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

function _transfer(address receiver_, uint256 payout) internal{

Testing in JavaScript Syntax. Expecting something like:

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

1 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!");
  • Thanks. Especially using web3.eth is very helpful: web3.js - Ethereum JavaScript API
    – Senju
    Jun 27, 2018 at 6:12
  • 1
    As an update to this answer, in current versions of web3 the BigNumber functionality used in this answer is now in web3.utils as web3.utils.toBN. Documentation Here Jul 6, 2019 at 5:23
  • If you're using ethers and hardhat, there's a convenient function there too: ethers.utils.formatEther(big_number_balance);
    – Olshansky
    Oct 17, 2021 at 20:25

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