Truffle test: How to test Ether transfer? Balance of specific account?

Question

How is it possible to test if my contract actually transfers money to a specific account?

function _transfer(address receiver_, uint256 payout) internal{
    receiver_.transfer(payout);
}

Testing in JavaScript Syntax. Expecting something like:

assert.equal(accounts[1].balance, 100 Ether);

Answer 1

To assert the balance of an account, try this:

let expectedBalance = web3.toBigNumber(web3.toWei(3, 'ether'));
let actualBalance = await web3.eth.getBalance(accounts[1]);

assert.deepEqual(actualBalance, expectedBalance, "Balance incorrect!");