C# Nunit Moq 无法通过测试

Question

I have this class:

class MyClass
{
    private ISomeInterface blabla;

    public MyClass() : this(new SomeInterfaceImplementation()) {}

    internal MyClass(ISomeInterface blabla)
    {
        this.blabla = blabla;
    }

    public void SomeMethod(string id, int value1, int value2)
    {
        this.blabla.DoSomethingWith(id, new ValueClass(value1, value2))
    }
}

I also have this test:

[TestFixture]
public class MyClassTest
{
    private const string ID = "id";
    private const int VALUE1 = 1;
    private const int VALUE2 = 2;

    private ValueClass valueClass;

    private Mock<ISomeInterface> mockInterface;

    private MyClass myClass;

    [SetUp]
    public void SetUp()
    {
        this.valueClass = new ValueClass(VALUE1, VALUE2);
        this.mockInterface = new Mock<ISomeInterface>();
        this.myClass = new MyClass(this.mockInterface.Object);
    }

    [Test]
    public void GIVEN_AnID_AND_AValue1_AND_AValue2_WHEN_DoingSomeMethod_THEN_TheSomeInterfaceShouldDoSomething()
    {
        this.myClass.SomeMethod(ID, VALUE1, VALUE2);
        this.mockInterface.Verify(m => m.DoSomethingWith(ID, this.valueClass), Times.Once()); //<- Test fails here!
    }
}

I don't know why but I can't get this test to pass. NCrunch is giving me the following error message:

Moq.MockException : Expected invocation on the mock once, but was 0 times: m => m.DoSomethingWith("ID", .valueClass) No setups configured.

Performed invocations:

ISomeInterface.DoSomethingWith("ID", MyNamespace.ValueClass) at Moq.Mock.ThrowVerifyException(MethodCall expected, IEnumerable 1 setups, IEnumerable 1 actualCalls, Expression expression, Times times, Int32 callCount) at Moq.Mock.VerifyCalls(Interceptor targetInterceptor, MethodCall expected, Expression expression, Times times) at Moq.Mock.Verify[T](Mock 1 mock, Expression 1 expression, Times times, String failMessage) at Moq.Mock 1.Verify(Expression 1 expression, Times times) at Tests.MyClassTest.GIVEN_AnID_AND_AValue1_AND_AValue2_WHEN_DoingSomeMethod_THEN_TheSomeInterfaceShouldDoSomething() in C:\\MySourceCode\\File and line number here.

As you can see, it seems like Moq is "not seeing" my invocation, probably because of the new ValueClass(value1, value2) how can I make this test pass or how can I change my design so it is easier to test? Where should I put the new ValueClass(value1, value2) ?

EDIT:

Is this a question I should ask on Software Engineering instead of StackOverflow? Is this out of scope?

Answer 1

Your problem is not matching argument in method call: this.valueClass by default is not equal to new ValueClass(value1, value2) because it will be two different instances of ValueClass . And by default two instances will be compared by references, which are different. You can:

• Override Equals and GetHashCode methods in ValueClass to change the way how two instances compared. Ie compare by values instead of comparing by references.
• Ignore this argument with It.Any<ValueClass>() . It's good if you don't care about specific values of ValueClass and just want to check method was called. Not always best option
• Use predicate to check values of ValueClass manually: It.Is<ValueClass>(vc => vc.Value1 == VALUE1 && vc.Value2 == VALUE2) . Sometimes it's also good. Eg if you cannot override Equals . But it makes tests much less readable.