This is a clear case of RTFM!
I wanted to make sure that a function will return null when given a null or empty string and what I ended up doing was something like this:
@ValueSource does not accept null values so I passed it indirectly!
I didn’t like it so after, finally, reading the JUnit5 documentation I learned that the library had me covered from the beginning by providing three annotations exactly for this use case:
@NullSource, @EmptySource and @NullOrEmptySource are meant to be used whenever we need to check the behavior of our code when given null or empty inputs.
So the test changes to: