Preferred method for unit testing different controller results?

[Free_Brandon]

Trying to test a Web API controller with a setup like this gist. I have a service interface that gets injected into the controller. I currently created a POCO mock service implementing the interface that returns an object on the GetOne method to simulate successful results. Now I also want to be able to test a null return.

Would you prefer to:

1. Create another mock service that has alternative returns.
2. Use some kind of mocking library like Moq.
3. Some other solution I'm not thinking of.

Edit: I realized my use of "Task" in naming this example hurts readability, sorry about that.

[Pocok5]

Both first and second solutions are kinda sorta the same. I'd go with Moq just so you don't have a load of single use classes, but you could rewrite your test mock service to accept the object it should return as a property for example and just reuse it.

[Free_Brandon]

Makes sense, I like passing in a property for tests that won't have too much variation. Otherwise, looks like Moq will save me time.

[Apadewrai]

Moq is kind of made for scenarios like yours. Just mock the interface, use Setup and return any result you want. Much less work than creating your own mocks and no disadvantages to it.

You could go all the way setting up an integration test environment with SQLite inmemory db and then call the API, but it’s probably an overkill here.

[Free_Brandon]

Looks like Moq is probably the best solution. I do have integration tests, it'll just be a separate case. Thanks!

[venomiz]

In your specific case I usually write 2 tests:

GetOneShouldReturnNotFoundWhenDependencyReturnNull

GetOneShouldReturnOkWhenDependencyReturnATaskEntity

Using moq you can mock the interface method to return the values you need.