';
+const symbol = 'NFT';
 
-contract('ERC721', function (accounts) {
-  const name = 'Non Fungible Token';
-  const symbol = 'NFT';
+async function fixture() {
+  return {
+    accounts: await ethers.getSigners(),
+    token: await ethers.deployContract('$ERC721', [name, symbol]),
+  };
+}
 
+describe('ERC721', function () {
   beforeEach(async function () {
-    this.token = await ERC721.new(name, symbol);
+    Object.assign(this, await loadFixture(fixture));
   });
 
-  shouldBehaveLikeERC721(...accounts);
-  shouldBehaveLikeERC721Metadata(name, symbol, ...accounts);
+  shouldBehaveLikeERC721();
+  shouldBehaveLikeERC721Metadata(name, symbol);
 });

test/token/ERC721/ERC721Enumerable.test.js

@@ -1,20 +1,28 @@
+const { ethers } = require('hardhat');
+const { loadFixture } = require('@nomicfoundation/hardhat-network-helpers');
+
 const {
   shouldBehaveLikeERC721,
   shouldBehaveLikeERC721Metadata,
   shouldBehaveLikeERC721Enumerable,
 } = require('./ERC721.behavior');
 
-const ERC721Enumerable = artifacts.require('$ERC721Enumerable');
+const name = 'Non Fungible Token';
+const symbol = 'NFT';
 
-contract('ERC721Enumerable', function (accounts) {
-  const name = 'Non Fungible Token';
-  const symbol = 'NFT';
+async function fixture() {
+  return {
+    accounts: await ethers.getSigners(),
+    token: await ethers.deployContract('$ERC721Enumerable', [name, symbol]),
+  };
+}
 
+describe('ERC721', function () {
   beforeEach(async function () {
-    this.token = await ERC721Enumerable.new(name, symbol);
+    Object.assign(this, await loadFixture(fixture));
   });
 
-  shouldBehaveLikeERC721(...accounts);
-  shouldBehaveLikeERC721Metadata(name, symbol, ...accounts);
-  shouldBehaveLikeERC721Enumerable(...accounts);
+  shouldBehaveLikeERC721();
+  shouldBehaveLikeERC721Metadata(name, symbol);
+  shouldBehaveLikeERC721Enumerable();
 });

test/token/ERC721/extensions/ERC721Burnable.test.js

@@ -1,80 +1,75 @@
-const { BN, constants, expectEvent } = require('@openzeppelin/test-helpers');
-
+const { ethers } = require('hardhat');
 const { expect } = require('chai');
-const { expectRevertCustomError } = require('../../../helpers/customError');
-
-const ERC721Burnable = artifacts.require('$ERC721Burnable');
-
-contract('ERC721Burnable', function (accounts) {
-  const [owner, approved, another] = accounts;
+const { loadFixture } = require('@nomicfoundation/hardhat-network-helpers');
 
-  const firstTokenId = new BN(1);
-  const secondTokenId = new BN(2);
-  const unknownTokenId = new BN(3);
+const name = 'Non Fungible Token';
+const symbol = 'NFT';
+const tokenId = 1n;
+const otherTokenId = 2n;
+const unknownTokenId = 3n;
 
-  const name = 'Non Fungible Token';
-  const symbol = 'NFT';
+async function fixture() {
+  const [owner, approved, another] = await ethers.getSigners();
+  const token = await ethers.deployContract('$ERC721Burnable', [name, symbol]);
+  return { owner, approved, another, token };
+}
 
+describe('ERC721Burnable', function () {
   beforeEach(async function () {
-    this.token = await ERC721Burnable.new(name, symbol);
+    Object.assign(this, await loadFixture(fixture));
   });
 
   describe('like a burnable ERC721', function () {
     beforeEach(async function () {
-      await this.token.$_mint(owner, firstTokenId);
-      await this.token.$_mint(owner, secondTokenId);
+      await this.token.$_mint(this.owner, tokenId);
+      await this.token.$_mint(this.owner, otherTokenId);
     });
 
     describe('burn', function () {
-      const tokenId = firstTokenId;
-      let receipt = null;
-
       describe('when successful', function () {
-        beforeEach(async function () {
-          receipt = await this.token.burn(tokenId, { from: owner });
-        });
+        it('emits a burn event, burns the given token ID and adjusts the balance of the owner', async function () {
+          const balanceBefore = await this.token.balanceOf(this.owner);
 
-        it('burns the given token ID and adjusts the balance of the owner', async function () {
-          await expectRevertCustomError(this.token.ownerOf(tokenId), 'ERC721NonexistentToken', [tokenId]);
-          expect(await this.token.balanceOf(owner)).to.be.bignumber.equal('1');
-        });
+          await expect(this.token.connect(this.owner).burn(tokenId))
+            .to.emit(this.token, 'Transfer')
+            .withArgs(this.owner.address, ethers.ZeroAddress, tokenId);
 
-        it('emits a burn event', async function () {
-          expectEvent(receipt, 'Transfer', {
-            from: owner,
-            to: constants.ZERO_ADDRESS,
-            tokenId: tokenId,
-          });
+          await expect(this.token.ownerOf(tokenId))
+            .to.be.revertedWithCustomError(this.token, 'ERC721NonexistentToken')
+            .withArgs(tokenId);
+
+          expect(await this.token.balanceOf(this.owner)).to.equal(balanceBefore - 1n);
         });
       });
 
       describe('when there is a previous approval burned', function () {
         beforeEach(async function () {
-          await this.token.approve(approved, tokenId, { from: owner });
-          receipt = await this.token.burn(tokenId, { from: owner });
+          await this.token.connect(this.owner).approve(this.approved, tokenId);
+          await this.token.connect(this.owner).burn(tokenId);
         });
 
         context('getApproved', function () {
           it('reverts', async function () {
-            await expectRevertCustomError(this.token.getApproved(tokenId), 'ERC721NonexistentToken', [tokenId]);
+            await expect(this.token.getApproved(tokenId))
+              .to.be.revertedWithCustomError(this.token, 'ERC721NonexistentToken')
+              .withArgs(tokenId);
           });
         });
       });
 
       describe('when there is no previous approval burned', function () {
         it('reverts', async function () {
-          await expectRevertCustomError(this.token.burn(tokenId, { from: another }), 'ERC721InsufficientApproval', [
-            another,
-            tokenId,
-          ]);
+          await expect(this.token.connect(this.another).burn(tokenId))
+            .to.be.revertedWithCustomError(this.token, 'ERC721InsufficientApproval')
+            .withArgs(this.another.address, tokenId);
         });
       });
 
       describe('when the given token ID was not tracked by this contract', function () {
         it('reverts', async function () {
-          await expectRevertCustomError(this.token.burn(unknownTokenId, { from: owner }), 'ERC721NonexistentToken', [
-            unknownTokenId,
-          ]);
+          await expect(this.token.connect(this.owner).burn(unknownTokenId))
+            .to.be.revertedWithCustomError(this.token, 'ERC721NonexistentToken')
+            .withArgs(unknownTokenId);
         });
       });
     });

test/token/ERC721/extensions/ERC721Consecutive.test.js

@@ -1,55 +1,60 @@
-const { constants, expectEvent } = require('@openzeppelin/test-helpers');
+const { ethers } = require('hardhat');
 const { expect } = require('chai');
+const { loadFixture } = require('@nomicfoundation/hardhat-network-helpers');
+
 const { sum } = require('../../../helpers/math');
-const { expectRevertCustomError } = require('../../../helpers/customError');
-const { ZERO_ADDRESS } = require('@openzeppelin/test-helpers/src/constants');
-
-const ERC721ConsecutiveMock = artifacts.require('$ERC721ConsecutiveMock');
-const ERC721ConsecutiveEnumerableMock = artifacts.require('$ERC721ConsecutiveEnumerableMock');
-const ERC721ConsecutiveNoConstructorMintMock = artifacts.require('$ERC721ConsecutiveNoConstructorMintMock');
-
-contract('ERC721Consecutive', function (accounts) {
-  const [user1, user2, user3, receiver] = accounts;
-
-  const name = 'Non Fungible Token';
-  const symbol = 'NFT';
-  const batches = [
-    { receiver: user1, amount: 0 },
-    { receiver: user1, amount: 1 },
-    { receiver: user1, amount: 2 },
-    { receiver: user2, amount: 5 },
-    { receiver: user3, amount: 0 },
-    { receiver: user1, amount: 7 },
-  ];
-  const delegates = [user1, user3];
-
-  for (const offset of [0, 1, 42]) {
+
+const name = 'Non Fungible Token';
+const symbol = 'NFT';
+
+describe('ERC721Consecutive', function () {
+  for (const offset of [0n, 1n, 42n]) {
     describe(`with offset ${offset}`, function () {
-      beforeEach(async function () {
-        this.token = await ERC721ConsecutiveMock.new(
+      async function fixture() {
+        const accounts = await ethers.getSigners();
+        const [alice, bruce, chris, receiver] = accounts;
+
+        const batches = [
+          { receiver: alice, amount: 0n },
+          { receiver: alice, amount: 1n },
+          { receiver: alice, amount: 2n },
+          { receiver: bruce, amount: 5n },
+          { receiver: chris, amount: 0n },
+          { receiver: alice, amount: 7n },
+        ];
+        const delegates = [alice, chris];
+
+        const token = await ethers.deployContract('$ERC721ConsecutiveMock', [
           name,
           symbol,
           offset,
           delegates,
           batches.map(({ receiver }) => receiver),
           batches.map(({ amount }) => amount),
-        );
+        ]);
+
+        return { accounts, alice, bruce, chris, receiver, batches, delegates, token };
+      }
+
+      beforeEach(async function () {
+        Object.assign(this, await loadFixture(fixture));
       });
 
