test-strategy-document

## Purpose Produce a testing strategy document (`test-strategy.md`) that details the quality assurance processes, testing layers, test environments, and automated pipeline rules of a software project. This ensures development and QA teams test systematically and maintain high software reliability. ## Input **Works best with:** The name or description of the product/service, along with target quality goals. **Also valuable:** Codebase tech stack, critical integrations (e.g. payment processors, external APIs), test runners in use (e.g. PHPUnit, Vitest, Playwright), CI/CD runner environments. **Example invocation:** `Create a testing strategy for our ledger-based payment processing module. It is built in PHP 8.3 with PHPUnit. It connects to the bank gateway via API and updates database tables. Needs unit tests with database mocks, integration tests with Docker DB fixtures, and E2E checkout runs using Playwright. Target coverage is 80% on the core domain.` ## Key Concepts ### 1. The Agile Testing Pyramid Distribute tests to optimize run speed and coverage: - **Unit Tests (Base, ~70%)**: Test isolated components, helper classes, and domain logic. Run in milliseconds. External calls are mocked out. - **Integration Tests (Middle, ~20%)**: Test the interaction between components, repositories, and database schemas. Connect to a local test database or simulated service. - **End-to-End (E2E) Tests (Top, ~10%)**: Test the entire application flow through the user interface (e.g. br...