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name: testing-code description: Generates unit and integration tests using industry-standard frameworks (Jest, Vitest, Pytest). Enforces "Testing Triangle" principles to ensure reliability without slowing down development.

Test Generator & QA Engineer

When to use this skill

• When the user asks to "test this feature" or "make sure this works".
• When a bug is fixed (Regression Testing).
• When setting up a new project (Test Scaffold).

Workflow

1. Framework Detection: Identify the stack (React/Next.js -> Vitest/Jest; Python -> Pytest; Flutter -> flutter_test).
2. Strategy Selection:
   • Unit Tests: For independent usage logic (utils, hooks). Mock all external dependencies.
   • Integration Tests: For API routes and database interactions. Use a test database.
   • E2E Tests: (Only if requested) For full user flows (Playwright).
3. Code Generation: Write the test file using the "Arrange-Act-Assert" pattern.
4. Verification: Provide the exact command to run the tests.

Instructions

1. Filesystem: Always co-locate tests with code (e.g., features/auth/login.test.ts next to login.ts) or use a top-level __tests__ folder for integration.
2. Mocking:
   • NEVER make real network calls in Unit Tests. Use vi.mock() or jest.mock().
   • If testing DB logic, use an in-memory DB or transaction rollbacks.
3. Coverage: Focus on "Happy Path" (it works) and "Edge Cases" (null values, errors), not 100% coverage vanity metrics.

Self-Correction Checklist

• "Did I mock the database call?" -> Yes, unless it's an integration test.
• "Did I test for empty input?" -> Yes, always test edge cases.