hardhat-chai-matchers-viem

This plugin is based on the existing @nomicfoundation/hardhat-chai-matchers. If you are using ethers, you should use that instead.

Installation

bun add @ensdomains/hardhat-chai-matchers-viem

In your hardhat config:

import("@ensdomains/hardhat-chai-matchers-viem");

Getting started

Deploy contracts with deployContract and pass them into expect to use matchers from this plugin:

import { expect } from "chai";
import hre from "hardhat";

it("works", async () => {
  const example = await hre.viem.deployContract("ExampleContract", []);
  await expect(example)
    .write("revertWithSomeCustomError")
    .toBeRevertedWithCustomError("SomeCustomError");
});

To speed up tests, you should use hardhat fixtures:

import { loadFixture } from "@nomicfoundation/hardhat-network-helpers";
import { expect } from "chai";
import hre from "hardhat";

async function deployExample() {
  const example = await hre.viem.deployContract("ExampleContract", []);
  return example;
}

it("works", async () => {
  const example = await loadFixture(deployExample);
  await expect(example)
    .write("revertWithSomeCustomError")
    .toBeRevertedWithCustomError("SomeCustomError");
});

Available matchers

• expect(contract).read(...)
• expect(contract).write(...)
• expect(contract).transaction(...)
• .toBeReverted()
• .toBeRevertedWithCustomError(...)
  • .withArgs(...)
• .toBeRevertedWithoutReason()
• .toBeRevertedWithPanic(...)
• .toBeRevertedWithString(...)
• .toEmitEvent(...)
  • .withArgs(...)
• .toEmitEventFrom(...)
  • .withArgs(...)