I'm getting this argument exception: System.ArgumentException : The type or method has 3 generic parameter(s), but 2 generic argument(s) were provided. A generic argument must be provided for each generic parameter. at System.RuntimeType.SanityCheckGenericArguments(RuntimeType[] genericArguments, RuntimeType[] genericParamters) at System.Reflection.RuntimeMethodInfo.MakeGenericMethod(Type[] methodInstantiation) at ..(Type , MethodBase , BindingFlags ) at ..(Type , MethodBase ) at ..Create(Object , MethodInfo , Boolean ) at ..( ) at ..(Expression`1 ) at Telerik.JustMock.Mock..( ) at ..[,]( , Func`2 ) at Telerik.JustMock.Mock.Arrange[TResult](Expression`1 expression) Heres an example of a failing test: [Test] public void GenericTestCanMockTwoGenericMethods() { var mocked = Mock.Create<GenericTest>(); IEnumerable<EVENT_CODE> n = null; Mock.Arrange(() => mocked.Query<EVENT_CODE, ALARM_CODE>(Arg.AnyString, Arg.IsAny<object>())).Returns(n).MustBeCalled(); } public interface GenericTest { IEnumerable<T1> Query<T1, T2>(string arg1, params object[] args); IEnumerable<T1> Query<T1, T2, T3>(string arg1, params object[] args); }