This test requires a question category containing some questions, and one category (X) that contains exactly 4 questions.
1. Login as a teacher and add a quiz activity. Make sure Question order is As shown on the edit screen.
2. Go to the edit quiz page, and if necessary switch to the Edit quiz tab. Make sure the question bank is visible.
3. Select Category X in the question bank. Click the << icon to add one question to the quiz (non-randomly).
4. Now use the controls at the bottom of the question bank to Add 2 random questions to the quiz.
5. Click the Add a random question... button. Choose to add a random question from a different existing category that contains questions.
6. Click the Add a random question... button again. Choose to add a Random question using a new category.
7. The edit screen will tell you that the category is empty. Click the Show category contents link, then add one question to that category in the question bank.
8. Preview this updated quiz a few times and ensure that the non-random question is always the same; the random questions for Category X are random, but do not duplicate the non-random question; and the random question from the category with just one question in is not random.