The sequence of questions that made up a quiz used to be stored as a
comma-separated list in quiz.questions. Now the same information is
stored in the rows in the quiz_slots table. This is not just 'better' in
a database design sense, but it allows for the future changes we will
need as we enhance the quiz in the MDL-40987 epic.
Having changed the database structure, all the rest of the code needs to
be changed to account for it, and that is done here.
Note that there are not many unit tests for the changed bit. That is
because as part of MDL-40987 we will be changing the code further, and
we will add unit tests then.
This data should all have been upgraded when moving to Moodle 2.1. It
was only kept as a back-up, and now, after 3 years have past, we can
clean it up.
This parallels question_attempt->minfraction, which allows the
fractional mark to go below zere.
This is needed to allow the certainty-base marking behaviours to work
better.
1/ type/match/tests/walkthrough_test.php - tests are failing randomly, looks like some weird randomisation is going on there - see TODOs
2/ type/multianswer/tests/upgradelibnewqe_test.php contains invalid expected value - see TODO
There was one place where I had only fixed the backup code to work-around bad data from Moodle 2.0. I needed to make the equivalent change in the upgrade code.
The bad data is that the seq_number fields can be wrong (not unique). Se already have data ordered by (seq_number, id) and the array keys of the array we are building are not used for anything, so this fix deals with the problem.
There were two main problems:
1. The unit tests for upgrading adaptive quiz attempts had slighly the
wrong $expectedqa, and so matching that the upgrade was doing the wrong
thing in certain situations. The main issue was that it was setting
-_try = 1 on the first step, which broke the penalty calculation when
the quiz was regraded. There were also some other subtleties with
incrementing -_try that were not right before.
2. It was possible in 2.0 and earlier for two question_states to get the
same seq_number, and restoring 2.0 backups was rashly assuming that that
was unique.