hardhat-zksync-chai-matchers

This plugin adds zkSync-specific capabilities to the Chai assertion library for testing smart contracts. It extends all the functionalities supported by the hardhat-chai-matchers plugin, with the idea to preserve the same behavior and interface. Currently, it is used in combination with local testing environment.

Changelog

Info

• Since responses from transactions that revert are highly dependent on the RPC implementation, all Hardhat chai matchers that start with revert have been affected (without any changes to the chai matchers interface).
• In addition, the options argument from changeEtherBalance/changeEtherBalances now includes the overrides field in order to support zksync-web3 transfer methods with overrides.

Installation

Add the latest version of this plugin to your project with the following command:

yarn add -D @matterlabs/hardhat-zksync-chai-matchers @nomicfoundation/hardhat-chai-matchers chai @nomiclabs/hardhat-ethers ethers

npm i -D @matterlabs/hardhat-zksync-chai-matchers

Usage

After installing it, add the plugin to your Hardhat config:

import "@matterlabs/hardhat-zksync-chai-matchers";

Then you'll be able to use the matchers in your tests.

changeEtherBalance

Assert that the ether balance of an address changed by a specific amount:

await expect(() =>
  sender.transfer({
    to: receiver.address,
    amount: 2000,
  })
).to.changeEtherBalance(sender.address, BigInt("-2000"));

await expect(() =>
  sender.sendTransaction({
    to: receiver.address,
    value: 1000,
  })
).to.changeEtherBalance(sender.address, "-1000");

This matchers include additional options argument with functionalities for including fee and overriding transaction:

overrides = {
  type: 2,
  maxFeePerGas: 1 * gasPrice,
  maxPriorityFeePerGas: 1 * gasPrice,
};

await expect(() =>
  sender.transfer({
    to: receiver.address,
    amount: 500,
    overrides,
  })
).to.changeEtherBalance(sender, -(txGasFees + 500), {
  balanceChangeOptions: {
    includeFee: true,
  },
  overrides,
});

changeTokenBalance

Assert that an ERC20 token balance of an address changed by a specific amount:

await expect(sender.transfer({ to: receiver.address, amount: 5, token: token.address })).to.changeTokenBalance(token, sender, -5);

await expect(token.transfer(receiver.address, 5)).to.not.changeTokenBalance(token, sender, 0);

reverted

Assert that a transaction reverted for any reason:

await expect(contract.setAmount(100)).to.be.reverted;

revertedWithCustomError

Assert that a transaction reverted with a specific custom error:

await expect(contract.setAmount(100)).to.be.revertedWithCustomError(contract, "InvalidAmount");

And you can also use regular chai matchers like:

emit

await expect(contract.setAmount(100)).to.emit(contract, "AmountUpdated");

properAddress

expect("0x36615Cf349d7F6344891B1e7CA7C72883F5dc049").to.be.properAddress;

Comparisons of numbers

expect(await contract.getAmount()).to.equal(100);

Checkout the advantages of using chai matchers here. Since the list of all supported chai matchers is same as with hardhat-chai-matchers plugin, check the reference documentation.