       describe('minting during construction', function () {
         it('events are emitted at construction', async function () {
           let first = offset;
-
-          for (const batch of batches) {
+          for (const batch of this.batches) {
             if (batch.amount > 0) {
-              await expectEvent.inConstruction(this.token, 'ConsecutiveTransfer', {
-                fromTokenId: web3.utils.toBN(first),
-                toTokenId: web3.utils.toBN(first + batch.amount - 1),
-                fromAddress: constants.ZERO_ADDRESS,
-                toAddress: batch.receiver,
-              });
+              await expect(this.token.deploymentTransaction())
+                .to.emit(this.token, 'ConsecutiveTransfer')
+                .withArgs(
+                  first /* fromTokenId */,
+                  first + batch.amount - 1n /* toTokenId */,
+                  ethers.ZeroAddress /* fromAddress */,
+                  batch.receiver.address /* toAddress */,
+                );
             } else {
-              // expectEvent.notEmitted.inConstruction only looks at event name, and doesn't check the parameters
+              // ".to.not.emit" only looks at event name, and doesn't check the parameters
             }
             first += batch.amount;
           }
@@ -57,166 +62,175 @@ contract('ERC721Consecutive', function (accounts) {
 
         it('ownership is set', async function () {
           const owners = [
-            ...Array(offset).fill(constants.ZERO_ADDRESS),
-            ...batches.flatMap(({ receiver, amount }) => Array(amount).fill(receiver)),
+            ...Array(Number(offset)).fill(ethers.ZeroAddress),
+            ...this.batches.flatMap(({ receiver, amount }) => Array(Number(amount)).fill(receiver.address)),
           ];
 
           for (const tokenId in owners) {
-            if (owners[tokenId] != constants.ZERO_ADDRESS) {
-              expect(await this.token.ownerOf(tokenId)).to.be.equal(owners[tokenId]);
+            if (owners[tokenId] != ethers.ZeroAddress) {
+              expect(await this.token.ownerOf(tokenId)).to.equal(owners[tokenId]);
             }
           }
         });
 
         it('balance & voting power are set', async function () {
-          for (const account of accounts) {
+          for (const account of this.accounts) {
             const balance =
-              sum(...batches.filter(({ receiver }) => receiver === account).map(({ amount }) => amount)) ?? 0;
+              sum(...this.batches.filter(({ receiver }) => receiver === account).map(({ amount }) => amount)) ?? 0n;
 
-            expect(await this.token.balanceOf(account)).to.be.bignumber.equal(web3.utils.toBN(balance));
+            expect(await this.token.balanceOf(account)).to.equal(balance);
 
             // If not delegated at construction, check before + do delegation
-            if (!delegates.includes(account)) {
-              expect(await this.token.getVotes(account)).to.be.bignumber.equal(web3.utils.toBN(0));
+            if (!this.delegates.includes(account)) {
+              expect(await this.token.getVotes(account)).to.equal(0n);
 
-              await this.token.delegate(account, { from: account });
+              await this.token.connect(account).delegate(account);
             }
 
             // At this point all accounts should have delegated
-            expect(await this.token.getVotes(account)).to.be.bignumber.equal(web3.utils.toBN(balance));
+            expect(await this.token.getVotes(account)).to.equal(balance);
           }
         });
 
         it('reverts on consecutive minting to the zero address', async function () {
-          await expectRevertCustomError(
-            ERC721ConsecutiveMock.new(name, symbol, offset, delegates, [ZERO_ADDRESS], [10]),
-            'ERC721InvalidReceiver',
-            [ZERO_ADDRESS],
-          );
+          await expect(
+            ethers.deployContract('$ERC721ConsecutiveMock', [
+              name,
+              symbol,
+              offset,
+              this.delegates,
+              [ethers.ZeroAddress],
+              [10],
+            ]),
+          )
+            .to.be.revertedWithCustomError(this.token, 'ERC721InvalidReceiver')
+            .withArgs(ethers.ZeroAddress);
         });
       });
 
       describe('minting after construction', function () {
         it('consecutive minting is not possible after construction', async function () {
-          await expectRevertCustomError(this.token.$_mintConsecutive(user1, 10), 'ERC721ForbiddenBatchMint', []);
+          await expect(this.token.$_mintConsecutive(this.alice, 10)).to.be.revertedWithCustomError(
+            this.token,
+            'ERC721ForbiddenBatchMint',
+          );
         });
 
         it('simple minting is possible after construction', async function () {
-          const tokenId = sum(...batches.map(b => b.amount)) + offset;
+          const tokenId = sum(...this.batches.map(b => b.amount)) + offset;
 
-          await expectRevertCustomError(this.token.ownerOf(tokenId), 'ERC721NonexistentToken', [tokenId]);
+          await expect(this.token.ownerOf(tokenId))
+            .to.be.revertedWithCustomError(this.token, 'ERC721NonexistentToken')
+            .withArgs(tokenId);
 
-          expectEvent(await this.token.$_mint(user1, tokenId), 'Transfer', {
-            from: constants.ZERO_ADDRESS,
-            to: user1,
-            tokenId: tokenId.toString(),
-          });
+          await expect(this.token.$_mint(this.alice, tokenId))
+            .to.emit(this.token, 'Transfer')
+            .withArgs(ethers.ZeroAddress, this.alice.address, tokenId);
         });
 
         it('cannot mint a token that has been batched minted', async function () {
-          const tokenId = sum(...batches.map(b => b.amount)) + offset - 1;
+          const tokenId = sum(...this.batches.map(b => b.amount)) + offset - 1n;
 
-          expect(await this.token.ownerOf(tokenId)).to.be.not.equal(constants.ZERO_ADDRESS);
+          expect(await this.token.ownerOf(tokenId)).to.not.equal(ethers.ZeroAddress);
 
-          await expectRevertCustomError(this.token.$_mint(user1, tokenId), 'ERC721InvalidSender', [ZERO_ADDRESS]);
+          await expect(this.token.$_mint(this.alice, tokenId))
+            .to.be.revertedWithCustomError(this.token, 'ERC721InvalidSender')
+            .withArgs(ethers.ZeroAddress);
         });
       });
 
       describe('ERC721 behavior', function () {
-        const tokenId = web3.utils.toBN(offset + 1);
+        const tokenId = offset + 1n;
 
         it('core takes over ownership on transfer', async function () {
-          await this.token.transferFrom(user1, receiver, tokenId, { from: user1 });
+          await this.token.connect(this.alice).transferFrom(this.alice, this.receiver, tokenId);
 
-          expect(await this.token.ownerOf(tokenId)).to.be.equal(receiver);
+          expect(await this.token.ownerOf(tokenId)).to.equal(this.receiver.address);
         });
 
         it('tokens can be burned and re-minted #1', async function () {
-          expectEvent(await this.token.$_burn(tokenId, { from: user1 }), 'Transfer', {
-            from: user1,
-            to: constants.ZERO_ADDRESS,
-            tokenId,
-          });
+          await expect(this.token.connect(this.alice).$_burn(tokenId))
+            .to.emit(this.token, 'Transfer')
+            .withArgs(this.alice.address, ethers.ZeroAddress, tokenId);
 
-          await expectRevertCustomError(this.token.ownerOf(tokenId), 'ERC721NonexistentToken', [tokenId]);
+          await expect(this.token.ownerOf(tokenId))
+            .to.be.revertedWithCustomError(this.token, 'ERC721NonexistentToken')
+            .withArgs(tokenId);
 
-          expectEvent(await this.token.$_mint(user2, tokenId), 'Transfer', {
-            from: constants.ZERO_ADDRESS,
-            to: user2,
-            tokenId,
-          });
+          await expect(this.token.$_mint(this.bruce, tokenId))
+            .to.emit(this.token, 'Transfer')
+            .withArgs(ethers.ZeroAddress, this.bruce.address, tokenId);
 
