public void NewClass_Created_NotAddedToList()
 {
     var domainEvent = new DomainObjectCreatedEvent<Classifier>(new Classifier("class"));
     var interfaceSelectionSource = 
         new InterfaceSelectionItemsSource(_classifiers, _query, _messageSystem);
     // act: let source react on add event
     interfaceSelectionSource.OnNewClassifierCreated(domainEvent);
     // assert: class should not be added
     Assert.IsEmpty(interfaceSelectionSource);
 }
 public void NewInterface_Created_AddedToList()
 {
     var domainEvent = new DomainObjectCreatedEvent<Classifier>(
         new Classifier("interface") {IsInterface = true});
     var interfaceSelectionSource =
         new InterfaceSelectionItemsSource(_classifiers, _query, _messageSystem);
     // act: let source react on add event
     interfaceSelectionSource.OnNewClassifierCreated(domainEvent);
     // assert: interface should be added
     Assert.IsTrue(interfaceSelectionSource.Count == 1);
 }