Telerik JustMock doesn't call expected arranged method

Question

I have a simple silverlight unit test which doesn't work as expected:

DataContext context = Mock.Create<DataContext>(Constructor.Mocked);

List<Resource> resources = new List<Resource>();

        Resource resource = new Resource
        {
            ContentType = "string",
            Data = Encoding.UTF8.GetBytes("Test")
        };


  Mock.Arrange(() => context.Resources.Add(resource)).DoInstead(() => resources.Add(resource));

 Mock.Arrange(() => context.Resources.SingleOrDefault()).Returns(resources.SingleOrDefault());


 context.Resources.Add(resource);

var loaded = context.Resources.SingleOrDefault();

The resource property is added correctly to the local resources (context.Resources.Add(resource)) list, however when I'm trying to read it back (context.Resources.SingleOrDefault()) nothing gets returned.

Answer 1

In order to return the updated value of resources.SingleOrDefault(), you will need to use lambda expression in the arrangement, like this:

Mock.Arrange(() => context.Resources.SingleOrDefault())
    .Returns(() => resources.SingleOrDefault());

Otherwise, when the context.Resources.SingleOrDefault() method is called, the mock will return null, which is the value of the resources.SingleOrDefault() call at the time of the arrangement.