Raffle Staging Test Assertion Error.

[Abhisek0x]

I think in staging test we are not considering the Gas Cost while asserting Winner Ending Balance and Starting Balance so how did it work in the video when Patrick Tested it???

Error

  Raffle Unit Tests   
    fulfillRandomWords
Setting up test...
Setting up Listener...
Entering Raffle...
Ok, time to wait...
WinnerPicked event fired!
AssertionError: expected '4703925565609306917' to equal '4714098146533796765'
    at FragmentRunningEvent.<anonymous> (C:\Users\AY\Desktop\Raffle_Lottery\test\unit\raffle.staging.test.js:39:38)
    at processTicksAndRejections (node:internal/process/task_queues:96:5) {
  showDiff: true,
  actual: '4703925565609306917',
  expected: '4714098146533796765',
  operator: 'strictEqual'
}

const { assert, expect } = require("chai")
const { getNamedAccounts, deployments, ethers, network } = require("hardhat")
const { developmentChains, networkConfig } = require("../../helper-hardhat-config")

developmentChains.includes(network.name)
    ? describe.skip
    : describe("Raffle Unit Tests", function () {
          let raffle, raffleEntranceFee, deployer

          beforeEach(async function () {
              deployer = (await getNamedAccounts()).deployer
              raffle = await ethers.getContract("Raffle", deployer)
              raffleEntranceFee = await raffle.getEntranceFee()
          })

          describe("fulfillRandomWords", function () {
              it("works with live Chainlink Keepers and Chainlink VRF, we get a random winner", async function () {

                  console.log("Setting up test...")
                  const startingTimeStamp = await raffle.getLastTimeStamp()
                  const accounts = await ethers.getSigners()

                  console.log("Setting up Listener...")
                  await new Promise(async (resolve, reject) => {
                    
                      raffle.once("WinnerPicked", async () => {
                          console.log("WinnerPicked event fired!")
                          try {
                             
                              const recentWinner = await raffle.getRecentWinner()
                              const raffleState = await raffle.getRaffleState()
                              const winnerEndingBalance = await accounts[0].getBalance()
                              const endingTimeStamp = await raffle.getLastTimeStamp()

                              await expect(raffle.getPlayers(0)).to.be.reverted
                              assert.equal(recentWinner.toString(), accounts[0].address)
                              assert.equal(raffleState, 0)
                              assert.equal(
                                  winnerEndingBalance.toString(),
                                  winnerStartingBalance.add(raffleEntranceFee).toString()
                              )
                              assert(endingTimeStamp > startingTimeStamp)
                              resolve()
                          } catch (error) {
                              console.log(error)
                              reject(e)
                          }
                      })
               
                      console.log("Entering Raffle...")
                      await raffle.enterRaffle({ value: raffleEntranceFee })
                      console.log("Ok, time to wait...")
                      const winnerStartingBalance = await accounts[0].getBalance()

                  })
              })
          })
      })

[knoori]

The transaction await raffle.enterRaffle({ value: raffleEntranceFee }) transfers the raffleEntranceFee to the Raffle contract and also costs some gas. Since const winnerStartingBalance = await accounts[0].getBalance() is executed after the transaction, in principle winnerStartingBalance should already include the gas cost.

However, in my case, winnerStartingBalance was not reflecting the updated account balance - possibly because the enterRaffle transaction wasn't being mined fast enough (?) - leading the to the same starting/ending balance assertion error that you're seeing.

I fixed the issue by modifying the code

console.log("Entering Raffle...")
const tx = await raffle.enterRaffle({ value: raffleEntranceFee })
const txReceipt = await tx.wait(1)
console.log("Ok, time to wait...")
const winnerStartingBalance = await accounts[0].getBalance()

We're now explicitly waiting for the transaction to be mined/confirmed before checking the account balance. After doing this, winnerStartingBalance gives the correct value (i.e. the original account balance - entrance fee - gas cost), and the assertion holds.

Hope that helps.

[Equious]

I've watched my wallet balance leave and return - from what I can tell, the starting balance is being set higher than it should be. I wondered if the transaction for the payment was taking too long or something. I'll try waiting for a confirmation.

[PatrickAlphaC]

I'm having a hard time reproducing... yes, adding waits on our transactions is for sure what we want to be doing. Does anyone want to make a PR?

[PatrickAlphaC]

Ah, I updated it actually.

[SlothXGreaver]

@knoori , you were right all along.
When I saw your fix:

console.log("Entering Raffle...")
const tx = await raffle.enterRaffle({ value: raffleEntranceFee })
const txReceipt = tx.wait(1)
console.log("Ok, time to wait...")
const winnerStartingBalance = await accounts[0].getBalance()

I saw your line:
const txReceipt = tx.wait(1)
My VSCode was saying txReceipt was being declared, but not used.
So, in my wisdom, I shortened the line to:
tx.wait(1) instead of await tx.wait(1)
Thank you (and Patrick of course) for being here, hope to do the same soon for other people!!

[knoori]

glad it worked! you're right, it should be await tx.wait(1) and not just tx.wait(1), and the txResponse variable is unnecessary. i edited my comment.