Testing – How to Test for Custom Error Reverts in Hardhat with Detailed Steps

This example shows how to work with events in Hardhat in general, and it includes a test that illustrates some scenarios.

The tl;dr is that, given a contract like this one:

contract EventEmitter {
  event MyEventWithData(uint, string);

  function emitMyEventWithData(uint x, string calldata s) public {
    emit MyEventWithData(x, s);
  }
}

You can check it in a test like this (notice that this relies on hardhat-waffle):

  it("Should emit MyEventWithData", async function () {
    const EventEmitter = await ethers.getContractFactory("EventEmitter");
    const eventEmitter = await EventEmitter.deploy();
    await eventEmitter.deployed();

    await expect(eventEmitter.emitMyEventWithData(42, "foo"))
      .to.emit(eventEmitter, "MyEventWithData")
      .withArgs(42, "foo");
  });

Afaik hardhat test spins up their own test network, unless you specify it in the hardhat config.

Alternatively you should be able specify explicitly that hardhat should use your local hardhat node (e.g. http://localhost:8545) by adding --network localhost. See https://hardhat.org/hardhat-network/#running-stand-alone-in-order-to-support-wallets-and-other-software