How to write unit test in hardhat?

Question

I´m new to solidity and wonder how I`m writing a uint test for this contract in hardhat:

//SPDX-License-Identifier: Unlicense
pragma solidity ^0.8.0;

import "@openzeppelin/contracts/utils/Counters.sol";
import "@openzeppelin/contracts/token/ERC721/extensions/ERC721URIStorage.sol";

contract Web3 is ERC721URIStorage {
    uint256 Web3_Token_ID;

    constructor() ERC721("Web3NFT", "Web3N") {}

    function mintNFT(
        address _userOne,
        address _userTwo,
        string memory tokenURI
    ) public {
        _mint(_userOne, Web3_Token_ID);
        _setTokenURI(Web3_Token_ID, tokenURI);
        Web3_Token_ID++;

        _mint(_userTwo, Web3_Token_ID);
        _setTokenURI(Web_Token_ID, tokenURI);
        Web3_Token_ID++;
    }
}

Answer 1

When you create a new hardhat project there is a really good example test.

The docs also explain it step by step https://hardhat.org/tutorial/testing-contracts

You can run the test for the default greeter contract in the project by running npx hardhat test

For your specific test first I'd check that Web3_Token_ID is 0, that _userOne and _userTwo balance is 0 (by using balanceOf(_userOne) on the contract), then call your mint() function, and checking the same balances and Web3_Token_ID again to see if they were updated properly