Test pre-requisites Go to a Moodle 2.6.0 instance (or any prior to MDL-20154 ) Create a course in it and enrol teacher and student As a teacher: Create a new Question category A (from the question bank) Add two (true/false) questions to the new category A Create another Question category B Add one true/false question to it Create a new quiz 1 Add a 'Random question' to the quiz based on the category A Create a new quiz 2 Add the question from B As the student: Attempt and finish the quizzes As the teacher (in that order): Delete the quiz 1 Delete the questions in the question category A Delete the questions in the question category B Delete the quiz 2 Try deleting the category A, you'll be warned that some questions remain in that category, DO NOT proceed Try deleting the category B, you'll be warned that some questions remain in that category, DO NOT proceed Test steps Update to the version you're meant to test As the teacher, try to delete the question category A again Confirm that the category was deleted without any warning, or need for additional input from your part All the entries in mdl_question for category A should be gone Repeat for category B