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How to get last block information in a Hardhat Waffle test?

I checked here https://hardhat.org/hardhat-network/#json-rpc-methods-support

And here https://hardhat.org/hardhat-network/reference/

it seems eth_blockNumber is what I need, but how can I use it to get the last block timestamp?

3 Answers 3

18

If you are using @nomiclabs/hardhat-ethers (and you are if you have @nomiclabs/hardhat-waffle installed and imported in your config), then:

const latestBlock = await hre.ethers.provider.getBlock("latest")

Notice that ethers.provider is something added by the @nomiclabs/hardhat-ethers plugin, it's not part of ethers itself. It's a provider that is connected to the network that Hardhat is using.

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  • 1
    Franco, thank you so much. I think "hre." is not needed :)
    – Russo
    Oct 4, 2021 at 8:24
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To answer:

how can I use it to get the last block timestamp?

And adding to the previous answer to get the timestamp just read the property from the returned block information:

const timeStamp = (await ethers.provider.getBlock("latest")).timestamp
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If you're using Hardhat and doing tests, you can get the timestamp of a block where a specific transaction was included

 it('should succeed - verify the timestamp when a token was minted', function () {
   const accounts = await ethers.getSigners()

   //mint something ~ the contract stores the block.timestamp during the mint

   expect(yourTx = await yourContract.connect(accounts[1]).mintNFT(
                randomParameters,
                moreRandomParameters,
                {value: yourMintPrice})).to.be.ok

   //Print timestamp from the specific block where a TX was included

   const foo = await ethers.provider.getBlock(yourTx.blockHash!)
   console.log(`timestamp of the tx ${foo.timestamp}`)

   //this function returns the token details stored in the contract

   const mintedToken = await yourContract.getTokenDetails(mintedTokenId)
   console.log(`tokenstoredTimestamp ${mintedToken.timestamp}`)


   expect(mintedToken.timestamp).to.be.equal(foo.timestamp)

        });

The previous answers are correct, this is just a different approach to get a bit more control if you are running parallel tests and your functions are time sensitive

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