Setting sending account in Truffle test

Question

I need to create contracts from various accounts in a Truffle JS Test. To do so, I set:

let accounts = await web3.eth.getAccounts();
MyContract.web3.from = accounts[9];

Before creating my contract instance via:

let myContract = await MyContract.new("constructor argument");

However, the contract is still deployed by account 0 (accounts[0]).

How can I specify that that instance of MyContract shall be created using account 9?

I'm also interested in then calling functions of that contract using various accounts, so it's not just about deploying a contract using a specific account.

Answer 1

Try this:

let myContract = await MyContract.new("constructor argument", {from: accounts[9]});

Same thing for calling functions of that contract using various accounts.

You can use that object argument in order to specify various transaction details such as from, value, gas and gasPrice. It is optional (i.e., assigned default values if not specified explicitly), and it must therefore be provided after all mandatory arguments.

In your contract's code, those arguments will be available to the function via the implicit input argument called msg. For example, msg.sender will represent the value that you have passed in from, and msg.value will represent the value which you have passed in value.