模拟对象 - 设置方法 - 测试驱动开发 [英] Mock objects - Setup method - Test Driven Development

问题描述

我正在学习测试驱动开发并尝试使用 Moq 库进行模拟.Mock类的Setup方法的作用是什么?

I am learning Test Driven Development and trying to use Moq library for mocking. What is the purpose of Setup method of Mock class?

推荐答案

Moq Mock 对象的默认行为是存根所有方法和属性.这意味着使用任何参数对该方法/属性的调用都不会失败，并将返回特定返回类型的默认值.

The default behaviour of a Moq Mock object is to stub all methods and properties. This means that a call to that method/property with any parameters will not fail and will return a default value for the particular return type.

您出于以下任何或所有原因调用 Setup 方法:

You call Setup method for any or all of the following reasons:

• 您想限制方法的输入值.

public interface ICalculator {
  int Sum(int val1, val2);
}

var mock = new Mock<ICalculator>();
mock.Setup(m=>m.Sum(
  It.IsAny<int>(), //Any value
  3                //value of 3
));

上述设置将匹配对 Sum 方法的调用，其中 val1 和 val2 的任何值为 3.

The above setup will match a call to method Sum with any value for val1 and val2 value of 3.

• 您想要返回一个特定的值.继续 ICalculator 示例，无论输入参数如何，以下设置都将返回值 10:

• You want to return a specific value. Continuing with ICalculator example, the following setup will return a value of 10 regardless of the input parameters:

var mock = new Mock<ICalculator>();
mock.Setup(m=>m.Sum(
  It.IsAny<int>(), //Any value
  It.IsAny<int>()  //Any value
)).Returns(10);

• 您想在设置后使用 Mock<T>.VerifyAll() 来验证所有之前的设置是否已被调用(一次).
• You want to use Mock<T>.VerifyAll() after you setups to verify that all previous setups have been called (once).

var mock = new Mock<ICalculator>();
mock.Setup(m=>m.Sum(
  7, //value of 7
  3                //value of 3
));

mock.Setup(m=>m.Sum(
  5, //value of 5
  3                //value of 3
));

mock.VerifyAll();    

上面的代码验证 Sum 被调用了两次.一次使用 (7,3)，一次使用 (5,3).

The above code verifies that Sum is called twice. Once with (7,3) and once with (5,3).

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