Lesson 9: Unit test for fulfillRandomWords is way too long, but how to break it up?

[webthethird]

Hello,

I just finished the unit tests in Lesson 9, and paused for a little while to see if I could break down that last one (i.e., "Picks a winner, sends them money and resets the lottery") into smaller pieces. That wasn't hard to do, but judging by the amount of time each of them takes, I'm not sure if it's an improvement.

Below you can see the output from the tests, along with how long they took:

Most of these smaller tests take as long to execute now as the entire thing did when it was one long it with many assert statements! Is there any way I could reorganize my code to bring the total executing time down closer to where it was before?

(Hopefully this isn't answered in the staging tests section, since I paused the video to post this question)

Below are the separated tests I wrote:

describe("Picks a winner, sends them money and resets the lottery", function () {
    let accounts,
        startingTimestamp,
        endingTimestamp,
        winnerStartingBalance,
        winnerEndingBalance
    const additionalEntrants = 3
    const startingAccountIndex = 1
    beforeEach(async function () {
        accounts = await ethers.getSigners()
        for (
            let i = startingAccountIndex;
            i < startingAccountIndex + additionalEntrants;
            i++
        ) {
            await raffle.connect(accounts[i]).enterRaffle({ value: entranceFee })
        }
        startingTimestamp = await raffle.getLastTimestamp()
    })

    it("Picks a winner", async function () {
        await new Promise(async (resolve, reject) => {
            // Setting up the listener
            raffle.once("WinnerPicked", async () => {
                try {
                    const recentWinner = await raffle.getRecentWinner()
                    assert.equal(recentWinner.toString(), accounts[1].address)
                } catch (e) {
                    reject(e)
                }
                resolve()
            })
            // Fire the event, so the listener will pick it up and resolve
            const tx = await raffle.performUpkeep([])
            const txReceipt = await tx.wait(1)
            await vrfCoordinatorV2Mock.fulfillRandomWords(
                txReceipt.events[1].args.requestId,
                raffle.address
            )
        })
    })
    it("Emits an Event when a winner is picked", async function () {
        const tx = await raffle.performUpkeep([])
        const txReceipt = await tx.wait(1)
        await expect(
            vrfCoordinatorV2Mock.fulfillRandomWords(
                txReceipt.events[1].args.requestId,
                raffle.address
            )
        ).to.emit(raffle, "WinnerPicked")
    })
    it("Resets the raffle state to open", async function () {
        await new Promise(async (resolve, reject) => {
            // Setting up the listener
            raffle.once("WinnerPicked", async () => {
                try {
                    const raffleState = await raffle.getRaffleState()
                    assert.equal(raffleState.toString(), "0")
                } catch (e) {
                    reject(e)
                }
                resolve()
            })
            // Fire the event, so the listener will pick it up and resolve
            const tx = await raffle.performUpkeep([])
            const txReceipt = await tx.wait(1)
            await vrfCoordinatorV2Mock.fulfillRandomWords(
                txReceipt.events[1].args.requestId,
                raffle.address
            )
        })
    })
    it("Updates the last timestamp", async function () {
        await new Promise(async (resolve, reject) => {
            // Setting up the listener
            raffle.once("WinnerPicked", async () => {
                try {
                    endingTimestamp = await raffle.getLastTimestamp()
                    assert(endingTimestamp > startingTimestamp)
                } catch (e) {
                    reject(e)
                }
                resolve()
            })
            // Fire the event, so the listener will pick it up and resolve
            const tx = await raffle.performUpkeep([])
            const txReceipt = await tx.wait(1)
            await vrfCoordinatorV2Mock.fulfillRandomWords(
                txReceipt.events[1].args.requestId,
                raffle.address
            )
        })
    })
    it("Resets the list of players", async function () {
        await new Promise(async (resolve, reject) => {
            // Setting up the listener
            raffle.once("WinnerPicked", async () => {
                try {
                    const numPlayers = await raffle.getNumPlayers()
                    assert.equal(numPlayers.toString(), "0")
                } catch (e) {
                    reject(e)
                }
                resolve()
            })
            // Fire the event, so the listener will pick it up and resolve
            const tx = await raffle.performUpkeep([])
            const txReceipt = await tx.wait(1)
            await vrfCoordinatorV2Mock.fulfillRandomWords(
                txReceipt.events[1].args.requestId,
                raffle.address
            )
        })
    })
    it("Transfers the winner all the funds", async function () {
        await new Promise(async (resolve, reject) => {
            // Setting up the listener
            raffle.once("WinnerPicked", async () => {
                try {
                    winnerEndingBalance = await accounts[1].getBalance()
                    assert.equal(
                        winnerEndingBalance.toString(),
                        winnerStartingBalance
                            .add(entranceFee.mul(additionalEntrants).add(entranceFee))
                            .toString()
                    )
                } catch (e) {
                    reject(e)
                }
                resolve()
            })
            // Fire the event, so the listener will pick it up and resolve
            const tx = await raffle.performUpkeep([])
            const txReceipt = await tx.wait(1)
            winnerStartingBalance = await accounts[1].getBalance()
            await vrfCoordinatorV2Mock.fulfillRandomWords(
                txReceipt.events[1].args.requestId,
                raffle.address
            )
        })
    })
})

[pyromaus]

I'm on the same part now, not 100% sure why it's taking your smaller tests longer but if I had to guess it's because you are now running your BeforeEach way more often, as opposed to just once,
So perhaps if you made that section run just once then maybe the whole test would take less time

[webthethird]

if I had to guess it's because you are now running your BeforeEach way more often, as opposed to just once, So perhaps if you made that section run just once then maybe the whole test would take less time

Yeah, I agree that it's probably the BeforeEach which takes so much time during each test. Only, I'm not familiar enough with Chai yet to know how to make that only run once when using multiple it blocks. It must be possible though, so I'll just have to learn more!