-          expect(await this.token.ownerOf(tokenId)).to.be.equal(user2);
+          expect(await this.token.ownerOf(tokenId)).to.equal(this.bruce.address);
         });
 
         it('tokens can be burned and re-minted #2', async function () {
-          const tokenId = web3.utils.toBN(sum(...batches.map(({ amount }) => amount)) + offset);
+          const tokenId = sum(...this.batches.map(({ amount }) => amount)) + offset;
 
-          await expectRevertCustomError(this.token.ownerOf(tokenId), 'ERC721NonexistentToken', [tokenId]);
+          await expect(this.token.ownerOf(tokenId))
+            .to.be.revertedWithCustomError(this.token, 'ERC721NonexistentToken')
+            .withArgs(tokenId);
 
           // mint
-          await this.token.$_mint(user1, tokenId);
+          await expect(this.token.$_mint(this.alice, tokenId))
+            .to.emit(this.token, 'Transfer')
+            .withArgs(ethers.ZeroAddress, this.alice.address, tokenId);
 
-          expect(await this.token.ownerOf(tokenId), user1);
+          expect(await this.token.ownerOf(tokenId)).to.equal(this.alice.address);
 
           // burn
-          expectEvent(await this.token.$_burn(tokenId, { from: user1 }), 'Transfer', {
-            from: user1,
-            to: constants.ZERO_ADDRESS,
-            tokenId,
-          });
+          await expect(await this.token.$_burn(tokenId))
+            .to.emit(this.token, 'Transfer')
+            .withArgs(this.alice.address, ethers.ZeroAddress, tokenId);
 
-          await expectRevertCustomError(this.token.ownerOf(tokenId), 'ERC721NonexistentToken', [tokenId]);
+          await expect(this.token.ownerOf(tokenId))
+            .to.be.revertedWithCustomError(this.token, 'ERC721NonexistentToken')
+            .withArgs(tokenId);
 
           // re-mint
-          expectEvent(await this.token.$_mint(user2, tokenId), 'Transfer', {
-            from: constants.ZERO_ADDRESS,
-            to: user2,
-            tokenId,
-          });
+          await expect(this.token.$_mint(this.bruce, tokenId))
+            .to.emit(this.token, 'Transfer')
+            .withArgs(ethers.ZeroAddress, this.bruce.address, tokenId);
 
-          expect(await this.token.ownerOf(tokenId), user2);
+          expect(await this.token.ownerOf(tokenId)).to.equal(this.bruce.address);
         });
       });
     });
   }
 
   describe('invalid use', function () {
+    const receiver = ethers.Wallet.createRandom();
+
     it('cannot mint a batch larger than 5000', async function () {
-      await expectRevertCustomError(
-        ERC721ConsecutiveMock.new(name, symbol, 0, [], [user1], ['5001']),
-        'ERC721ExceededMaxBatchMint',
-        [5000, 5001],
-      );
+      const { interface } = await ethers.getContractFactory('$ERC721ConsecutiveMock');
+
+      await expect(ethers.deployContract('$ERC721ConsecutiveMock', [name, symbol, 0, [], [receiver], [5001n]]))
+        .to.be.revertedWithCustomError({ interface }, 'ERC721ExceededMaxBatchMint')
+        .withArgs(5001n, 5000n);
     });
 
     it('cannot use single minting during construction', async function () {
-      await expectRevertCustomError(
-        ERC721ConsecutiveNoConstructorMintMock.new(name, symbol),
-        'ERC721ForbiddenMint',
-        [],
-      );
+      const { interface } = await ethers.getContractFactory('$ERC721ConsecutiveNoConstructorMintMock');
+
+      await expect(
+        ethers.deployContract('$ERC721ConsecutiveNoConstructorMintMock', [name, symbol]),
+      ).to.be.revertedWithCustomError({ interface }, 'ERC721ForbiddenMint');
     });
 
     it('cannot use single minting during construction', async function () {
-      await expectRevertCustomError(
-        ERC721ConsecutiveNoConstructorMintMock.new(name, symbol),
-        'ERC721ForbiddenMint',
-        [],
-      );
+      const { interface } = await ethers.getContractFactory('$ERC721ConsecutiveNoConstructorMintMock');
+
+      await expect(
+        ethers.deployContract('$ERC721ConsecutiveNoConstructorMintMock', [name, symbol]),
+      ).to.be.revertedWithCustomError({ interface }, 'ERC721ForbiddenMint');
     });
 
     it('consecutive mint not compatible with enumerability', async function () {
-      await expectRevertCustomError(
-        ERC721ConsecutiveEnumerableMock.new(
-          name,
-          symbol,
-          batches.map(({ receiver }) => receiver),
-          batches.map(({ amount }) => amount),
-        ),
-        'ERC721EnumerableForbiddenBatchMint',
-        [],
-      );
+      const { interface } = await ethers.getContractFactory('$ERC721ConsecutiveEnumerableMock');
+
+      await expect(
+        ethers.deployContract('$ERC721ConsecutiveEnumerableMock', [name, symbol, [receiver], [100n]]),
+      ).to.be.revertedWithCustomError({ interface }, 'ERC721EnumerableForbiddenBatchMint');
     });
   });
 });

test/token/ERC721/extensions/ERC721Pausable.test.js

@@ -1,89 +1,80 @@
-const { BN, constants } = require('@openzeppelin/test-helpers');
-
+const { ethers } = require('hardhat');
 const { expect } = require('chai');
-const { expectRevertCustomError } = require('../../../helpers/customError');
-
-const ERC721Pausable = artifacts.require('$ERC721Pausable');
+const { loadFixture } = require('@nomicfoundation/hardhat-network-helpers');
 
-contract('ERC721Pausable', function (accounts) {
-  const [owner, receiver, operator] = accounts;
+const name = 'Non Fungible Token';
+const symbol = 'NFT';
+const tokenId = 1n;
+const otherTokenId = 2n;
+const data = ethers.Typed.bytes('0x42');
 
-  const name = 'Non Fungible Token';
-  const symbol = 'NFT';
+async function fixture() {
+  const [owner, receiver, operator] = await ethers.getSigners();
+  const token = await ethers.deployContract('$ERC721Pausable', [name, symbol]);
+  return { owner, receiver, operator, token };
+}
 
+describe('ERC721Pausable', function () {
   beforeEach(async function () {
-    this.token = await ERC721Pausable.new(name, symbol);
+    Object.assign(this, await loadFixture(fixture));
   });
 
   context('when token is paused', function () {
-    const firstTokenId = new BN(1);
-    const secondTokenId = new BN(1337);
-
-    const mockData = '0x42';
-
     beforeEach(async function () {
-      await this.token.$_mint(owner, firstTokenId, { from: owner });
+      await this.token.$_mint(this.owner, tokenId);
       await this.token.$_pause();
     });
 
     it('reverts when trying to transferFrom', async function () {
-      await expectRevertCustomError(
-        this.token.transferFrom(owner, receiver, firstTokenId, { from: owner }),
-        'EnforcedPause',
-        [],
-      );
+      await expect(
+        this.token.connect(this.owner).transferFrom(this.owner, this.receiver, tokenId),
+      ).to.be.revertedWithCustomError(this.token, 'EnforcedPause');
     });
 
     it('reverts when trying to safeTransferFrom', async function () {
-      await expectRevertCustomError(
-        this.token.safeTransferFrom(owner, receiver, firstTokenId, { from: owner }),
-        'EnforcedPause',
-        [],
-      );
+      await expect(
+        this.token.connect(this.owner).safeTransferFrom(this.owner, this.receiver, tokenId),
+      ).to.be.revertedWithCustomError(this.token, 'EnforcedPause');
     });
 
     it('reverts when trying to safeTransferFrom with data', async function () {
-      await expectRevertCustomError(
-        this.token.methods['safeTransferFrom(address,address,uint256,bytes)'](owner, receiver, firstTokenId, mockData, {
-          from: owner,
-        }),
-        'EnforcedPause',
-        [],
-      );
+      await expect(
+        this.token.connect(this.owner).safeTransferFrom(this.owner, this.receiver, tokenId, data),
+      ).to.be.revertedWithCustomError(this.token, 'EnforcedPause');
     });
 
     it('reverts when trying to mint', async function () {
-      await expectRevertCustomError(this.token.$_mint(receiver, secondTokenId), 'EnforcedPause', []);
+      await expect(this.token.$_mint(this.receiver, otherTokenId)).to.be.revertedWithCustomError(
+        this.token,
+        'EnforcedPause',
+      );
     });
 
     it('reverts when trying to burn', async function () {
-      await expectRevertCustomError(this.token.$_burn(firstTokenId), 'EnforcedPause', []);
+      await expect(this.token.$_burn(tokenId)).to.be.revertedWithCustomError(this.token, 'EnforcedPause');
     });
 
