Jest testing patterns, factory functions, mocking strategies, and TDD workflow. Use when writing unit tests, creating test factories, or following TDD red-green-refactor cycle.

Jest 测试模式、工厂函数、模拟策略和 TDD 工作流。适用于编写单元测试、创建测试工厂或遵循 TDD 红绿重构循环。