evm_increaseTime()

[usman571]

i don't understand how actually these two lines of code works.

          await network.provider.send("evm_increaseTime", [interval.toNumber() + 1])
          await network.provider.request({ method: "evm_mine", params: [] })

[pacelliv]

Hello @usman571.

• evm_increaseTime is a method that jumps in time, it takes one argument, which is the amount of seconds to increase the timestamp in our local network.
• In order for the adjustment in time to be effective, we need to manually mine a block with the method evm_mine.

These methods only work in our local network.

[alymurtazamemon]

@pacelliv Here we are using Hardhat for testing so this is the correct reference LINK

[usman571]

why we need this in this whole test

  describe("performUpkeep", () => {
              it("can only run if checkupkeep is true", async () => {
                  await raffle.enterRaffle({ value: raffleEntranceFee })
                  await network.provider.send("evm_increaseTime", [interval.toNumber() + 1])
                  await network.provider.request({ method: "evm_mine", params: [] })
                  const tx = await raffle.performUpkeep("0x")
                  assert(tx)
              })
              it("reverts if checkup is false", async () => {
                  await expect(raffle.performUpkeep("0x")).to.be.revertedWith(
                      "Raffle__UpkeepNotNeeded"
                  )
              })
              it("updates the raffle state and emits a requestId", async () => {
                // Too many asserts in this test!
                await raffle.enterRaffle({ value: raffleEntranceFee })
                await network.provider.send("evm_increaseTime", [interval.toNumber() + 1])
                await network.provider.request({ method: "evm_mine", params: [] })
                const txResponse = await raffle.performUpkeep("0x") // emits requestId
                const txReceipt = await txResponse.wait(1) // waits 1 block
                const raffleState = await raffle.getRaffleState() // updates state
                const requestId = txReceipt.events[1].args.requestId
                assert(requestId.toNumber() > 0)
                assert(raffleState == 1) // 0 = open, 1 = calculating
            })
          })

[alymurtazamemon]

@usman571 In the performUpkeep function we are calling the checkUpkeep function which is using this bool timePassed = ((block.timestamp - s_lastTimeStamp) > i_interval); condition inside it.

But this condition is using the timestamp which will occur in the future. Now on the real blockchain we cannot increase the time of blockchain or mine new blocks our self but because we are using the Hardhat which provide these methods to increase the blockchain time and mine blocks so we can test these type of conditions in smart contracts.

And here increasing time is important because when checkUpkeep function will return true only then we can test further things inside performUpkeep function. Due to that, we are first making sure that checkUpkeep returning true and then checking other things.

[usman571]

Thank you bro, i got it

[pacelliv]

@alymurtazamemon I don't understand I don't see any definition for these methods in the link, Hardhat references Ganache.