Unit Testing Best Practices: Jest and React Testing Library Guide

Help me write effective unit tests for my React application using Jest and React Testing Library. I need: 1. TESTING PHILOSOPHY: - Testing pyramid: unit vs integration vs e2e (when to use each) - React Testing Library's core principle (test behavior, not implementation) - What NOT to test (implementation details, snapshot abuse) 2. SETUP AND CONFIGURATION: - jest.config.js setup for React with TypeScript - setupTests.ts with common extends and mocks - Custom render wrapper (for providers: Redux, Router, Theme) 3. TESTING PATTERNS WITH EXAMPLES: a) Component Rendering: - Render and assert visible text - Test with different prop combinations b) User Interactions: - Click, type, select using userEvent (not fireEvent) - Form submission testing - Keyboard navigation c) Async Testing: - waitFor, findBy queries for async state changes - Testing API calls with MSW (Mock Service Worker) - Loading and error states d) Custom Hooks: - renderHook usage - Testing state changes 4. COMMON ANTI-PATTERNS TO FIX: - Using getByTestId (prefer accessible queries) - Testing implementation details - Not cleaning up 5. COVERAGE GOALS: - What % coverage is meaningful - Which files/code paths matter most Provide code examples for each pattern above.