How to await an async private method invoked using reflection in WinRT?

Question

I\'m writing unit tests for a WinRT app, and I am able to invoke non-async private methods using this:

TheObjectClass theObject = new TheObjectClass();
Type          


        

Answer 1

Invoke should return an object convertible to Task. Just await that.

If your private method returns void, then you'll need a custom SynchronizationContext, which is messy. It's better to have your methods return Task/Task<T>.

Answer 2

Well you need to use the value returned by the method. Do you know the type? For example, if it's always a Task, you could use:

await (Task) objType.GetTypeInfo()
                    .GetDeclaredMethod("ThePrivateMethod")
                    .Invoke(theObject, null);

If you don't know the return type but know it will be awaitable, you could use dynamic typing:

await (dynamic) objType.GetTypeInfo()
                       .GetDeclaredMethod("ThePrivateMethod")
                       .Invoke(theObject, null);

I would try to avoid having to call a private method by reflection in your unit tests in the first place though. Can you test it indirectly via the public (or internal) API? That's generally preferable.