Copy quesion tests when doing 'Make copy' (Issue #41).

If you edit a question and then click the Make copy button
at the bottom of the form, we now detect this, and copy any question
tests from the original question to the new questions.

Of course, if you have added or removed a PRT or input, you will need to
fix the tests, but that is try if you edit a question normally too.

questiontype.php

@@ -129,6 +129,7 @@ class qtype_stack extends question_type {
                 $input = new stdClass();
                 $input->questionid = $fromform->id;
                 $input->name       = $inputname;
+                $input->options    = '';
                 $input->id = $DB->insert_record('qtype_stack_inputs', $input);
             }
 
@@ -266,16 +267,26 @@ class qtype_stack extends question_type {
             }
         }
 
+        // This is a bit of a hack. If doing 'Make a copy' when saving the
+        // editing form, then detect that here, and try to copy the question
+        // tests from the original question.
+        if (!isset($fromform->testcases) && $fromform->makecopy) {
+            $oldquestionid = optional_param('id', 0, PARAM_INT);
+            if ($oldquestionid) {
+                $fromform->testcases = $this->load_question_tests($oldquestionid);
+            }
+        }
+
         if (isset($fromform->testcases)) {
             // If the data includes the defintion of the question tests that there
             // should be (i.e. when doing import) then replace the existing set
             // of tests with the new one.
             $this->save_question_tests($fromform->id, $fromform->testcases);
+        }
 
-        } else {
-            // Otherwise, make sure there is no garbage left in the database,
-            // for example if we delete a PRT, remove the expected values for
-            // that PRT while leaving the rest of the testcases alone.
+        // Irrespective of what else has happened, ensure there is no garbage
+        // in the database, for example if we delete a PRT, remove the expected
+        // values for that PRT while leaving the rest of the testcases alone.
         list($nametest, $params) = $DB->get_in_or_equal($inputnames, SQL_PARAMS_NAMED, 'input', false, null);
         $params['questionid'] = $fromform->id;
         $DB->delete_records_select('qtype_stack_qtest_inputs',
@@ -286,7 +297,6 @@ class qtype_stack extends question_type {
         $DB->delete_records_select('qtype_stack_qtest_expected',
                 'questionid = :questionid AND prtname ' . $nametest, $params);
     }
-    }
 
     public function get_question_options($question) {
         global $DB;