What problem does it solve? Writing reliable tests is hard: developers struggle to choose between unit, integration, and E2E tests, decide what to mock, and structure test suites that stay fast and maintainable. This Skill provides proven testing principles plus a script that detects and runs your project's test framework automatically. ## Core Features & Use Cases - Testing Strategy Guidance: Covers the testing pyramid, AAA pattern, test type selection, and when to use unit vs integration vs E2E tests. - Mocking & Test Data Patterns: Explains stubs, spies, mocks, and fakes, plus factories, fixtures, and builders for test data. - Unified Test Runner: The included Python script auto-detects Node.js (Jest, Vitest, npm test) or Python (pytest) projects, runs tests with optional coverage, and reports pass/fail counts as JSON. - Use Case: You are adding tests to a Node.js API project. Use this Skill to decide which endpoints need integration tests, how to mock the database layer, then run the test_runner script to execute Jest with coverage and get a structured summary. ## Quick Start Ask the assistant to review my test suite using the testing-patterns skill and run the test runner script on my project with coverage enabled.
