Foundry Authorization (Solidity Code Example)

// SPDX-License-Identifier: MIT
pragma solidity 0.8.26;

import {Test, console2, stdError} from "forge-std/Test.sol";

contract Auth {
    address public owner;

    constructor() {
        owner = msg.sender;
    }

    function setOwner(address _owner) external {
        require(msg.sender == owner, "not authorized");
        owner = _owner;
    }
}

contract AuthTest is Test {
    Auth private auth;

    function setUp() public {
        // owner = this contract
        auth = new Auth();
    }

    function testSetOwner() public {
        auth.setOwner(address(1));
        assertEq(auth.owner(), address(1));
    }

    function testFailNotOwner() public {
        // Next call will be called by address(1)
        vm.prank(address(1));
        auth.setOwner(address(1));

        vm.startPrank(address(1));
        // All calls until stopPrank will be made by address(1)
        auth.setOwner(address(1));
        auth.setOwner(address(1));
        auth.setOwner(address(1));
        vm.stopPrank();
    }
}