How to build unit tests for ContinueWith

Question

a have this code:

var response = await await _service.GetProfile(code)
                                   .ContinueWith(async task =>{
   if(task.IsFaulted)
   {
      ///... anyway
     return object;
   }
});

I can't get to IsFault in my unit test. Can you help me build this unit test? I'm using Xunit and NSubstitute

Answer 1

Don't use ContinueWith . Just use await . A faulted Task will throw an exception on await that you can catch and handle.

try 
{
  var response = await _service.GetProfile(code);
  
  // Here Task is complete without an exception
}  
catch(Exception ex) 
{
   // Task has faulted
   return object;
}

Note that your test method has to be marked async .

---

In order to write unit tests for asynchronous code without using await, use synchronization objects like a ManualResetEvent .

See my answer here: "Thread was being aborted." in test that tests code that fires a delegate on a background thread