如何对具有不同参数类型的同一方法的 2 个连续调用进行单元测试

使用 C# .NetFrameWork 4.7, Moq 1.4

我正在测试一种进行 2 个接口调用的方法。接口方法接受 1 个参数，该参数也是一个接口。很难对此进行测试，Moq 会抛出铸造错误。

具有以下特征的 2 个连续调用：

InterfaceUnderTest.MethodUnderTest(IEnumerable<IParamInterface>)

完整的代码示例可以在 github 上找到：https : //github.com/JayZhang727/UnitTestingInterfaceParams

以下是基本结构：

导入的接口和实现我无法更改：

public interface IWorkInterface
{
    string DoWork(IEnumerable<IParamInterface> para);
}

public interface IParamInterface
{
    IParamDataInterface GetParamData();
}

public interface IParamDataInterface
{
    string Id { get; set; }
}

public class ParamClass<T> : IParamInterface where T : IParamDataInterface
{
    public T ParamData { get; set; }

    public ParamClass()
    {

    }

    public ParamClass(T para)
    {
        this.ParamData = para;
    }

    public IParamDataInterface GetParamData()
    {
        return ParamData;
    }
}

public class ParamClassA : IParamDataInterface
{
    public ParamClassA()
    {
        this.Id = "Id";
        this.ParamClassAVar = 123;
    }

    public string Id { get; set; }

    public int ParamClassAVar { get; set; }

}

public class ParamClassB : IParamDataInterface
{
    public ParamClassB()
    {
        this.Id = "Id";
        this.ParamClassBVar = "not 123";
    }

    public string Id { get; set; }

    public string ParamClassBVar { get; set; }

}

这是被测类：

public ClassUnderTest(IWorkInterface workInt)
{
    this.WorkClient = workInt;
}

public IWorkInterface WorkClient { get; set; }

public string MethodUnderTest()
{
    var result = string.Empty;

    //Class A is an implementation of IParamDataInterface
    var a = new ParamClassA();
    var theParamA = new ParamClass<ParamClassA>(a);
    var listA = new List<IParamInterface>();
    listA.Add(theParamA);

    result = WorkClient.DoWork(listA);

    //Class B is also an implementation of IParamDataInterface
    var b = new ParamClassB();
    var theParamB = new ParamClass<ParamClassB>(b);
    var listB = new List<IParamInterface>();
    listB.Add(theParamB);

    result = result + WorkClient.DoWork(listB);

    return result;
}

这是我尝试过的测试调用：

private Mock<IWorkInterface> mockClient;

[TestMethod()]
public void DoWorkTest()
{
    mockClient = new Mock<IWorkInterface>(MockBehavior.Strict);
    var target = new ClassUnderTest(mockClient.Object);

    var mockSquence = new MockSequence();

    mockClient.InSequence(mockSquence).Setup(ec => ec.DoWork(It.Is<List<IParamInterface>>(el => ((ParamClassA)((ParamClass<ParamClassA>)el[0]).GetParamData()).ParamClassAVar == 123))).Returns("123");

    mockClient.InSequence(mockSquence).Setup(ec => ec.DoWork(It.Is<List<IParamInterface>>(el => ((ParamClassB)((ParamClass<ParamClassB>)el[0]).GetParamData()).ParamClassBVar == "not 123"))).Returns("not 123");

    //act
    target.MethodUnderTest();


    //assert
    mockClient.VerifyAll();
}

我收到关于无法从 A 类转换到 B 类的错误：

Message: Test method ClassUnderTesting.UnitTests.ClassUnderTestingTests.DoWorkTest threw exception: 
System.InvalidCastException: Unable to cast object of type 'ClassUnderTesting.ParamClass`1[ClassUnderTesting.ParamClassA]' to type 'ClassUnderTesting.ParamClass`1[ClassUnderTesting.ParamClassB]'.

似乎最小起订量没有按顺序进行，出于某种原因，第二个设置胜过第一个设置，顺序似乎没有帮助。有谁知道我应该如何设置和测试这两个调用？