[SOLVED] How to test a view with a named slot?

Did you ever get this fixed? I am hitting the same problem - cannot test a view containing a slot.

Error: Unhandled promise rejection: Error invoking SlotCustomAttribute. Check the inner error for details.
	------------------------------------------------
	Inner Error:
	Message: key/value cannot be null or undefined. Are you trying to inject/register something that doesn't exist with DI?
	Inner Error Stack:
	Error: key/value cannot be null or undefined. Are you trying to inject/register something that doesn't exist with DI?