如何在测试中模拟外部依赖关系?

本文介绍了如何在测试中模拟外部依赖关系?的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我已经在实现中使用外部包装箱对汽车进行了建模和实现:

I've modeled and implemented a car using an extern crate inside the implementation:

extern crate speed_control; struct Car; trait SpeedControl { fn increase(&self) -> Result<(), ()>; fn decrease(&self) -> Result<(), ()>; } impl SpeedControl for Car { fn increase(&self) -> Result<(), ()> { match speed_control::increase() { // Here I use the dependency // ... } } // ... }

我想测试上面的实现，但是在我的测试中，我不想让speed_control::increase()像生产时那样运行-我想对其进行模拟.我该如何实现?

I want to test the implementation above, but in my tests I don't want speed_control::increase() to behave like it was in production - I want to mock it. How can I achieve this?

推荐答案

我建议您将后端功能speed_control::increase包装为某些特征:

I would suggest you wrap the back-end function speed_control::increase in some trait:

trait SpeedControlBackend { fn increase(); } struct RealSpeedControl; impl SpeedControlBackend for RealSpeedControl { fn increase() { speed_control::increase(); } } struct MockSpeedControl; impl SpeedControlBackend for MockSpeedControl { fn increase() { println!("MockSpeedControl::increase called"); } } trait SpeedControl { fn other_function(&self) -> Result<(), ()>; } struct Car<T: SpeedControlBackend> { sc: T, } impl<T: SpeedControlBackend> SpeedControl for Car<T> { fn other_function(&self) -> Result<(), ()> { match self.sc.increase() { () => (), } } }