     describe('getApproved', function () {
       it('returns approved address', async function () {
-        const approvedAccount = await this.token.getApproved(firstTokenId);
-        expect(approvedAccount).to.equal(constants.ZERO_ADDRESS);
+        expect(await this.token.getApproved(tokenId)).to.equal(ethers.ZeroAddress);
       });
     });
 
     describe('balanceOf', function () {
       it('returns the amount of tokens owned by the given address', async function () {
-        const balance = await this.token.balanceOf(owner);
-        expect(balance).to.be.bignumber.equal('1');
+        expect(await this.token.balanceOf(this.owner)).to.equal(1n);
       });
     });
 
     describe('ownerOf', function () {
       it('returns the amount of tokens owned by the given address', async function () {
-        const ownerOfToken = await this.token.ownerOf(firstTokenId);
-        expect(ownerOfToken).to.equal(owner);
+        expect(await this.token.ownerOf(tokenId)).to.equal(this.owner.address);
       });
     });
 
     describe('isApprovedForAll', function () {
       it('returns the approval of the operator', async function () {
-        expect(await this.token.isApprovedForAll(owner, operator)).to.equal(false);
+        expect(await this.token.isApprovedForAll(this.owner, this.operator)).to.be.false;
       });
     });
   });

test/token/ERC721/extensions/ERC721Royalty.test.js

@@ -1,45 +1,55 @@
-require('@openzeppelin/test-helpers');
+const { ethers } = require('hardhat');
+const { expect } = require('chai');
+const { loadFixture } = require('@nomicfoundation/hardhat-network-helpers');
 
 const { shouldBehaveLikeERC2981 } = require('../../common/ERC2981.behavior');
 
-const ERC721Royalty = artifacts.require('$ERC721Royalty');
+const name = 'Non Fungible Token';
+const symbol = 'NFT';
 
-contract('ERC721Royalty', function (accounts) {
-  const [account1, account2, recipient] = accounts;
-  const tokenId1 = web3.utils.toBN('1');
-  const tokenId2 = web3.utils.toBN('2');
-  const royalty = web3.utils.toBN('200');
-  const salePrice = web3.utils.toBN('1000');
+const tokenId1 = 1n;
+const tokenId2 = 2n;
+const royalty = 200n;
+const salePrice = 1000n;
 
+async function fixture() {
+  const [account1, account2, recipient] = await ethers.getSigners();
+
+  const token = await ethers.deployContract('$ERC721Royalty', [name, symbol]);
+  await token.$_mint(account1, tokenId1);
+  await token.$_mint(account1, tokenId2);
+
+  return { account1, account2, recipient, token };
+}
+
+describe('ERC721Royalty', function () {
   beforeEach(async function () {
-    this.token = await ERC721Royalty.new('My Token', 'TKN');
-
-    await this.token.$_mint(account1, tokenId1);
-    await this.token.$_mint(account1, tokenId2);
-    this.account1 = account1;
-    this.account2 = account2;
-    this.tokenId1 = tokenId1;
-    this.tokenId2 = tokenId2;
-    this.salePrice = salePrice;
+    Object.assign(
+      this,
+      await loadFixture(fixture),
+      { tokenId1, tokenId2, royalty, salePrice }, // set for behavior tests
+    );
   });
 
   describe('token specific functions', function () {
     beforeEach(async function () {
-      await this.token.$_setTokenRoyalty(tokenId1, recipient, royalty);
+      await this.token.$_setTokenRoyalty(tokenId1, this.recipient, royalty);
     });
 
     it('royalty information are kept during burn and re-mint', async function () {
       await this.token.$_burn(tokenId1);
 
-      const tokenInfoA = await this.token.royaltyInfo(tokenId1, salePrice);
-      expect(tokenInfoA[0]).to.be.equal(recipient);
-      expect(tokenInfoA[1]).to.be.bignumber.equal(salePrice.mul(royalty).divn(1e4));
+      expect(await this.token.royaltyInfo(tokenId1, salePrice)).to.deep.equal([
+        this.recipient.address,
+        (salePrice * royalty) / 10000n,
+      ]);
 
-      await this.token.$_mint(account2, tokenId1);
+      await this.token.$_mint(this.account2, tokenId1);
 
-      const tokenInfoB = await this.token.royaltyInfo(tokenId1, salePrice);
-      expect(tokenInfoB[0]).to.be.equal(recipient);
-      expect(tokenInfoB[1]).to.be.bignumber.equal(salePrice.mul(royalty).divn(1e4));
+      expect(await this.token.royaltyInfo(tokenId1, salePrice)).to.deep.equal([
+        this.recipient.address,
+        (salePrice * royalty) / 10000n,
+      ]);
     });
   });
 

test/token/ERC721/extensions/ERC721URIStorage.test.js

@@ -1,63 +1,64 @@
-const { BN, expectEvent } = require('@openzeppelin/test-helpers');
+const { ethers } = require('hardhat');
 const { expect } = require('chai');
+const { loadFixture } = require('@nomicfoundation/hardhat-network-helpers');
 
 const { shouldSupportInterfaces } = require('../../../utils/introspection/SupportsInterface.behavior');
-const { expectRevertCustomError } = require('../../../helpers/customError');
-
-const ERC721URIStorageMock = artifacts.require('$ERC721URIStorageMock');
-
-contract('ERC721URIStorage', function (accounts) {
-  const [owner] = accounts;
-
-  const name = 'Non Fungible Token';
-  const symbol = 'NFT';
-
-  const firstTokenId = new BN('5042');
-  const nonExistentTokenId = new BN('13');
 
+const name = 'Non Fungible Token';
+const symbol = 'NFT';
+const baseURI = 'https://api.example.com/v1/';
+const otherBaseURI = 'https://api.example.com/v2/';
+const sampleUri = 'mock://mytoken';
+const tokenId = 1n;
+const nonExistentTokenId = 2n;
+
+async function fixture() {
+  const [owner] = await ethers.getSigners();
+  const token = await ethers.deployContract('$ERC721URIStorageMock', [name, symbol]);
+  return { owner, token };
+}
+
+contract('ERC721URIStorage', function () {
   beforeEach(async function () {
-    this.token = await ERC721URIStorageMock.new(name, symbol);
+    Object.assign(this, await loadFixture(fixture));
   });
 
   shouldSupportInterfaces(['0x49064906']);
 
   describe('token URI', function () {
     beforeEach(async function () {
-      await this.token.$_mint(owner, firstTokenId);
+      await this.token.$_mint(this.owner, tokenId);
     });
 
-    const baseURI = 'https://api.example.com/v1/';
-    const sampleUri = 'mock://mytoken';
-
     it('it is empty by default', async function () {
-      expect(await this.token.tokenURI(firstTokenId)).to.be.equal('');
+      expect(await this.token.tokenURI(tokenId)).to.equal('');
     });
 
     it('reverts when queried for non existent token id', async function () {
-      await expectRevertCustomError(this.token.tokenURI(nonExistentTokenId), 'ERC721NonexistentToken', [
-        nonExistentTokenId,
-      ]);
+      await expect(this.token.tokenURI(nonExistentTokenId))
+        .to.be.revertedWithCustomError(this.token, 'ERC721NonexistentToken')
+        .withArgs(nonExistentTokenId);
     });
 
     it('can be set for a token id', async function () {
-      await this.token.$_setTokenURI(firstTokenId, sampleUri);
-      expect(await this.token.tokenURI(firstTokenId)).to.be.equal(sampleUri);
+      await this.token.$_setTokenURI(tokenId, sampleUri);
+      expect(await this.token.tokenURI(tokenId)).to.equal(sampleUri);
     });
 
     it('setting the uri emits an event', async function () {
-      expectEvent(await this.token.$_setTokenURI(firstTokenId, sampleUri), 'MetadataUpdate', {
-        _tokenId: firstTokenId,
-      });
+      await expect(this.token.$_setTokenURI(tokenId, sampleUri))
+        .to.emit(this.token, 'MetadataUpdate')
+        .withArgs(tokenId);
     });
 
     it('setting the uri for non existent token id is allowed', async function () {
-      expectEvent(await this.token.$_setTokenURI(nonExistentTokenId, sampleUri), 'MetadataUpdate', {
-        _tokenId: nonExistentTokenId,
-      });
+      await expect(await this.token.$_setTokenURI(nonExistentTokenId, sampleUri))
+        .to.emit(this.token, 'MetadataUpdate')
+        .withArgs(nonExistentTokenId);
 
