In Ruby on Rails, if all of the validation rules for a given model are being tested within that model’s spec (or unit tests), is it still considered necessary to write a Cucumber scenario for each validation?
Would it suffice to instead write two scenarios: One for when valid data is entered, and one for when invalid data is entered?
This is a good question, and the answer is: It depends.
You can think of Cucumber as a way of communicating between the product owner, developers and testers.
If you feel that having the validations in Cucumber adds to the shared understanding of what the product does, then keep them there.
One approach is to combine the validations into a scenario outline: