Lesson 9: hh test - promise will not resolve

[knoori]

Problem is similar to #395.

Contract compiled & deployed successfully (https://rinkeby.etherscn.io/address/0x4f598A1aDF635b2CA690d197ccc1040F6eCCfbCc#code) using a 90s interval.

The VRF and Keeper work properly, the contract works correctly, and all the asserts/expects seem to pass (they don't throw an error and trigger the catch). However, my Promise will not resolve and the script gets stuck in the Promise.

const { assert, expect } = require("chai")
// const win = require("global")
const { network, getNamedAccounts, deployments, ethers } = require("hardhat")
// const { isCallTrace } = require("hardhat/internal/hardhat-network/stack-traces/message-trace")
const { networkConfig, developmentChains } = require("../../helper-hardhat-config")

developmentChains.includes(network.name)
    ? describe.skip
    : describe("Raffle staging tests", function () {
          let raffle, raffleEntranceFee, deployer
          //   Deploy contracts
          beforeEach(async function () {
              console.log("Retrieving and connecting to contract...")
              deployer = (await getNamedAccounts()).deployer
              raffle = await ethers.getContract("Raffle", deployer)
              raffleEntranceFee = await raffle.getEntranceFee()
              console.log("Connected")
          })

          describe("fulfillRandomWords", function () {
              it("Should use live Chainlink Keeper and VRF to pick a random winner, transfer funds, and reset the Raffle", async function () {
                  //   Enter the raffle
                  const startingTimestamp = await raffle.getLatestTimestamp()
                  const accounts = await ethers.getSigners()
                  await new Promise(async (resolve, reject) => {
                      // setup listener before actually entering raffle in case blockchain moves very fast
                      console.log("Setting up listener...")
                      raffle.once("WinnerPicked", async () => {
                          console.log("WinnerPicked event detected")
                          try {
                              const recentWinner = await raffle.getRecentWinner()
                              //   console.log("got winner") //DB
                              const raffleState = await raffle.getRaffleState()
                              //   console.log("got state") //DB
                              const winnerEndingBalance = await accounts[0].getBalance()
                              //   console.log("got balance") //DB
                              const endingTimestamp = await raffle.getLatestTimestamp()
                              //   console.log("got time") //DB
                              // asserts
                              console.log("Check empty players array")
                              await expect(raffle.getPlayer(0)).to.be.reverted // no players
                              console.log("Check winner")
                              assert.equal(recentWinner.toString(), accounts[0].address)
                              console.log("Check RaffleState")
                              assert.equal(raffleState, 0)
                              console.log("Check balances")
                              //   console.log(`Winner is ${recentWinner}`) //DB
                              //   console.log(`Pre balance is ${winnerPreBalance}`) //DB
                              //   console.log(`Starting balance is ${winnerStartingBalance}`) //DB
                              //   console.log(`Ending balance is ${winnerEndingBalance}`) //DB
                              assert.equal(
                                  winnerEndingBalance.toString(),
                                  winnerStartingBalance.add(raffleEntranceFee).toString()
                              )
                              console.log("Check timestamps")
                              assert(endingTimestamp > startingTimestamp)
                              console.log("Resolving promise")
                              resolve()
                              console.log("You shouldn't see me") //DB
                          } catch (error) {
                              console.log(error)
                              reject(error)
                          }
                      })
                      //   enter raffle
                      console.log("Entering raffle...")
                      const winnerPreBalance = await accounts[0].getBalance() //DB
                      const tx = await raffle.enterRaffle({ value: raffleEntranceFee })
                      const txReceipt = await tx.wait(1)
                      console.log("Awaiting winner via WinnerPicked event...")
                      const winnerStartingBalance = await accounts[0].getBalance()
                      //   this block won't complete until listener has detected event and resolved/rejected
                  })
              })
          })
      })

The event is detected, all the asserts are cleared, but resolve() doesn't exit the Promise. The script just gets stuck at the line after the resolve() statement:

❯ hh test --network rinkeby

  Raffle staging tests
    fulfillRandomWords
Retrieving and connecting to contract...
Connected
Setting up listener...
Entering raffle...
Awaiting winner via WinnerPicked event...
WinnerPicked event detected
Check empty players array
Check winner
Check RaffleState
Check balances
Check timestamps
Resolving promise
You shouldn't see me

I have a feeling I must be doing something stupid, but can't figure out what. Any help would be appreciated.

[DmitryLavrov]

To get an event "WinnerPicked" you should run vrfCoordinatorV2Mock.fulfillRandomWords

[PatrickAlphaC]

They are running this on a testnet so doesn't have to.

[PatrickAlphaC]

This is quite interesting. What if you put the resolve outside the try catch?

[knoori]

thanks for your reply. i tried moving the resolve outside the try/catch - the behavior is the same.

i just ran some more tests. interestingly, if i leave the test running it does eventually complete. it just takes a very long time (10-15 mins) while still executing the line after the resolve statement. this is true whether the resolve is inside or outside the try/catch (see example below for resolve outside the try/catch).

so at least the test is completing, but the duration of the test and the execution of the line after the resolve are puzzling. another thing that confuses me is that the "fulfillRandomWords" line, printed by the inner describe, gets printed before the "Retrieving contract..." and "Connected" lines, which are printed by the beforeEach block. maybe i don't properly understand beforeEach, but i would've expected the lines in this block to be printed before the inner describe is executed.

❯ hh test --network rinkeby

  Raffle staging tests
    fulfillRandomWords
Retrieving and connecting to contract...
Connected
Setting up listener...
Entering raffle...
Awaiting winner via WinnerPicked event...
WinnerPicked event detected
Check empty players array
Check winner
Check RaffleState
Check balances
Check timestamps
Resolving promise
You shouldn't see me
      ✓ Should use live Chainlink Keeper and VRF to pick a random winner, transfer funds, and reset the Raffle (38112119 gas)


  1 passing (10m)

[PatrickAlphaC]

Hmm... yeah rinkeby has been really slow lately... That's probably just it.

[PatrickAlphaC]

Rinkeby is being really slow.

[knoori]

thanks!