PHP Testing

Priority: P1 (HIGH)

Core Rule Anchors

• [BE-TEST-01] Parameterized Tests for Equivalent Cases: Prefer #[DataProvider] (PHPUnit) or dataset (Pest) when methods have multiple equivalent inputs or boundary permutations. Distinct scenarios may stay separate test methods. Reviewers must not demand parameterized rewrites without a behavioral gap.
• [BE-TEST-02] Ban on Brittle DB Mock String Matching: Do not use string-matching mocks for raw SQL queries. Test pure domain calculations directly, or use SQLite in-memory / real DB for database repository verification.
• [BE-TEST-03] Ban on Shallow Assertions: Never assert only assertNotNull($result) without inspecting domain fields, status codes, and invariants.
• [BE-TEST-04] Ban on Pass-Through Interface Mocks: Repositories and service handlers must test contract compliance and error mapping. Ban 1:1 pass-through mock echoing without contract assertions.
• [BE-TEST-05] Bug-First Regression Lock: Every PR fixing a bug ticket or with title fix(...) must introduce a test reproducing the defect prior to the fix.

Write Tests with PHPUnit and Pest

• Standards: Use PHPUnit (9/10+) or Pest. Organize into Unit/, Integration/, and Feature/. Class names should extend TestCase.
• TDD Workflow ([BE-TEST-05]): Follow Red-Green-Refactor. Write failing test first, implement minimal logic, then refactor.
• Fluent Assertions ([BE-TEST-03]): Use assertSame (===) over assertEquals to avoid type coercion. Also use assertCount() and assertMatchesRegularExpression(). Avoid shallow assertions.
• Data Providers ([BE-TEST-01]): Use #[DataProvider('statusProvider')] (PHPUnit 10+) or dataset (Pest).
• Mocking & Isolation ([BE-TEST-02], [BE-TEST-04]): Use createMock() for dependencies; ban 1:1 pass-through mock echoing. Ensure tests are independent and repeatable. DB tests must use Transactions or SQLite :memory:.
• Coverage: Coverage is diagnostic and project-configured; verify risk-weighted critical paths rather than padding code for an arbitrary percentage.

Anti-Patterns

• [BE-TEST-01] Stylistic parameterized rewrites: Do not demand data provider rewrites without a behavioral gap.
• [BE-TEST-02] Brittle DB mock string matching: Do not match SQL strings in mocks.
• [BE-TEST-03] Shallow assertions: Never assert only assertNotNull without domain payload checks.
• [BE-TEST-04] Pass-through mock echoing: Ban 1:1 mock echoing without contract assertions.
• [BE-TEST-05] Bug fix without reproduction test: Ban bug fixes without a reproduction test.
• 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 over arbitrary percentage metrics.

References

• Testing Patterns & Mocks

Canonical response anchors

When this skill applies, preserve the following domain terminology or equivalent concrete examples in the answer when relevant:

• Define a static method returning test cases as arrays,method
• independent
• type coercion