Fix logic in PRT tidy script.

Author: sangwinc

stack/questiontest.php

@@ -81,8 +81,10 @@ public function update_expected_testcase(array $prtrenames, array $notedata) {
             $oldanswernotes = $prtstate->__get('answernotes');
             // Expected answer notes are always a string, first element in the array.
             $note = $oldanswernotes[0];
-            foreach (stack_utils::decompose_rename_operation($notedata[$oldprtname]) as $onote => $nnote) {
-                $note = str_replace($onote, $nnote, $note);
+            if (array_key_exists($oldprtname, $notedata) && is_array($notedata[$oldprtname])) {
+                foreach (stack_utils::decompose_rename_operation($notedata[$oldprtname]) as $onote => $nnote) {
+                    $note = str_replace($onote, $nnote, $note);
+                }
             }
             $newanswernotes = [$note];
             $prtstate->answernotes = $newanswernotes;

tidyquestion.php

@@ -91,7 +91,6 @@
     redirect($returnurl);
 } else if ($data = $form->get_data()) {
     $qtype = question_bank::get_qtype('stack');
-    $testscases = $qtype->load_question_tests($question->id);
 
     $transaction = $DB->start_delegated_transaction();
 
@@ -104,6 +103,10 @@
         $qtype->rename_input($question->id, $from, $to);
     }
 
+    // Rename inputs before getting the test cases.  These test cases need the _new_ input names.
+    // Get the test cases before renaming the question parts.
+    $testscases = $qtype->load_question_tests($question->id);
+
     // Rename the PRT nodes.
     $noderenames = [];
     foreach ($question->prts as $oldprtname => $prt) {