       // value will be accessible after mint
-      await this.token.$_mint(owner, nonExistentTokenId);
-      expect(await this.token.tokenURI(nonExistentTokenId)).to.be.equal(sampleUri);
+      await this.token.$_mint(this.owner, nonExistentTokenId);
+      expect(await this.token.tokenURI(nonExistentTokenId)).to.equal(sampleUri);
     });
 
     it('base URI can be set', async function () {
@@ -67,48 +68,54 @@ contract('ERC721URIStorage', function (accounts) {
 
     it('base URI is added as a prefix to the token URI', async function () {
       await this.token.setBaseURI(baseURI);
-      await this.token.$_setTokenURI(firstTokenId, sampleUri);
+      await this.token.$_setTokenURI(tokenId, sampleUri);
 
-      expect(await this.token.tokenURI(firstTokenId)).to.be.equal(baseURI + sampleUri);
+      expect(await this.token.tokenURI(tokenId)).to.equal(baseURI + sampleUri);
     });
 
     it('token URI can be changed by changing the base URI', async function () {
       await this.token.setBaseURI(baseURI);
-      await this.token.$_setTokenURI(firstTokenId, sampleUri);
+      await this.token.$_setTokenURI(tokenId, sampleUri);
 
-      const newBaseURI = 'https://api.example.com/v2/';
-      await this.token.setBaseURI(newBaseURI);
-      expect(await this.token.tokenURI(firstTokenId)).to.be.equal(newBaseURI + sampleUri);
+      await this.token.setBaseURI(otherBaseURI);
+      expect(await this.token.tokenURI(tokenId)).to.equal(otherBaseURI + sampleUri);
     });
 
     it('tokenId is appended to base URI for tokens with no URI', async function () {
       await this.token.setBaseURI(baseURI);
 
-      expect(await this.token.tokenURI(firstTokenId)).to.be.equal(baseURI + firstTokenId);
+      expect(await this.token.tokenURI(tokenId)).to.equal(baseURI + tokenId);
     });
 
     it('tokens without URI can be burnt ', async function () {
-      await this.token.$_burn(firstTokenId);
+      await this.token.$_burn(tokenId);
 
-      await expectRevertCustomError(this.token.tokenURI(firstTokenId), 'ERC721NonexistentToken', [firstTokenId]);
+      await expect(this.token.tokenURI(tokenId))
+        .to.be.revertedWithCustomError(this.token, 'ERC721NonexistentToken')
+        .withArgs(tokenId);
     });
 
     it('tokens with URI can be burnt ', async function () {
-      await this.token.$_setTokenURI(firstTokenId, sampleUri);
+      await this.token.$_setTokenURI(tokenId, sampleUri);
 
-      await this.token.$_burn(firstTokenId);
+      await this.token.$_burn(tokenId);
 
-      await expectRevertCustomError(this.token.tokenURI(firstTokenId), 'ERC721NonexistentToken', [firstTokenId]);
+      await expect(this.token.tokenURI(tokenId))
+        .to.be.revertedWithCustomError(this.token, 'ERC721NonexistentToken')
+        .withArgs(tokenId);
     });
 
     it('tokens URI is kept if token is burnt and reminted ', async function () {
-      await this.token.$_setTokenURI(firstTokenId, sampleUri);
+      await this.token.$_setTokenURI(tokenId, sampleUri);
+
+      await this.token.$_burn(tokenId);
 
-      await this.token.$_burn(firstTokenId);
-      await expectRevertCustomError(this.token.tokenURI(firstTokenId), 'ERC721NonexistentToken', [firstTokenId]);
+      await expect(this.token.tokenURI(tokenId))
+        .to.be.revertedWithCustomError(this.token, 'ERC721NonexistentToken')
+        .withArgs(tokenId);
 
-      await this.token.$_mint(owner, firstTokenId);
-      expect(await this.token.tokenURI(firstTokenId)).to.be.equal(sampleUri);
+      await this.token.$_mint(this.owner, tokenId);
+      expect(await this.token.tokenURI(tokenId)).to.equal(sampleUri);
     });
   });
 });

test/token/ERC721/extensions/ERC721Wrapper.test.js

@@ -1,26 +1,29 @@
-const { BN, expectEvent, constants } = require('@openzeppelin/test-helpers');
+const { ethers } = require('hardhat');
 const { expect } = require('chai');
+const { loadFixture } = require('@nomicfoundation/hardhat-network-helpers');
 
 const { shouldBehaveLikeERC721 } = require('../ERC721.behavior');
-const { expectRevertCustomError } = require('../../../helpers/customError');
 
-const ERC721 = artifacts.require('$ERC721');
-const ERC721Wrapper = artifacts.require('$ERC721Wrapper');
+const name = 'Non Fungible Token';
+const symbol = 'NFT';
+const tokenId = 1n;
+const otherTokenId = 2n;
 
-contract('ERC721Wrapper', function (accounts) {
-  const [initialHolder, anotherAccount, approvedAccount] = accounts;
+async function fixture() {
+  const accounts = await ethers.getSigners();
+  const [owner, approved, other] = accounts;
 
-  const name = 'My Token';
-  const symbol = 'MTKN';
-  const firstTokenId = new BN(1);
-  const secondTokenId = new BN(2);
+  const underlying = await ethers.deployContract('$ERC721', [name, symbol]);
+  await underlying.$_safeMint(owner, tokenId);
+  await underlying.$_safeMint(owner, otherTokenId);
+  const token = await ethers.deployContract('$ERC721Wrapper', [`Wrapped ${name}`, `W${symbol}`, underlying]);
 
-  beforeEach(async function () {
-    this.underlying = await ERC721.new(name, symbol);
-    this.token = await ERC721Wrapper.new(`Wrapped ${name}`, `W${symbol}`, this.underlying.address);
+  return { accounts, owner, approved, other, underlying, token };
+}
 
-    await this.underlying.$_safeMint(initialHolder, firstTokenId);
-    await this.underlying.$_safeMint(initialHolder, secondTokenId);
+describe('ERC721Wrapper', function () {
+  beforeEach(async function () {
+    Object.assign(this, await loadFixture(fixture));
   });
 
   it('has a name', async function () {
@@ -32,258 +35,167 @@ contract('ERC721Wrapper', function (accounts) {
   });
 
   it('has underlying', async function () {
-    expect(await this.token.underlying()).to.be.bignumber.equal(this.underlying.address);
+    expect(await this.token.underlying()).to.equal(this.underlying.target);
   });
 
   describe('depositFor', function () {
     it('works with token approval', async function () {
-      await this.underlying.approve(this.token.address, firstTokenId, { from: initialHolder });
-
-      const { tx } = await this.token.depositFor(initialHolder, [firstTokenId], { from: initialHolder });
-
-      await expectEvent.inTransaction(tx, this.underlying, 'Transfer', {
-        from: initialHolder,
-        to: this.token.address,
-        tokenId: firstTokenId,
-      });
-      await expectEvent.inTransaction(tx, this.token, 'Transfer', {
-        from: constants.ZERO_ADDRESS,
-        to: initialHolder,
-        tokenId: firstTokenId,
-      });
+      await this.underlying.connect(this.owner).approve(this.token, tokenId);
+
+      await expect(this.token.connect(this.owner).depositFor(this.owner, [tokenId]))
+        .to.emit(this.underlying, 'Transfer')
+        .withArgs(this.owner.address, this.token.target, tokenId)
+        .to.emit(this.token, 'Transfer')
+        .withArgs(ethers.ZeroAddress, this.owner.address, tokenId);
     });
 
     it('works with approval for all', async function () {
-      await this.underlying.setApprovalForAll(this.token.address, true, { from: initialHolder });
-
-      const { tx } = await this.token.depositFor(initialHolder, [firstTokenId], { from: initialHolder });
-
-      await expectEvent.inTransaction(tx, this.underlying, 'Transfer', {
-        from: initialHolder,
-        to: this.token.address,
-        tokenId: firstTokenId,
-      });
-      await expectEvent.inTransaction(tx, this.token, 'Transfer', {
-        from: constants.ZERO_ADDRESS,
-        to: initialHolder,
-        tokenId: firstTokenId,
-      });
+      await this.underlying.connect(this.owner).setApprovalForAll(this.token, true);
+
+      await expect(this.token.connect(this.owner).depositFor(this.owner, [tokenId]))
+        .to.emit(this.underlying, 'Transfer')
+        .withArgs(this.owner.address, this.token.target, tokenId)
+        .to.emit(this.token, 'Transfer')
+        .withArgs(ethers.ZeroAddress, this.owner.address, tokenId);
     });
 
