mod/quiz/tests/attempt_walkthrough_from_csv_test.php

Contains \mod_quiz\attempt_walkthrough_from_csv_test

It is extended by:

• \quiz_statistics\stats_from_steps_walkthrough_test
• \quiz_responses\responses_from_steps_walkthrough_test

But it is not, itself, a testcase.

Past experience has shown that it's not a good idea to extend non-abstract test classes. When this has been encountered in the past we've discovered situations where tests have been added for a specific thing, but are then applied to every instance that extends without testing the child target.

We should:

• declare \mod_quiz\attempt_walkthrough_from_csv_test as abstract
• extend it for mod_quiz
• write a phpcs sniff to make all non-abstract tests final