what is the formal name for success unit tests vs error unit tests?

What is the formal name for "success unit tests" vs "error unit tests"? In this context I'm refering to a success unit test to validate the primary success scenario and an error unit test to validate an error handling routine.

For creating a user, the success unit test would validate that the user was created successfully. One error unit test would validate that if the client did not provide a LastName value then the system should return an exception stating "Last Name is required."

So in the domain of unit testing is their a formal/proper name to describe these 2 different types of unit tests?