类：MockTracker

【Class: MockTracker】

MockTracker 类用于管理模拟功能。测试运行器模块提供了一个顶层的 mock 导出，它是一个 MockTracker 实例。每个测试也通过测试上下文的 mock 属性提供其自身的 MockTracker 实例。

【The MockTracker class is used to manage mocking functionality. The test runner module provides a top level mock export which is a MockTracker instance. Each test also provides its own MockTracker instance via the test context's mock property.】