     it('works sending to another account', async function () {
-      await this.underlying.approve(this.token.address, firstTokenId, { from: initialHolder });
-
-      const { tx } = await this.token.depositFor(anotherAccount, [firstTokenId], { from: initialHolder });
-
-      await expectEvent.inTransaction(tx, this.underlying, 'Transfer', {
-        from: initialHolder,
-        to: this.token.address,
-        tokenId: firstTokenId,
-      });
-      await expectEvent.inTransaction(tx, this.token, 'Transfer', {
-        from: constants.ZERO_ADDRESS,
-        to: anotherAccount,
-        tokenId: firstTokenId,
-      });
+      await this.underlying.connect(this.owner).approve(this.token, tokenId);
+
+      await expect(this.token.connect(this.owner).depositFor(this.other, [tokenId]))
+        .to.emit(this.underlying, 'Transfer')
+        .withArgs(this.owner.address, this.token.target, tokenId)
+        .to.emit(this.token, 'Transfer')
+        .withArgs(ethers.ZeroAddress, this.other.address, tokenId);
     });
 
     it('works with multiple tokens', async function () {
-      await this.underlying.approve(this.token.address, firstTokenId, { from: initialHolder });
-      await this.underlying.approve(this.token.address, secondTokenId, { from: initialHolder });
-
-      const { tx } = await this.token.depositFor(initialHolder, [firstTokenId, secondTokenId], { from: initialHolder });
-
-      await expectEvent.inTransaction(tx, this.underlying, 'Transfer', {
-        from: initialHolder,
-        to: this.token.address,
-        tokenId: firstTokenId,
-      });
-      await expectEvent.inTransaction(tx, this.token, 'Transfer', {
-        from: constants.ZERO_ADDRESS,
-        to: initialHolder,
-        tokenId: firstTokenId,
-      });
-      await expectEvent.inTransaction(tx, this.underlying, 'Transfer', {
-        from: initialHolder,
-        to: this.token.address,
-        tokenId: secondTokenId,
-      });
-      await expectEvent.inTransaction(tx, this.token, 'Transfer', {
-        from: constants.ZERO_ADDRESS,
-        to: initialHolder,
-        tokenId: secondTokenId,
-      });
+      await this.underlying.connect(this.owner).approve(this.token, tokenId);
+      await this.underlying.connect(this.owner).approve(this.token, otherTokenId);
+
+      await expect(this.token.connect(this.owner).depositFor(this.owner, [tokenId, otherTokenId]))
+        .to.emit(this.underlying, 'Transfer')
+        .withArgs(this.owner.address, this.token.target, tokenId)
+        .to.emit(this.token, 'Transfer')
+        .withArgs(ethers.ZeroAddress, this.owner.address, tokenId)
+        .to.emit(this.underlying, 'Transfer')
+        .withArgs(this.owner.address, this.token.target, otherTokenId)
+        .to.emit(this.token, 'Transfer')
+        .withArgs(ethers.ZeroAddress, this.owner.address, otherTokenId);
     });
 
     it('reverts with missing approval', async function () {
-      await expectRevertCustomError(
-        this.token.depositFor(initialHolder, [firstTokenId], { from: initialHolder }),
-        'ERC721InsufficientApproval',
-        [this.token.address, firstTokenId],
-      );
+      await expect(this.token.connect(this.owner).depositFor(this.owner, [tokenId]))
+        .to.be.revertedWithCustomError(this.token, 'ERC721InsufficientApproval')
+        .withArgs(this.token.target, tokenId);
     });
   });
 
   describe('withdrawTo', function () {
     beforeEach(async function () {
-      await this.underlying.approve(this.token.address, firstTokenId, { from: initialHolder });
-      await this.token.depositFor(initialHolder, [firstTokenId], { from: initialHolder });
+      await this.underlying.connect(this.owner).approve(this.token, tokenId);
+      await this.token.connect(this.owner).depositFor(this.owner, [tokenId]);
     });
 
     it('works for an owner', async function () {
-      const { tx } = await this.token.withdrawTo(initialHolder, [firstTokenId], { from: initialHolder });
-
-      await expectEvent.inTransaction(tx, this.underlying, 'Transfer', {
-        from: this.token.address,
-        to: initialHolder,
-        tokenId: firstTokenId,
-      });
-      await expectEvent.inTransaction(tx, this.token, 'Transfer', {
-        from: initialHolder,
-        to: constants.ZERO_ADDRESS,
-        tokenId: firstTokenId,
-      });
+      await expect(this.token.connect(this.owner).withdrawTo(this.owner, [tokenId]))
+        .to.emit(this.underlying, 'Transfer')
+        .withArgs(this.token.target, this.owner.address, tokenId)
+        .to.emit(this.token, 'Transfer')
+        .withArgs(this.owner.address, ethers.ZeroAddress, tokenId);
     });
 
     it('works for an approved', async function () {
-      await this.token.approve(approvedAccount, firstTokenId, { from: initialHolder });
-
-      const { tx } = await this.token.withdrawTo(initialHolder, [firstTokenId], { from: approvedAccount });
-
-      await expectEvent.inTransaction(tx, this.underlying, 'Transfer', {
-        from: this.token.address,
-        to: initialHolder,
-        tokenId: firstTokenId,
-      });
-      await expectEvent.inTransaction(tx, this.token, 'Transfer', {
-        from: initialHolder,
-        to: constants.ZERO_ADDRESS,
-        tokenId: firstTokenId,
-      });
+      await this.token.connect(this.owner).approve(this.approved, tokenId);
+
+      await expect(this.token.connect(this.approved).withdrawTo(this.owner, [tokenId]))
+        .to.emit(this.underlying, 'Transfer')
+        .withArgs(this.token.target, this.owner.address, tokenId)
+        .to.emit(this.token, 'Transfer')
+        .withArgs(this.owner.address, ethers.ZeroAddress, tokenId);
     });
 
     it('works for an approved for all', async function () {
-      await this.token.setApprovalForAll(approvedAccount, true, { from: initialHolder });
-
-      const { tx } = await this.token.withdrawTo(initialHolder, [firstTokenId], { from: approvedAccount });
-
-      await expectEvent.inTransaction(tx, this.underlying, 'Transfer', {
-        from: this.token.address,
-        to: initialHolder,
-        tokenId: firstTokenId,
-      });
-      await expectEvent.inTransaction(tx, this.token, 'Transfer', {
-        from: initialHolder,
-        to: constants.ZERO_ADDRESS,
-        tokenId: firstTokenId,
-      });
+      await this.token.connect(this.owner).setApprovalForAll(this.approved, true);
+
+      await expect(this.token.connect(this.approved).withdrawTo(this.owner, [tokenId]))
+        .to.emit(this.underlying, 'Transfer')
+        .withArgs(this.token.target, this.owner.address, tokenId)
+        .to.emit(this.token, 'Transfer')
+        .withArgs(this.owner.address, ethers.ZeroAddress, tokenId);
     });
 
     it("doesn't work for a non-owner nor approved", async function () {
-      await expectRevertCustomError(
-        this.token.withdrawTo(initialHolder, [firstTokenId], { from: anotherAccount }),
-        'ERC721InsufficientApproval',
-        [anotherAccount, firstTokenId],
-      );
+      await expect(this.token.connect(this.other).withdrawTo(this.owner, [tokenId]))
+        .to.be.revertedWithCustomError(this.token, 'ERC721InsufficientApproval')
+        .withArgs(this.other.address, tokenId);
     });
 
     it('works with multiple tokens', async function () {
-      await this.underlying.approve(this.token.address, secondTokenId, { from: initialHolder });
-      await this.token.depositFor(initialHolder, [secondTokenId], { from: initialHolder });
-
-      const { tx } = await this.token.withdrawTo(initialHolder, [firstTokenId, secondTokenId], { from: initialHolder });
-
-      await expectEvent.inTransaction(tx, this.underlying, 'Transfer', {
-        from: this.token.address,
-        to: initialHolder,
-        tokenId: firstTokenId,
-      });
-      await expectEvent.inTransaction(tx, this.underlying, 'Transfer', {
-        from: this.token.address,
-        to: initialHolder,
-        tokenId: secondTokenId,
-      });
-      await expectEvent.inTransaction(tx, this.token, 'Transfer', {
-        from: initialHolder,
-        to: constants.ZERO_ADDRESS,
-        tokenId: firstTokenId,
-      });
-      await expectEvent.inTransaction(tx, this.token, 'Transfer', {
-        from: initialHolder,
-        to: constants.ZERO_ADDRESS,
-        tokenId: secondTokenId,
-      });
+      await this.underlying.connect(this.owner).approve(this.token, otherTokenId);
+      await this.token.connect(this.owner).depositFor(this.owner, [otherTokenId]);
+
+      await expect(this.token.connect(this.owner).withdrawTo(this.owner, [tokenId, otherTokenId]))
+        .to.emit(this.underlying, 'Transfer')
+        .withArgs(this.token.target, this.owner.address, tokenId)
+        .to.emit(this.underlying, 'Transfer')
+        .withArgs(this.token.target, this.owner.address, tokenId)
+        .to.emit(this.token, 'Transfer')
+        .withArgs(this.owner.address, ethers.ZeroAddress, tokenId)
+        .to.emit(this.token, 'Transfer')
+        .withArgs(this.owner.address, ethers.ZeroAddress, tokenId);
     });
 
