1. So we will truncate the question summary to 65000 chars if necessary.
2. Also, fix one minor error in mutlianswer save_question_options.
question_bank::MAX_SUMMARY_LENGTH is not the most logical class to add
the constant to, but it needs to be accessible during upgrade, so I was
lazy and put it there.
This commit also includes a lot of useful tidying up of some of the unit
test helper code. I turned out that I could not use all the helper code
in my new tests, but despite that it will be useful in the future, so I
am committing it here.
It is effectively impossible to compute the right random guess score, so we should not compute anything, rather than computing a number that we know is wrong.
This patch also fixes a multianswer unit test error that was shown up by this fix.
Probably easiest to explain by example: If the right answer is 1.23 m with alternate
unit 100 cm = 1m then the completely right answers are 1.23 m and 123 cm.
Right answer, wrong unit responses include 1.23, 1.23 frogs and 1.23 cm.
123 m is not considered to have the correct numerical value.
We may well re-consider the way this works in a future version of Moodle.
Unit grading was not implemented before Moodle 2.0. In Moodle 2.0, the unit grading
was more permissive than here, for example 123 m would have been graded correctly in
2.0. However, I'm not sure I follow the rationale for that.
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.
The main problem lack of this was causing is if you click through a quiz without answering any questions, mulitanswer questions would get marked as answered.
Tim Hunt