How to check if a function was fired

[Mahmood-Darwish]

Hi everyone.

I'm working on some tests for my project and I want to check the execution flow of my contract.

Basically, I want to call method A in my contract. It would make a vrf request (which I have mocked), the vrf then would call fulfillrandomwords, and fulfillrandomwords should call method B.

I want to call A and check if B was called. Not sure how to do that.

I messed around a lot with chai spies and I wasn't able to get it working. I have the following code:

it("Calls the right game", async () => {
    const bet = await game.MINIMUM_BET()
    const spy = await chai.spy.on(game, "blackOrRed")

    await game.play(0, deployer.address, 5, 5, {
        value: bet,
    })
    await VRFCoordinatorV2Mock.fulfillRandomWords(1, game.address)

    expect(spy).to.have.been.called.once
})

play is method A and blackOrRed is method B. This test always fails even if I put const spy = chai.spy.on(game, "play") which it obviously shouldn't since I'm literally calling it by hand.

[rin-st]

you can use events.

emit SomeEvent(); on your solidity contract, and

contract.on("SomeEvent", () => {
    // do something here
}

in your tests.

(13:54:02) Introduction to Events

[Mahmood-Darwish]

This definitely works, but I was hoping to do it without introducing events that will only be used for testing.

[rin-st]

I may be wrong, but as I understand it's a common way to write tests in your case.
If your method B changes some state you can just check that state.

[alymurtazamemon]

@Mahmood-Darwish You can use the hardhat console contract for it.

Import the contract in your contract

import "hardhat/console.sol";

After that use console.log anywhere you want inside the contract.