Mock.SetupStatic Exception: GenericArguments violates the constraint

[Livio]

Hi,

I'm experiencing the following problem.
I'm trying to mock this class:

public class UnmockableClass<T>
    {
        private bool _dummyvariable;

        public UnmockableClass()
        {
            _dummyvariable = true;
        }

        public static UnmockableClass<T> GetInstance<TDescriptor>() where TDescriptor : IDescriptor<T>
        {
           throw new NotImplementedException();
        }
    }

inside this test

[TestClass]
    public class UnmockableClassTest
    {
        [TestMethod]
        public void SimpleTest()
        {
            Mock.SetupStatic<UnmockableClass<AvailableID>>();
            //nothing else. The test will fail with just this line of code above

        }
    }

But the test fails and I obtain this exception:

Test 'JustMockIssueTestMock.UnmockableClassTest.SimpleTest' failed: Test method JustMockIssueTestMock.UnmockableClassTest.SimpleTest threw exception:
System.ArgumentException: GenericArguments[0], 'JustMockIssue.IDescriptor`1[T]', on 'JustMockIssue.UnmockableClass`1[JustMockIssue.AvailableID] GetInstance[TDescriptor]()' violates the constraint of type 'TDescriptor'. ---> System.Security.VerificationException: Method JustMockIssue.UnmockableClass`1[JustMockIssue.AvailableID].GetInstance: type argument 'JustMockIssue.IDescriptor`1[T]' violates the constraint of type parameter 'TDescriptor'.
    at System.RuntimeMethodHandle.GetStubIfNeeded(RuntimeMethodHandleInternal method, RuntimeType declaringType, RuntimeType[] methodInstantiation)
    at System.Reflection.RuntimeMethodInfo.MakeGenericMethod(Type[] methodInstantiation)
     --- End of inner exception stack trace ---
    at System.RuntimeType.ValidateGenericArguments(MemberInfo definition, RuntimeType[] genericArguments, Exception e)
    at System.Reflection.RuntimeMethodInfo.MakeGenericMethod(Type[] methodInstantiation)
    at Telerik.JustMock.Weaver.WeaverInterceptorBuilder.DefineInterceptor(MethodBase methodBase, FieldBuilder fldInterceptor, Type[] parameters)
    at Telerik.JustMock.Weaver.DynamicInjector.EmitInterceptor(ILGenerator il, MethodBase methodInfo)
    at Telerik.JustMock.Weaver.DynamicInjector.Inject(Type targetType, MethodBase methodBase, MethodInfo containerMethodInfo)
    at Telerik.JustMock.Weaver.DynamicInjector.Inject(Type targetType, MethodBase methodBase, MethodInfo injectingMethod, Boolean force)
    at Telerik.JustMock.Weaver.DynamicInjector.Inject(Type targetType, MethodBase methodBase)
    at Telerik.JustMock.MockManager.SetupMock(Behavior behavior, Boolean static)
    at Telerik.JustMock.MockManager.SetupStatic()
    at Telerik.JustMock.Mock.SetupStatic(Type targetType, Behavior behavior, StaticConstructor staticConstructor)
    at Telerik.JustMock.Mock.SetupStatic[T]()
    UnmockableClassTest.cs(17,0): at JustMockIssueTestMock.UnmockableClassTest.SimpleTest()

Do you have any idea why this happens? I wasn't able to find any help about this problem in the forum, except this one.

I'm working with JustMock Q2 2012 (trial version), VS2010 and Win7x64.
Thanks in advance
Livio

[Ricky]

Hi Livio,
Thanks again for reporting the issue. However, it is possible to write the test in the following way that fixes the problem:

var unmockable = new UnmockableClass<AvailableID>();

Mock.Arrange(() => UnmockableClass<AvailableID>.GetInstance<YourDescriptor>()).Returns(unmockable);

In addition, I got your exception for Mock.SetupStatic which is logged and hopefully will be fixed in the upcoming service pack. Here is the PITS task to follow:
http://www.telerik.com/support/pits.aspx#/public/justmock/12092 
 

Kind Regards
Ricky
the Telerik team

[Livio]

Hi Ricky,

thanks for your answer and your suggestion; however, I'm not able to apply to my case the workaround you suggested.
In my scenario, this UnmockableClass is doing some weird things in the constructor; I have omitted this to make the example easy to understand, but let's say that the UnmockableClass, in the constructor, is calling an unavailable web service.

At this point, I can't write

Mock.Arrange(() => UnmockableClass<AvailableID>.GetInstance<YourDescriptor>()).Returns(unmockable);

because this instruction will call the real UnmockableClass constructor, that is something I can't do.
So, for what I know, my only available option could be to mock the creation of the object, writing something like


Mock.Create<UnmockableClass<AvailableID>>(Constructor.Mocked)

to avoid real actions to be executed.

But this instruction above doesn't work too and throws a new exception related to some "interceptor":

 

Test method JustMockIssueTestMock.UnmockableClassTest.SimpleTest threw exception: 

System.ArgumentException: GenericArguments[0], 'JustMockIssue.IProtocolDescriptor', 
    on 'JustMockIssue.UnmockableClass`1[JustMockIssue.AvailableID] Intercept[TDescriptor](JustMockIssue.UnmockableClass`1[T], Boolean ByRef)'  violates the constraint of type 'TDescriptor'. ---> System.Security.VerificationException: Method UnmockableClass`1_Interceptor_55171d2dddaa4463b9b600d5130c4f3c[T].Intercept: type argument 'JustMockIssue.IProtocolDescriptor' violates the constraint of type parameter 'TDescriptor'.

Am I doing something wrong? Is there something else I can do to solve this issue?
Thanks in advance for your help.
Livio

[Ricky]

Hi Livio,

Thanks again for contacting us.

We have released  the Q2 2012 SP1 a few days back that solves your specific issue. Please check it  out and let us know if you still having the problem. 

Kind Regards
Ricky
the Telerik team