     it('works to another account', async function () {
-      const { tx } = await this.token.withdrawTo(anotherAccount, [firstTokenId], { from: initialHolder });
-
-      await expectEvent.inTransaction(tx, this.underlying, 'Transfer', {
-        from: this.token.address,
-        to: anotherAccount,
-        tokenId: firstTokenId,
-      });
-      await expectEvent.inTransaction(tx, this.token, 'Transfer', {
-        from: initialHolder,
-        to: constants.ZERO_ADDRESS,
-        tokenId: firstTokenId,
-      });
+      await expect(this.token.connect(this.owner).withdrawTo(this.other, [tokenId]))
+        .to.emit(this.underlying, 'Transfer')
+        .withArgs(this.token.target, this.other.address, tokenId)
+        .to.emit(this.token, 'Transfer')
+        .withArgs(this.owner.address, ethers.ZeroAddress, tokenId);
     });
   });
 
   describe('onERC721Received', function () {
     it('only allows calls from underlying', async function () {
-      await expectRevertCustomError(
-        this.token.onERC721Received(
-          initialHolder,
-          this.token.address,
-          firstTokenId,
-          anotherAccount, // Correct data
-          { from: anotherAccount },
+      await expect(
+        this.token.connect(this.other).onERC721Received(
+          this.owner,
+          this.token,
+          tokenId,
+          this.other.address, // Correct data
         ),
-        'ERC721UnsupportedToken',
-        [anotherAccount],
-      );
+      )
+        .to.be.revertedWithCustomError(this.token, 'ERC721UnsupportedToken')
+        .withArgs(this.other.address);
     });
 
     it('mints a token to from', async function () {
-      const { tx } = await this.underlying.safeTransferFrom(initialHolder, this.token.address, firstTokenId, {
-        from: initialHolder,
-      });
-
-      await expectEvent.inTransaction(tx, this.token, 'Transfer', {
-        from: constants.ZERO_ADDRESS,
-        to: initialHolder,
-        tokenId: firstTokenId,
-      });
+      await expect(this.underlying.connect(this.owner).safeTransferFrom(this.owner, this.token, tokenId))
+        .to.emit(this.token, 'Transfer')
+        .withArgs(ethers.ZeroAddress, this.owner.address, tokenId);
     });
   });
 
   describe('_recover', function () {
     it('works if there is something to recover', async function () {
       // Should use `transferFrom` to avoid `onERC721Received` minting
-      await this.underlying.transferFrom(initialHolder, this.token.address, firstTokenId, { from: initialHolder });
+      await this.underlying.connect(this.owner).transferFrom(this.owner, this.token, tokenId);
 
-      const { tx } = await this.token.$_recover(anotherAccount, firstTokenId);
-
-      await expectEvent.inTransaction(tx, this.token, 'Transfer', {
-        from: constants.ZERO_ADDRESS,
-        to: anotherAccount,
-        tokenId: firstTokenId,
-      });
+      await expect(this.token.$_recover(this.other, tokenId))
+        .to.emit(this.token, 'Transfer')
+        .withArgs(ethers.ZeroAddress, this.other.address, tokenId);
     });
 
     it('reverts if there is nothing to recover', async function () {
-      const owner = await this.underlying.ownerOf(firstTokenId);
-      await expectRevertCustomError(this.token.$_recover(initialHolder, firstTokenId), 'ERC721IncorrectOwner', [
-        this.token.address,
-        firstTokenId,
-        owner,
-      ]);
+      const holder = await this.underlying.ownerOf(tokenId);
+
+      await expect(this.token.$_recover(holder, tokenId))
+        .to.be.revertedWithCustomError(this.token, 'ERC721IncorrectOwner')
+        .withArgs(this.token.target, tokenId, holder);
     });
   });
 
   describe('ERC712 behavior', function () {
-    shouldBehaveLikeERC721(...accounts);
+    shouldBehaveLikeERC721();
   });
 });

test/token/ERC721/utils/ERC721Holder.test.js

@@ -1,22 +1,20 @@
+const { ethers } = require('hardhat');
 const { expect } = require('chai');
 
-const ERC721Holder = artifacts.require('$ERC721Holder');
-const ERC721 = artifacts.require('$ERC721');
-
-contract('ERC721Holder', function (accounts) {
-  const [owner] = accounts;
-
-  const name = 'Non Fungible Token';
-  const symbol = 'NFT';
-  const tokenId = web3.utils.toBN(1);
+const name = 'Non Fungible Token';
+const symbol = 'NFT';
+const tokenId = 1n;
 
+describe('ERC721Holder', function () {
   it('receives an ERC721 token', async function () {
-    const token = await ERC721.new(name, symbol);
+    const [owner] = await ethers.getSigners();
+
+    const token = await ethers.deployContract('$ERC721', [name, symbol]);
     await token.$_mint(owner, tokenId);
 
-    const receiver = await ERC721Holder.new();
-    await token.safeTransferFrom(owner, receiver.address, tokenId, { from: owner });
+    const receiver = await ethers.deployContract('$ERC721Holder');
+    await token.connect(owner).safeTransferFrom(owner, receiver, tokenId);
 
-    expect(await token.ownerOf(tokenId)).to.be.equal(receiver.address);
+    expect(await token.ownerOf(tokenId)).to.equal(receiver.target);
   });
 });

test/token/common/ERC2981.behavior.js

@@ -1,12 +1,10 @@
-const { BN, constants } = require('@openzeppelin/test-helpers');
+const { ethers } = require('hardhat');
 const { expect } = require('chai');
-const { ZERO_ADDRESS } = constants;
 
 const { shouldSupportInterfaces } = require('../../utils/introspection/SupportsInterface.behavior');
-const { expectRevertCustomError } = require('../../helpers/customError');
 
 function shouldBehaveLikeERC2981() {
-  const royaltyFraction = new BN('10');
+  const royaltyFraction = 10n;
 
   shouldSupportInterfaces(['ERC2981']);
 
@@ -16,64 +14,54 @@ function shouldBehaveLikeERC2981() {
     });
 
     it('checks royalty is set', async function () {
-      const royalty = new BN((this.salePrice * royaltyFraction) / 10000);
-
-      const initInfo = await this.token.royaltyInfo(this.tokenId1, this.salePrice);
-
-      expect(initInfo[0]).to.be.equal(this.account1);
-      expect(initInfo[1]).to.be.bignumber.equal(royalty);
+      expect(await this.token.royaltyInfo(this.tokenId1, this.salePrice)).to.deep.equal([
+        this.account1.address,
+        (this.salePrice * royaltyFraction) / 10_000n,
+      ]);
     });
 
     it('updates royalty amount', async function () {
-      const newPercentage = new BN('25');
+      const newFraction = 25n;
 
-      // Updated royalty check
-      await this.token.$_setDefaultRoyalty(this.account1, newPercentage);
-      const royalty = new BN((this.salePrice * newPercentage) / 10000);
-      const newInfo = await this.token.royaltyInfo(this.tokenId1, this.salePrice);
+      await this.token.$_setDefaultRoyalty(this.account1, newFraction);
 
-      expect(newInfo[0]).to.be.equal(this.account1);
-      expect(newInfo[1]).to.be.bignumber.equal(royalty);
+      expect(await this.token.royaltyInfo(this.tokenId1, this.salePrice)).to.deep.equal([
+        this.account1.address,
+        (this.salePrice * newFraction) / 10_000n,
+      ]);
     });
 
     it('holds same royalty value for different tokens', async function () {
-      const newPercentage = new BN('20');
-      await this.token.$_setDefaultRoyalty(this.account1, newPercentage);
+      const newFraction = 20n;
 
-      const token1Info = await this.token.royaltyInfo(this.tokenId1, this.salePrice);
-      const token2Info = await this.token.royaltyInfo(this.tokenId2, this.salePrice);
+      await this.token.$_setDefaultRoyalty(this.account1, newFraction);
 
-      expect(token1Info[1]).to.be.bignumber.equal(token2Info[1]);
+      expect(await this.token.royaltyInfo(this.tokenId1, this.salePrice)).to.deep.equal(
+        await this.token.royaltyInfo(this.tokenId2, this.salePrice),
+      );
     });
 
     it('Remove royalty information', async function () {
-      const newValue = new BN('0');
+      const newValue = 0n;
       await this.token.$_deleteDefaultRoyalty();
 
