testing▌

Unit testing validates individual functions, methods, and classes in isolation by mocking all external dependencies.

When running Playwright tests from Claude Code or any CLI agent, always use minimal reporters to prevent verbose output from consuming the context window.

Modern TypeScript testing with Vite-native speed, ESM-first design, and instant HMR feedback. \n \n Vite-powered test execution delivers 10-100x faster performance than Jest through HMR-based test running and native ES module support \n Built-in TypeScript support requires zero configuration; includes Jest-compatible API for straightforward migration from existing test suites \n Supports React and Vue component testing via Testing Library and Vue Test Utils, with jsdom/happy-dom environment opti

Comprehensive Java testing with JUnit 5, Mockito, and integration testing frameworks. \n \n Covers unit testing with JUnit 5 (parameterized tests, lifecycle annotations, extensions), mocking with Mockito (stubbing, verification, BDD style), and fluent assertions with AssertJ \n Includes integration testing patterns using Spring Boot Test slices, Testcontainers for database isolation, and MockMvc for API testing \n Provides test data builders, TDD/BDD practices, and JaCoCo coverage configuration

Backtest trading strategies against historical data with performance metrics and parameter optimization. \n \n Includes 8 pre-built strategies (SMA, EMA, RSI, MACD, Bollinger Bands, Breakout, Mean Reversion, Momentum) for crypto and traditional assets \n Calculates comprehensive metrics: Sharpe, Sortino, Calmar ratios, max drawdown, VaR, volatility, win rate, and profit factor \n Supports parameter grid search optimization to find best strategy combinations \n Generates equity curves, trade logs

Expert knowledge for testing JavaScript/TypeScript projects using Vitest - a blazingly fast testing framework powered by Vite.

Unit and integration testing for Angular v20+ with Vitest or Jasmine, supporting signals and modern patterns. \n \n Supports both Vitest (recommended) and Jasmine test runners with native Angular v20+ integration via @angular/build \n Covers signal-based components, computed values, OnPush change detection, and input/output testing with modern APIs \n Includes HTTP mocking via HttpTestingController , service injection with TestBed.inject() , and dependency mocking with Vitest \n Provides pattern

Risk-based quality engineering strategy for modern software delivery.

Write failing tests first, then minimal code to pass, then refactor while keeping tests green. \n \n Follows the red-green-refactor cycle: write one failing test, verify it fails correctly, implement minimal code to pass, verify all tests pass, then refactor safely \n Requires watching each test fail before writing implementation code; tests that pass immediately prove nothing about correctness \n Applies to all new features, bug fixes, refactoring, and behavior changes; code written before test

Cross-browser end-to-end testing with auto-wait, parallel execution, and built-in debugging tools. \n \n Supports Chromium, Firefox, and WebKit across desktop and mobile devices with automatic element waiting and network control \n Includes role-based locators, page object model patterns, and storage-state authentication for maintainable test suites \n Offers visual regression testing via screenshot comparison, video recording, and trace viewer for debugging failed tests \n Built-in test runner