[Ethereum] How to get contract’s ether balance at hardhat / waffle

ethers.jshardhatunittesting

I writing hardhat/ethers/waffle unit tests for my contract and need to know Ether balance of my contract.

Chai matcher changeEtherBalance needs Signer object to check balance, but I have address of my contract only.

I know, what ethers.js has provider object with getBalance(address) method, so I have installed nomiclabs-hardhat-ethers plugin and can call
ethers.provider.getBalance(address)

It works well for addresses from signers ethers.getSigners() but returns 0 for mycontract.address.

How I can know my contract Ethereum balance?
Please advice.

Best Answer

const { ethers, waffle} = require("hardhat");
const provider = waffle.provider;
const balance0ETH = await provider.getBalance(user1.address);

Related Solutions

Ether.js – Impersonating a Contract When Calling Another in Tests

contract.signer returns the signer of the contract deployer account, not the signer of the contract's own address. It's going to be really difficult to impersonate an account address, as the impersonated account would need to contain ETH to pay for the any transaction generated through it. So I would imaging you would first need to expect what the contract address would be (maybe using CREATE2), and then send it some ETH, then create the contract at that address you sent ETH to and impersonate it to generate that transaction. If you do it the other way around, the contract address most likely would have a fallback function to refuse accepting any sent ETH. You'll need to use Hardhat to be able to impersonate an account, here's how to do it: https://hardhat.org/hardhat-network/reference/#hardhat-impersonateaccount

Solidity Testing – Is Waffle an Obsolete Library?

Waffle is very useful for mocking functions of smart contracts, without the need to write a new fake contract. Other things could probably be done with normal etherjs and chai.

Mock contract example:

const { waffle, ethers } = require('hardhat');
const { deployMockContract, provider } = waffle;

...code

  const mockERC20 = await deployMockContract(<params>);
  await mockERC20.mock.transfer.reverts();
  --> test something
  await mockERC20.mock.transferFrom.returns(true);
  --> test something

Best Answer

Related Solutions

Ether.js – Impersonating a Contract When Calling Another in Tests

Solidity Testing – Is Waffle an Obsolete Library?

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