I'm having trouble testing reactive code that's consuming a Task based service. In my class under test I consume the task and use ToObservable to do reactive-y things with it.
public void Method()
{
_svc.MyTaskServiceMethod().ToObservable().Select(....) //pipe it elsewhere and do interesting things.
}
Now in a unit test I'm testing some timing (using Moq for the service)
svcMock.Setup(x => x.MyTaskServiceMethod()).Returns(() =>
Observable.Return("VALUE", testScheduler)
.Delay(TimeSpan.FromMilliseconds(100), testScheduler)
.ToTask()
);
The problem is that despite using the test scheduler in the Return/Delay calls, the task itself is still completing on a separate thread. I'm seeing this by adding a couple of Console writes of the current managed thread id to the code.
svcMock.Setup(x => x.MyServiceMethod()).Returns(() =>
{
var task = Observable.Return("VALUE", testScheduler)
.Delay(TimeSpan.FromMilliseconds(1000), testScheduler)
.Do(x => { Console.WriteLine(Thread.CurrentThread.ManagedThreadId.ToString() + " Obs"); })
.ToTask();
task.ContinueWith((_) =>
{
Console.WriteLine(Thread.CurrentThread.ManagedThreadId.ToString() + " Task");
});
return task;
});
The Do(..) executes on the primary testing thread, and happens exactly when I expect after a testSchduler.AdvanceBy(..) call.
The task continuation is still happening in a separate thread and basically doesn't execute until after the body of the unit test has finished. So in the body of my target, nothing ever really gets pushed through my task.ToObservable() observable.
