Now you decide to add another feature: characters can cast spells on one another. The details of spells aren’t important for studying extensibility, so for now we will add a spellCast method to each character that returns the same character for everyone other than Frogs; for Frogs, the spellCast method should invoke the frog’s kiss method.
Write test cases to confirm that you can cast spells and that the characters resulting from spells retain all their original behavior.
Articulate how you decided what to test on the last question. Did you test that a prince who results from kissing a frog can have spells cast upon him? If not, extend your description of what tests to run and add a test case for this.
Explain the results of the casting-spell-on-kissed-frog test. Be precise: what caused the problem?
Release software (ie, add a new dashed line). Proceed to part 4.