How can I tell Moq to return a Task?

by

Your method doesn’t have any callbacks so there is no reason to use .CallBack(). You can simply return a Task with the desired values using .Returns() and Task.FromResult, e.g.:

MyType someValue=...;
mock.Setup(arg=>arg.DoSomethingAsync())        
    .Returns(Task.FromResult(someValue));

Update 2014-06-22

Moq 4.2 has two new extension methods to assist with this.

mock.Setup(arg=>arg.DoSomethingAsync())
    .ReturnsAsync(someValue);

mock.Setup(arg=>arg.DoSomethingAsync())        
    .ThrowsAsync(new InvalidOperationException());

Update 2016-05-05

As Seth Flowers mentions in the other answer, ReturnsAsync is only available for methods that return a Task<T>. For methods that return only a Task, 

.Returns(Task.FromResult(default(object)))

can be used.

As shown in this answer, in .NET 4.6 this is simplified to .Returns(Task.CompletedTask);, e.g.:

mock.Setup(arg=>arg.DoSomethingAsync())        
    .Returns(Task.CompletedTask);

More Related Contents:

  1. Mocking Extension Methods with Moq
  2. Mocking HttpClient in unit tests
  3. How to mock an async repository with Entity Framework Core
  4. Mocking Static Methods
  5. How to mock static methods in c# using MOQ framework?
  6. Mock static property with moq
  7. How to mock the new HttpClientFactory in .NET Core 2.1 using Moq
  8. Why am I getting an Exception with the message “Invalid setup on a non-virtual (overridable in VB) member…”?
  9. Using Moq to mock an asynchronous method for a unit test
  10. Is it possible to mock out a .NET HttpWebResponse?
  11. Using Moq to determine if a method is called
  12. Moq + Unit Testing – System.Reflection.TargetParameterCountException: Parameter count mismatch
  13. How to unit test with ILogger in ASP.NET Core
  14. How to mock ConfigurationManager.AppSettings with moq
  15. Mocking EF DbContext with Moq
  16. Why does the property I want to mock need to be virtual?
  17. How to test method call order with Moq
  18. Moq: unit testing a method relying on HttpContext
  19. Moq – Non-overridable members may not be used in setup / verification expressions
  20. How do I mock User.Identity.GetUserId()?
  21. How do I Moq a method that has an optional argument in its signature without explicitly specifying it or using an overload?
  22. How to mock Controller.User using moq
  23. Unit testing with EF Core and in memory database
  24. Using Moq to override virtual methods in the same class
  25. Mocking using Moq in c#
  26. How to (should I) mock DocumentClient for DocumentDb unit testing?
  27. How to write this EF Mock setup code as a reusable Generic Boilerplate?
  28. Multiple Parallel.ForEach loops in .Net
  29. How to put a task to sleep (or delay) in C# 4.0?
  30. Test method is inconclusive: Test wasn’t run. Error?

Leave a Comment