With the addition of the async/await keywords in .NET Framework 4.5, many more methods will now return Task<TResult>. For example, a web service method can now be created to return Task<TResult> so it is ready for the async/await keywords. This brings up the question on how you can unit test these methods.
Read more: http://www.intertech.com/Blog/creating-a-task-with-a-known-result/#ixzz3xSNIAWB7