fakeExample.php

<?php
class AuthorizerFake implements Authorizer {
  public $allowedUsers = [
      'test_user' => '123456',
      'test_admin' => '123456'
  ];
  public authorize($username, $password) {
    return array_key_exists($this->allowedUsers, $username) 
        && $this->allowedUsers[$username] === $password;
  }
}