Sending transaction from different addresses in truffle test case

Question

I am having an admin in my contract who can do certain things. Here is the contract

function changeAdmin(address admin_) public {
    if (msg.sender != admin) revert();
    potentialAdmin = admin_;
}

function becomeAdmin() public {
     if(potentialAdmin==msg.sender) admin = msg.sender;
}

address public admin;

constructor() public{
      admin = msg.sender;
}

I am trying to test this using truffle framework. For this I need to pass an admin name from the contract creator and then call becomeAdmin from the address passed in first step. I am not able to clear this. Here is my test case

const te = artifacts.require("MyContract");

contract("Contract test cases", function() {

  it("should be able to change admin", async function() {

    var token = await te.deployed();

    var accounts = await web3.eth.getAccounts();

    var newAdmin = accounts[1];
    await token.changeAdmin.call(newAdmin, {from : accounts[0]});
    await token.becomeAdmin.call({from: newAdmin});

    var adminChanged = await token.admin.call();
    assert.equal(adminChanged, accounts[1], 'Admin set is wrong');

  });

});

Is the way of calling contract by passing different from addresses correct ?

Answer 1

In order to execute a state-changing function within a transaction, you need to use send.

On Truffle you can also omit it and let Truffle choose the default:

• call for constant functions (either pure or view)
• send for non-constant functions (neither pure nor view)

So in short, you need to change this:

    await token.changeAdmin.call(newAdmin, {from : accounts[0]});
    await token.becomeAdmin.call({from: newAdmin});

To this:

    await token.changeAdmin.send(newAdmin, {from : accounts[0]});
    await token.becomeAdmin.send({from: newAdmin});

Or to this:

    await token.changeAdmin(newAdmin, {from : accounts[0]});
    await token.becomeAdmin({from: newAdmin});