Create the first phpunit test

Note: phpunit9 doesn't support php8^, it compatible with php7.4

clone the repo: https://github.com/pcreem/psr-4Autoload
install phpunit $composer require --dev phpunit/phpunit ^9

$./vendor/bin/phpunit --version
PHPUnit 9.0.0 by Sebastian Bergmann and contributors.

$code composer.json

{
    "autoload": {
        "psr-4": {
            "App\\":"App/"
        }
    },
    "require-dev": {
        "phpunit/phpunit": "^9"
    }
}

$code App/Data/Database.php

<?php
namespace App\Data;

class Database {
    public function sayHi()
    {
        return 'create database\n';
    }
}

$code tests/DatabaseTest.php

<?php declare(strict_types=1);
use PHPUnit\Framework\TestCase;
use App\Data\Database;

final class DatabaseTest extends TestCase
{
    public function testCanCreateDatabase(): void
    {
        $database = new Database();
        $this->assertSame('create database\n', $database->sayHi());
    }
}

$./vendor/bin/phpunit --testdox tests

output

PHPUnit 9.5.4 by Sebastian Bergmann and contributors.

Database
 ✔ Can create database
the init

Time: 00:00.006, Memory: 4.00 MB

OK (1 test, 1 assertion)

repo: https://github.com/pcreem/theFirstPhpUnitTest