MDL-77913 qbank_previewquestion: deterministic ordering of versions.

Ensure the ordering of loaded question versions is consistent, avoids
random Oracle failures.

question/bank/previewquestion/classes/helper.php

@@ -311,7 +311,8 @@ class helper {
         $questionids = [];
         $sql = 'SELECT version, questionid
                   FROM {question_versions}
-                 WHERE questionbankentryid = ?';
+                 WHERE questionbankentryid = ?
+              ORDER BY version';
 
         $versions = $DB->get_records_sql($sql, [$questionbankentryid]);
         foreach ($versions as $key => $version) {

question/bank/previewquestion/tests/qbank_preview_helper_test.php

@@ -221,21 +221,28 @@ class qbank_preview_helper_test extends \advanced_testcase {
      * @covers ::load_versions
      */
     public function test_load_versions() {
-        global $DB;
         $this->resetAfterTest();
+
         $generator = $this->getDataGenerator()->get_plugin_generator('core_question');
         $qcat1 = $generator->create_question_category(['name' => 'My category', 'sortorder' => 1, 'idnumber' => 'myqcat']);
         $questiongenerated = $generator->create_question('description', null, ['name' => 'q1', 'category' => $qcat1->id]);
+
         $qtypeobj = question_bank::get_qtype($questiongenerated->qtype);
         $question = question_bank::load_question($questiongenerated->id);
         $versionids = helper::load_versions($question->questionbankentryid);
-        $this->assertCount(1, $versionids);
+        $this->assertEquals([
+            $question->id => 1,
+        ], $versionids);
+
         $fromform = new stdClass();
         $fromform->name = 'Name edited';
         $fromform->category = $qcat1->id;
-        $qtypeobj->save_question($questiongenerated, $fromform);
+        $questiontwo = $qtypeobj->save_question($questiongenerated, $fromform);
         $versionids = helper::load_versions($question->questionbankentryid);
-        $this->assertCount(2, $versionids);
+        $this->assertSame([
+            $question->id => 1,
+            $questiontwo->id => 2,
+        ], $versionids);
     }
 
     /**