-      const token1Info = await this.token.royaltyInfo(this.tokenId1, this.salePrice);
-      const token2Info = await this.token.royaltyInfo(this.tokenId2, this.salePrice);
-      // Test royalty info is still persistent across all tokens
-      expect(token1Info[0]).to.be.bignumber.equal(token2Info[0]);
-      expect(token1Info[1]).to.be.bignumber.equal(token2Info[1]);
-      // Test information was deleted
-      expect(token1Info[0]).to.be.equal(ZERO_ADDRESS);
-      expect(token1Info[1]).to.be.bignumber.equal(newValue);
+      expect(await this.token.royaltyInfo(this.tokenId1, this.salePrice)).to.deep.equal([ethers.ZeroAddress, newValue]);
+
+      expect(await this.token.royaltyInfo(this.tokenId2, this.salePrice)).to.deep.equal([ethers.ZeroAddress, newValue]);
     });
 
     it('reverts if invalid parameters', async function () {
       const royaltyDenominator = await this.token.$_feeDenominator();
-      await expectRevertCustomError(
-        this.token.$_setDefaultRoyalty(ZERO_ADDRESS, royaltyFraction),
-        'ERC2981InvalidDefaultRoyaltyReceiver',
-        [ZERO_ADDRESS],
-      );
 
-      const anotherRoyaltyFraction = new BN('11000');
-      await expectRevertCustomError(
-        this.token.$_setDefaultRoyalty(this.account1, anotherRoyaltyFraction),
-        'ERC2981InvalidDefaultRoyalty',
-        [anotherRoyaltyFraction, royaltyDenominator],
-      );
+      await expect(this.token.$_setDefaultRoyalty(ethers.ZeroAddress, royaltyFraction))
+        .to.be.revertedWithCustomError(this.token, 'ERC2981InvalidDefaultRoyaltyReceiver')
+        .withArgs(ethers.ZeroAddress);
+
+      const anotherRoyaltyFraction = 11000n;
+
+      await expect(this.token.$_setDefaultRoyalty(this.account1, anotherRoyaltyFraction))
+        .to.be.revertedWithCustomError(this.token, 'ERC2981InvalidDefaultRoyalty')
+        .withArgs(anotherRoyaltyFraction, royaltyDenominator);
     });
   });
 
@@ -83,83 +71,78 @@ function shouldBehaveLikeERC2981() {
     });
 
     it('updates royalty amount', async function () {
-      const newPercentage = new BN('25');
-      let royalty = new BN((this.salePrice * royaltyFraction) / 10000);
-      // Initial royalty check
-      const initInfo = await this.token.royaltyInfo(this.tokenId1, this.salePrice);
+      const newFraction = 25n;
 
-      expect(initInfo[0]).to.be.equal(this.account1);
-      expect(initInfo[1]).to.be.bignumber.equal(royalty);
+      expect(await this.token.royaltyInfo(this.tokenId1, this.salePrice)).to.deep.equal([
+        this.account1.address,
+        (this.salePrice * royaltyFraction) / 10_000n,
+      ]);
 
-      // Updated royalty check
-      await this.token.$_setTokenRoyalty(this.tokenId1, this.account1, newPercentage);
-      royalty = new BN((this.salePrice * newPercentage) / 10000);
-      const newInfo = await this.token.royaltyInfo(this.tokenId1, this.salePrice);
+      await this.token.$_setTokenRoyalty(this.tokenId1, this.account1, newFraction);
 
-      expect(newInfo[0]).to.be.equal(this.account1);
-      expect(newInfo[1]).to.be.bignumber.equal(royalty);
+      expect(await this.token.royaltyInfo(this.tokenId1, this.salePrice)).to.deep.equal([
+        this.account1.address,
+        (this.salePrice * newFraction) / 10_000n,
+      ]);
     });
 
     it('holds different values for different tokens', async function () {
-      const newPercentage = new BN('20');
-      await this.token.$_setTokenRoyalty(this.tokenId2, this.account1, newPercentage);
+      const newFraction = 20n;
 
-      const token1Info = await this.token.royaltyInfo(this.tokenId1, this.salePrice);
-      const token2Info = await this.token.royaltyInfo(this.tokenId2, this.salePrice);
+      await this.token.$_setTokenRoyalty(this.tokenId2, this.account1, newFraction);
 
-      // must be different even at the same this.salePrice
-      expect(token1Info[1]).to.not.be.bignumber.equal(token2Info[1]);
+      expect(await this.token.royaltyInfo(this.tokenId1, this.salePrice)).to.not.deep.equal(
+        await this.token.royaltyInfo(this.tokenId2, this.salePrice),
+      );
     });
 
     it('reverts if invalid parameters', async function () {
       const royaltyDenominator = await this.token.$_feeDenominator();
-      await expectRevertCustomError(
-        this.token.$_setTokenRoyalty(this.tokenId1, ZERO_ADDRESS, royaltyFraction),
-        'ERC2981InvalidTokenRoyaltyReceiver',
-        [this.tokenId1.toString(), ZERO_ADDRESS],
-      );
 
-      const anotherRoyaltyFraction = new BN('11000');
-      await expectRevertCustomError(
-        this.token.$_setTokenRoyalty(this.tokenId1, this.account1, anotherRoyaltyFraction),
-        'ERC2981InvalidTokenRoyalty',
-        [this.tokenId1.toString(), anotherRoyaltyFraction, royaltyDenominator],
-      );
+      await expect(this.token.$_setTokenRoyalty(this.tokenId1, ethers.ZeroAddress, royaltyFraction))
+        .to.be.revertedWithCustomError(this.token, 'ERC2981InvalidTokenRoyaltyReceiver')
+        .withArgs(this.tokenId1, ethers.ZeroAddress);
+
+      const anotherRoyaltyFraction = 11000n;
+
+      await expect(this.token.$_setTokenRoyalty(this.tokenId1, this.account1, anotherRoyaltyFraction))
+        .to.be.revertedWithCustomError(this.token, 'ERC2981InvalidTokenRoyalty')
+        .withArgs(this.tokenId1, anotherRoyaltyFraction, royaltyDenominator);
     });
 
     it('can reset token after setting royalty', async function () {
-      const newPercentage = new BN('30');
-      const royalty = new BN((this.salePrice * newPercentage) / 10000);
-      await this.token.$_setTokenRoyalty(this.tokenId1, this.account2, newPercentage);
+      const newFraction = 30n;
 
-      const tokenInfo = await this.token.royaltyInfo(this.tokenId1, this.salePrice);
+      await this.token.$_setTokenRoyalty(this.tokenId1, this.account2, newFraction);
 
       // Tokens must have own information
-      expect(tokenInfo[1]).to.be.bignumber.equal(royalty);
-      expect(tokenInfo[0]).to.be.equal(this.account2);
+      expect(await this.token.royaltyInfo(this.tokenId1, this.salePrice)).to.deep.equal([
+        this.account2.address,
+        (this.salePrice * newFraction) / 10_000n,
+      ]);
+
+      await this.token.$_setTokenRoyalty(this.tokenId2, this.account1, 0n);
 
-      await this.token.$_setTokenRoyalty(this.tokenId2, this.account1, new BN('0'));
-      const result = await this.token.royaltyInfo(this.tokenId2, this.salePrice);
       // Token must not share default information
-      expect(result[0]).to.be.equal(this.account1);
-      expect(result[1]).to.be.bignumber.equal(new BN('0'));
+      expect(await this.token.royaltyInfo(this.tokenId2, this.salePrice)).to.deep.equal([this.account1.address, 0n]);
     });
 
     it('can hold default and token royalty information', async function () {
-      const newPercentage = new BN('30');
-      const royalty = new BN((this.salePrice * newPercentage) / 10000);
+      const newFraction = 30n;
 
-      await this.token.$_setTokenRoyalty(this.tokenId2, this.account2, newPercentage);
+      await this.token.$_setTokenRoyalty(this.tokenId2, this.account2, newFraction);
 
-      const token1Info = await this.token.royaltyInfo(this.tokenId1, this.salePrice);
-      const token2Info = await this.token.royaltyInfo(this.tokenId2, this.salePrice);
       // Tokens must not have same values
-      expect(token1Info[1]).to.not.be.bignumber.equal(token2Info[1]);
-      expect(token1Info[0]).to.not.be.equal(token2Info[0]);
+      expect(await this.token.royaltyInfo(this.tokenId1, this.salePrice)).to.not.deep.equal([
+        this.account2.address,
+        (this.salePrice * newFraction) / 10_000n,
+      ]);
 
       // Updated token must have new values
-      expect(token2Info[0]).to.be.equal(this.account2);
-      expect(token2Info[1]).to.be.bignumber.equal(royalty);
+      expect(await this.token.royaltyInfo(this.tokenId2, this.salePrice)).to.deep.equal([
+        this.account2.address,
+        (this.salePrice * newFraction) / 10_000n,
+      ]);
     });
   });
 }