Why deployed not called in test script?

[mghildiy]

In deploy script , we first call deploy and then deployed.

const simpleStorage = await simpleStorageFactory.deploy();
await simpleStorage.deployed();

I understand that deploy is like preparing the contract, assigning id etc to it, while actual deployment in network is done by deployed.

But in test script, we call deploy and then straightaway call contract's functions.

beforeEach(async function () {
    simpleStorageFactory = await ethers.getContractFactory("SimpleStorage");
    simpleStorage = await simpleStorageFactory.deploy();
  });

  it("should start with a favourite number of 0", async function () {
    const currentNumber = await simpleStorage.retrieve();

    assert.equal(currentNumber.toString(), "0");
  });

Why don't we invoke deployed in test script? Test also needs contract to be deployed, isn't?

[krakxn]

Your doubt is so because you have got things mixed up - below is a precise explanation which should answer your queries:

prototype . deploy ( … ) => Promise

Creates a transaction to deploy the transaction and sends it to the network using the contract Signer, returning a Promise that resolves to a Contract. The transaction is available as contract.deployTransaction.

Keep in mind that the Contract may not be mined immediately. The contract.deployed() function will return a Promise which will resolve once the contract is deployed, or reject if there was an error during deployment.

Simply, deploy is to deploy the contract and deployed to check if it worked correctly or not.

[mghildiy]

So I can put it as:

const contract = await factory.deploy // it would create transaction, send it to network , hands us contract-to-be-deployed(..and in the process of deployment)
await contract.deployed() // it tells whether its a  success or failure
await contract.deployTransaction.wait(6); // it would ensure that etherscan knows about the contract

So if .deployed() results in rejection then contract is basically just a contract but not deployed anywhere.

And because in test we are using test network, so we are pretty sure that contract is deployed after .deploy is called, hence we dont need to call .deployed.

[krakxn]

Docs: "The contract.deployed() function will return a Promise which will resolve once the contract is deployed, or reject if there was an error during deployment."

So, in Layman's terms: deployed() will be resolved/true if contract is deployed, but will be rejected/false if there is an error while deploying.

EDIT (for your edit): Yes, you got it. (whereas something like Rinkeby or mainnet takes time to mine blocks for our deployment transaction to go through). Hope this helps!

[mghildiy]

That helps surely, thanks.

[krakxn]

All the best with the course!