rails/journey — comment on commit 70d101b3386ba26ff801cec496da9c23389434aa
File:  line 0
By cgunther:

@Dinuz are the models you're passing to the URL helper persisted, or are they unsaved objects?

That was the root of my error, I was passing unsaved models in my tests to the URL helpers, which when `#to_param` is called on them, returned `nil`.