Не пишите бесполезные unit-тесты

class Users
{
    public function __construct(PDO $pdo)
    {
        $this->pdo = $pdo;
    }

    public function getAllUsers()
    {
        $stmt = $this->pdo->prepare('SELECT * FROM users');
        return $stmt->fetchAll();
    }
}

class UserTest extends TestCase
{
    public function testGetAllUsers()
    {
        $pdo = m::mock(PDO::class);
        $stmt = m::mock(PDOStatement::class);

        $pdo->shouldReceive(‘prepare’)->andReturn($stmt);
        $pdoStmt->shouldReceive(‘fetchAll’)->andReturn($userArray);

        $users = new Users($pdo);
        $result = $users->getAllUsers();

        $this->assertEquals($userArray, $users);
    }
}