통합 테스트와 기능 테스트

단위 테스트를 넘어서

테스트 피라미드

통합 테스트: 실제 데이터베이스를 대상으로 하는 저장소

<?php
use PHPUnit\Framework\TestCase;

final class UserRepositoryTest extends TestCase
{
    private \PDO $pdo;

    protected function setUp(): void
    {
        $this->pdo = new \PDO('sqlite::memory:');
        $this->pdo->setAttribute(\PDO::ATTR_ERRMODE, \PDO::ERRMODE_EXCEPTION);
        $this->pdo->exec('CREATE TABLE users (id INTEGER PRIMARY KEY, email TEXT)');
    }

    public function test_persists_and_finds_a_user(): void
    {
        $repo = new UserRepository($this->pdo);
        $id = $repo->create('ada@example.com');
        self::assertSame('ada@example.com', $repo->find($id)->email);
    }
}

격리: 트랜잭션 롤백

<?php
protected function setUp(): void
{
    $this->pdo = TestDb::connection();
    $this->pdo->beginTransaction();
}

protected function tearDown(): void
{
    $this->pdo->rollBack();   // undo everything this test did
}

픽스처와 팩토리

<?php
final class UserFactory
{
    public static function create(\PDO $pdo, array $overrides = []): int
    {
        $data = array_merge(['email' => 'user'.uniqid().'@test.dev'], $overrides);
        $stmt = $pdo->prepare('INSERT INTO users (email) VALUES (:email)');
        $stmt->execute($data);
        return (int) $pdo->lastInsertId();
    }
}

기능 테스트: 클라이언트처럼 애플리케이션 호출하기

<?php
use Symfony\Bundle\FrameworkBundle\Test\WebTestCase;

final class HealthControllerTest extends WebTestCase
{
    public function test_health_endpoint_returns_ok(): void
    {
        $client = static::createClient();
        $client->request('GET', '/health');

        self::assertResponseIsSuccessful();        // 2xx
        self::assertJson($client->getResponse()->getContent());
    }
}

응답 검증하기

<?php
public function test_creating_a_user_persists_it(): void
{
    $client = static::createClient();
    $client->request('POST', '/users', server: [
        'CONTENT_TYPE' => 'application/json',
    ], content: json_encode(['email' => 'ada@example.com']));

    self::assertResponseStatusCodeSame(201);

    $repo = static::getContainer()->get(UserRepository::class);
    self::assertNotNull($repo->findByEmail('ada@example.com'));
}

외부 경계만 선택적으로 가짜 처리하기

<?php
public function test_checkout_charges_via_gateway(): void
{
    $client = static::createClient();
    // Replace the real gateway binding with an in-memory fake:
    static::getContainer()->set(PaymentGateway::class, new FakePaymentGateway());

    $client->request('POST', '/checkout', content: json_encode(['cart' => 1]));
    self::assertResponseIsSuccessful();
}

테스트 모음은 분리하고 실행 속도도 나누기

<phpunit>
  <testsuites>
    <testsuite name="unit">
      <directory>tests/Unit</directory>
    </testsuite>
    <testsuite name="integration">
      <directory>tests/Integration</directory>
    </testsuite>
    <testsuite name="functional">
      <directory>tests/Functional</directory>
    </testsuite>
  </testsuites>
</phpunit>

커버리지보다 결정성이 중요합니다

테스트 데이터베이스를 운영 환경과 일치시키기

<?php
// Read connection from environment so CI points at a real Postgres/MySQL container
$dsn = getenv('TEST_DATABASE_URL') ?: 'sqlite::memory:';
$pdo = new \PDO($dsn);
$pdo->setAttribute(\PDO::ATTR_ERRMODE, \PDO::ERRMODE_EXCEPTION);
// In CI, TEST_DATABASE_URL targets the same engine as production.

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