Enough with the horrific misquotes - this is about Moq and async (that's my slight justification for robbing Herman Melville).
It's pretty straightforward to use Moq to do async testing thanks to it's marvellous
ReturnsAsync method. That means it's really easy to test a class that consumes an async API. Below is an example of a class that does just that: (it so happens that this class is a Web API controller but that's pretty irrelevant to be honest)
To mock the
_sageService.DeleteAsync method it's as easy as this:
Nope, I'm not getting into metaphysics. Something more simple. What if the
async API you're consuming returns just a
Task? Not a
int but a simple old humble
So to take our example we're going from this:
Your initial thought might be "well that's okay, I'll just lop off the
ReturnsAsync statements and I'm home free". That's what I thought anyway.... And I was *WRONG*! A moments thought and you realise that there's still a return type - it's just
Task now. What you want to do is something like this:
No it won't -
void is not a real type and much as you might like it to, this is not going to work.
So right now you're thinking, well Moq probably has my back - it'll have something like
ReturnsTask, right? Wrong! It's intentional it turns out - there's a discussion on GitHub about the issue. And in that discussion there's just what we need. We can use
Task.FromResult alongside Moq's good old
Returns method and we're home free!