Mocking generic methods in Moq without specifying T

Question

I have an interface with a method as follows:

public interface IRepo
{
    IA Reserve();
}

I would like to mock the clas

Answer 1

Here's one way to do it which seems to work. If all the classes you're using in IRepo inherit from a single base class you can use this as-is and never have to update it.

public Mock SetupGenericReserve() where TBase : class
{
    var mock = new Mock();
    var types = GetDerivedTypes();
    var setupMethod = this.GetType().GetMethod("Setup");

    foreach (var type in types)
    {
        var genericMethod = setupMethod.MakeGenericMethod(type)
            .Invoke(null,new[] { mock });
    }

    return mock;
}

public void Setup(Mock mock) where TDerived : class
{
    // Make this return whatever you want. Can also return another mock
    mock.Setup(x => x.Reserve())
        .Returns(new IA());
}

public IEnumerable GetDerivedTypes() where T : class
{
    var types = new List();
    var myType = typeof(T);

    var assemblyTypes = myType.GetTypeInfo().Assembly.GetTypes();

    var applicableTypes = assemblyTypes
        .Where(x => x.GetTypeInfo().IsClass 
                && !x.GetTypeInfo().IsAbstract 
                 && x.GetTypeInfo().IsSubclassOf(myType));

    foreach (var type in applicableTypes)
    {
        types.Add(type);
    }

    return types;
}

Otherwise, if you don't have a base class you can modify the SetupGenericReserve to not use the TBase type parameter and instead just create a list of all the types you want to set up, something like this:

public IEnumerable Alternate()
{
    return new [] 
    {
        MyClassA.GetType(),
        MyClassB.GetType()
    }
}

Note: This is written for ASP.NET Core, but should work in other versions except for the GetDerivedTypes method.