PHP Testing

PHP Testing

Priority: P1 (HIGH)

Structure

tests/
├── Unit/
├── Integration/
└── Feature/

Implementation Guidelines

• Standards: Use PHPUnit (9/10+) or Pest. Organize into Unit/, Integration/, and Feature/. Class names should extend TestCase (e.g., class OrderServiceTest extends TestCase).
• TDD Workflow: Follow Red-Green-Refactor. Red: write failing test first for createOrder(), then Green: implement minimal logic to pass, then Refactor.
• Mocking: Use createMock(PaymentService::class) for dependencies. Define behavior with expects($this->once()) and method('charge') with with(100)->willReturn(true). DO NOT mock simple Data Objects.
• Fluent Assertions: assertSame checks type + value (===) — use assertSame('Test', $result->title) over assertEquals to avoid type coercion surprises. Also use assertCount() and assertMatchesRegularExpression().
• Data Providers: Use #[DataProvider('statusProvider')] (PHPUnit 10+) with a public static function statusProvider(): array or dataset (Pest).
• Isolation: Ensure tests are Independent and Repeatable. DB tests must use Transactions or SQLite :memory:.
• Pest syntax: Use it('creates an order', function() { ... }) and expect($result->title)->toBe('Test') for cleaner, more readable tests.
• Coverage: Aim for 80%+ line coverage. Use phpunit.xml to whitelist specific directories.
• Automation: Run tests on every PR using GitHub Actions or GitLab CI.

Anti-Patterns

• No testing private methods: Test through public interfaces only.
• No over-mocking internals: Mock only external boundaries.
• No real network/DB in unit tests: Use in-memory databases or mocks.
• No coverage-metric chasing: Prioritize meaningful assertions.

References

• Testing Patterns & Mocks