I think why this test is failing is that we're wiring up subscribers **after** the "user" interacts with the command.

Also, making subsequent calls to  `command.CanExecuteObservable` will return null.

So the `CanExecuteObservable` is just a wrapper around the first `ctor` parameter you pass into the `ReactiveCommand.Create` factory method. 

Can you elaborate on what you're trying to achieve here, perhaps there's a better way to go about it?