Solidity unit test

hello-world_test.sol

// SPDX-License-Identifier: GPL-3.0    
pragma solidity ^0.8.10;

// This import is automatically injected by Remix
import "remix_tests.sol"; 

// This import is required to use custom transaction context
// Although it may fail compilation in 'Solidity Compiler' plugin
// But it will work fine in 'Solidity Unit Testing' plugin
import "remix_accounts.sol";
import "../hello-world.sol";

// File name has to end with '_test.sol', this file can contain more than one testSuite contracts
contract testSuite {

    /// 'beforeAll' runs before all other tests
    /// More special functions are: 'beforeEach', 'beforeAll', 'afterEach' & 'afterAll'
    function beforeAll() public {
        // <instantiate contract>
        Assert.equal(uint(1), uint(1), "1 should be equal to 1");
    }

    function checkSuccess() public {
        // Use 'Assert' methods: https://remix-ide.readthedocs.io/en/latest/assert_library.html
        Assert.ok(2 == 2, 'should be true');
        Assert.greaterThan(uint(2), uint(1), "2 should be greater than to 1");
        Assert.lesserThan(uint(2), uint(3), "2 should be lesser than to 3");
    }

    function checkSuccess2() public pure returns (bool) {
        // Use the return value (true or false) to test the contract
        return true;
    }
    
    function checkFailure() public {
        Assert.notEqual(uint(1), uint(2), "1 should not be equal to 2");
    }

    /// Custom Transaction Context: https://remix-ide.readthedocs.io/en/latest/unittesting.html#customization
    /// #sender: account-1
    /// #value: 100
    function checkSenderAndValue() public payable {
        // account index varies 0-9, value is in wei
        Assert.equal(msg.sender, TestsAccounts.getAccount(1), "Invalid sender");
        Assert.equal(msg.value, 100, "Invalid value");
    }
}

contract MyTest {
    HelloWorld greeting;

    // beforeEach works before running each test
    function beforeEach() public {
        greeting = new HelloWorld();
    }

    /// Test if initial greeting is set correctly
    function initialMessage() public returns (bool) {
        return Assert.equal(greeting.get(), "Hello world!", "initial greeting is not correct");
    }

    /// Test if greeting is set as expected
    function messageChanges() public returns (bool) {
        greeting.set("Hello Confoo 2022!");
        return Assert.equal(greeting.get(), "Hello Confoo 2022!", "greeting is not right");
    }
}