OccursNever/OccursOnce not working properly

[Javier]

Hi, I would like to test this static method:

public static class UnitOfWorkExtensions
{

        public static void SetSubCategory(this IOperationTracer tracer, string subCategory)
        {
            UnitOfWork unitOfWork = UnitOfWork.Current;
            if (unitOfWork != null && unitOfWork.CorrelationId != null)
            {
                tracer.SetSubCategory(UnitOfWork.Current.CorrelationId, subCategory);
            }
        }
}
I am implementing the test like this:
[TestMethod]
      public void SetSubCategoryTest()
      {
          Mock.SetupStatic(typeof(UnitOfWorkExtensions));
          IOperationTracer operationTracer = Mock.Create<OperationTracer>();


          Mock.Arrange(() => operationTracer.SetSubCategory(null, "subCategory")).DoNothing().OccursNever();

          UnitOfWorkExtensions.SetSubCategory(operationTracer, "subCategory");
          Mock.Assert(operationTracer);

          UnitOfWork.Current = new UnitOfWork();
          UnitOfWork.Current.CorrelationId = "11111";

          Mock.Arrange(() => operationTracer.SetSubCategory(null, "subCategory")).DoNothing().OccursOnce();

          UnitOfWorkExtensions.SetSubCategory(operationTracer, "subCategory");
          Mock.Assert(operationTracer);

      }
The test is failing and I don't have a clue why

[Kaloyan]

Hi Javier,

Thank you for contacting Telerik support.

I managed to reproduce the issue. Debugging it, I noticed two things that might have caused it.

1. To test the UnitOfWorkExtensions class, you don`t need to mock it in your current test method. However, if for any reason you will need this, you should specify the mock behavior to CallOriginal, like this:
   

   Mock.SetupStatic(typeof(UnitOfWorkExtensions), Behavior.CallOriginal);

   This will tell the UnitOfWorkExtensions class to call the original logic if there aren`t any further arrangements. Note that, in the refactored test below, I have completely dropped the mocking of this class.
2. After you have specified the UnitOfWork.Current and its CorrelationId to "11111", you should expect a call to SetSubCategory with CorrelationId equals to "11111", instead of null. This is the main reason for the failing test. I wrote it like this and it behaves as expected:
   
   [TestMethod]

   public void SetSubCategoryTest()

   {

       IOperationTracer operationTracer = Mock.Create<OperationTracer>();

    

    

       Mock.Arrange(() => operationTracer.SetSubCategory(null, "subCategory")).DoNothing().OccursNever();

    

       UnitOfWorkExtensions.SetSubCategory(operationTracer, "subCategory");

       Mock.Assert(operationTracer);

    

       UnitOfWork.Current = new UnitOfWork();

       UnitOfWork.Current.CorrelationId = "11111";

    

       Mock.Arrange(() => operationTracer.SetSubCategory("11111", "subCategory")).DoNothing().OccursOnce();

    

       UnitOfWorkExtensions.SetSubCategory(operationTracer, "subCategory");

       Mock.Assert(operationTracer);

   Kaloyan