如何获得模拟类内部调用的方法的结果

如何解决如何获得模拟类内部调用的方法的结果

有没有一种方法可以将方法返回的结果返回到模拟对象中？

例如，如果我具有以下类和接口：

DoSomethingClass.cs

public class DoSomethingClass
{
  
  IInternalClass _intClass;

  public DoSomethingClass(IInternalClass intClass)
  {
    _intClass = intClass;
  }
  
  void DoSomething(int number)
  {
    // do some transformation to the number,e.g.
    var transformednumber = number * (number - 1);
    
    var x = _intClass.IsEven(transformednumber);

    // do something else
  }
}

InternalClass.cs

public interface IInternalClass
{
  bool IsEven(int number);
}

public class InternalClass: IInternalClass
{
  
  public InternalClass();
  
  public bool IsEven(int number)
  {
    return number % 2 == 0;
  }
}

和一个测试班：

Tests.cs

public class Tests
{
  [Fact]
    public async Task test_something()
    {

        //PREPARE
        var request = 10

        var internalMock = new Mock<IInternalClass>();
        var classtoTest = new DoSomethingClass(internalMock.Object);

        // ACT

        await classtoTest.DoSomething(request);

        //ASSERT

        //Here I want to check if the method IsEven of the internal class return the right result
    }
  }
}

我要声明的是在主方法IsEven中调用的InternalClass的方法DoSomething的返回值，我无法知道{{1 }}在此方法内计算并传递给transformednumber。

注意：我使用IsEven库来模拟对象。

对不起上面的愚蠢示例，但我这里没有任何简单的真实代码显示，但是我希望这足以理解这个问题。

解决方法

我假设您要验证在模拟的IInternalClass上是否已调用IsEven方法？

如果是这种情况，则可以按以下方式在模拟中使用Verify方法：

[Fact]
public void DoSomething_Verify()
{
    var request = 10;
    var internalMock = new Mock<IInternalClass>();
    var classToTest = new DoSomethingClass(internalMock.Object);

    classToTest.DoSomething(request);

    //Verify that the mock is invoked with the expected value,the expected number of times
    internalMock.Verify(v => v.IsEven(90),Times.Once);
    //There are lots of other options for Times,e.g. it is never called with an unexpected value maybe.
    internalMock.Verify(v => v.IsEven(91),Times.Never);
}

还要在等待时调用DoSomething方法，您将需要如下更改方法签名：

public async Task DoSomethingAsync(int number)
{
    // do some transformation to the number,e.g.
    var transformedNumber = number * (number - 1);

    var x = _intClass.IsEven(transformedNumber);

    // do something else
}

然后您可以创建一个像这样的单元测试：

[Fact]
public async void DoSomething_VerifyAsync()
{
    var request = 10;
    var internalMock = new Mock<IInternalClass>();
    var classToTest = new DoSomethingClass(internalMock.Object);

    //To call the DoSomething method with await the method needs the async Task and a good convention is to append Async to the name
    await classToTest.DoSomethingAsync(request);

    //Another slightly more generic option is to verify that the mock was called with and int exactly n Times
    internalMock.Verify(v => v.IsEven(It.IsAny<int>()),Times.Exactly(1));
}