how to master openzeppelin access control

access.t.sol

pragma solidity ^0.8.13;

import "forge-std/Test.sol";

import {MyContract} from "../src/Access.sol";

contract AccessTest is Test {
    MyContract public myContract;
    address owner = address(0x100);
    address arbitrary = address(0x101);

    function setUp() public {
        //let's set address owner to msg.sender.
        vm.prank(owner);

        //create the contract.
        myContract = new MyContract();
    }

    function testAccessControl() public {
        //check the .owner() eq owner.
        assert(owner == myContract.owner());

        //use arbitrary address invoke specialThing() function.
        vm.prank(arbitrary);
        vm.expectRevert("Ownable: caller is not the owner");
        myContract.specialThing();

        //switch to owner.
        vm.prank(owner);
        myContract.specialThing();
    }
}