c# - How to Mock NamespaceManager Class Methods Using Moq?

Question

https://docs.microsoft.com/en-us/dotnet/api/microsoft.servicebus.namespacemanager?redirectedfrom=MSDN#microsoft_servicebus_namespacemanager

I want to mock CreateTopicAsync method. But because of the sealed nature of the class i am not able to mock the class. Any one Knows?

Answer 1

You can't mock a sealed class. Mocking relies on inheritence to build on the fly copies of the data. So trying to mock a sealed class is impossible.

So what do I do?

What you can do is write a wrapper:

public class NamespaceManagerWrapper : INamespaceManagerWrapper 
{
   private NamespaceManager _instance;

   public NamespaceManagerWrapper(NamespaceManager instance)
   {
      _instance = instance;
   }

   public ConsumerGroupDescription CreateConsumerGroup(ConsumerGroupDescription description)
   {
       return _instace.CreateConsumerGroup(description);
   }

   etc....
}

interface for the mock

public interface INamespaceManagerWrapper
{
   ConsumerGroupDescription CreateConsumerGroup(ConsumerGroupDescription description);
   ....etc.
}

your method should now accept your wrapper interface on the original object:

public void myMethod(INamespaceManagerWrapper mockableObj)
{
   ...
   mockableObj.CreateConsumerGroup(description);
   ...
}

Now you can mock the interface:

Mock<INamespaceManagerWrapper> namespaceManager = new Mock<INamespaceManagerWrapper>();
....etc.

myObj.myMethod(namespaceManager.Object);

Unfortunatly that's the best you can do. It's a siliar implementation to HttpContextWrapper