The unit tests are already sufficient, I think, but best to test through the UI too. Create a quiz in a new course. Add one Cloze question to the question bank (There is one you can copy and paste in the docs https://docs.moodle.org/29/en/Embedded_Answers_(Cloze)_question_type#Examples ) Add one random question to the quiz, picking from the category where you added the Cloze question. Preview the quiz a few times, and verify that each time you get the whole cloze question, not something weird. Go back to the Edit quiz page. Add the Cloze question directly to the quiz. Go to the question bank and 'delete' the question. Go back to the edit quiz page, and remove the Cloze question from the quiz, but leave the random question there. Now try to preview the quiz, and verify that you get an error telling you that there are not enough questions in that category. (Steps 6-8 may seem weird, but what is going on is that if you try to delete a question that is in use, then it is not really deleted, it is just marked hidden. We want to test this, so we make the question used by adding it to the quiz, then delete it, then remove it from the quiz again to get back to the state we want to test.)