Question

I’m using the Composite Application Library‘s event aggregator, and would like to create a mock for the IEventAggregator interface, for use in my unit test.

I’m planning on using Moq for this task, and an example test so far looks something like this:

var mockEventAggregator = new Mock<IEventAggregator>(); var mockImportantEvent = new Mock<ImportantEvent>(); mockEventAggregator.Setup(e => e.GetEvent<SomeOtherEvent>()).Returns(new Mock<SomeOtherEvent>().Object); mockEventAggregator.Setup(e => e.GetEvent<SomeThirdEvent>()).Returns(new Mock<SomeThirdEvent>().Object); // ... mockEventAggregator.Setup(e => e.GetEvent<ImportantEvent>()).Returns(mockImportantEvent.Object);  mockImportantEvent.Setup(e => e.Publish(It.IsAny<ImportantEventArgs>()));  // ...Actual test...  mockImportantEvent.VerifyAll(); 

This works fine, but I would like know, if there is some clever way to avoid having to define an empty mock for every event-type my code might encounter (SomeOtherEvent, SomeThirdEvent, …)? I could of course define all my events this way in a [TestInitialize] method, but I would like to know if there is a more clever way? 🙂

Answer 1

I found the solution for this one:

var mockEventAggregator = new Mock<IEventAggregator>{ DefaultValue = DefaultValue.Mock }; 

will make the mockEventAggregator return mocks for all nested objects.