GH-779 Fix application of json values from template

 1. Coding style fixes.
 2. Remove only fields that really have to be removed.
 3. Preparation of editor field takes place only if we have all required
    data.

classes/testenvironment.php

@@ -271,18 +271,9 @@ public function apply_jsonsaved_values(array &$formdefaultvalues) {
             ];
         }
 
-        $updatescales = $formdefaultvalues['catquiz_catscales'] ?? null != $jsonobject['catquiz_catscales'];
-        if ($updatescales) {
+        if (($formdefaultvalues['triggered_button'] ?? null) === "reloadTestForm") {
             $clearfields = [
                 'catquiz_subscalecheckbox_',
-                'feedback_scaleid_limit_',
-                'feedbackeditor_scaleid_',
-                'enrolment_message_checkbox_',
-                'catquiz_courses_',
-                'catquiz_group_',
-                'feedbacklegend_scaleid_',
-                'wb_colourpicker_',
-                'catquiz_scalereportcheckbox_',
             ];
             foreach ($formdefaultvalues as $key => $val) {
                 foreach ($clearfields as $field) {
@@ -296,7 +287,8 @@ public function apply_jsonsaved_values(array &$formdefaultvalues) {
         foreach ($jsonobject as $key => $value) {
 
             // Never overwrite a few values.
-            if (in_array($key, [
+            if (
+                in_array($key, [
                 'id',
                 'instance',
                 'name',
@@ -322,8 +314,8 @@ public function apply_jsonsaved_values(array &$formdefaultvalues) {
                 'conditionfieldgroup',
                 'downloadcontent',
                 'timemodified',
-
-                ])) {
+                ])
+            ) {
                 continue;
             }
             if (preg_match('/^feedbackeditor_scaleid_(\d+)_(\d+)$/', $key, $matches)) {
@@ -340,7 +332,7 @@ public function apply_jsonsaved_values(array &$formdefaultvalues) {
                 $scaleid = intval($matches[1]);
                 $rangeid = intval($matches[2]);
                 $filearea = sprintf('feedback_files_%d_%d', $scaleid, $rangeid);
-                $jsonobject[$key.'format'] = 1;
+                $jsonobject[$key . 'format'] = 1;
                 $field = sprintf('feedbackeditor_scaleid_%d_%d', $scaleid, $rangeid);
                 if ($options) {
                     $data = (object) file_prepare_standard_editor(
@@ -352,19 +344,19 @@ public function apply_jsonsaved_values(array &$formdefaultvalues) {
                         $filearea,
                         intval($this->componentid)
                     );
+                    $formdefaultvalues[$key] = $data->$key;
+                    $formdefaultvalues[$key . '_editor'] = $data->{$key . '_editor'};
+                    $formdefaultvalues[$key . 'format'] = $data->{$key . 'format'};
+                    $draftitemid = file_get_submitted_draft_itemid($field);
+                    file_prepare_draft_area(
+                        $draftitemid,
+                        $context->id,
+                        'local_catquiz',
+                        $filearea,
+                        intval($this->componentid)
+                    );
+                    continue;
                 }
-                $formdefaultvalues[$key] = $data->$key;
-                $formdefaultvalues[$key.'_editor'] = $data->{$key.'_editor'};
-                $formdefaultvalues[$key.'format'] = $data->{$key.'format'};
-                $draftitemid = file_get_submitted_draft_itemid($field);
-                file_prepare_draft_area(
-                    $draftitemid,
-                    $context->id,
-                    'local_catquiz',
-                    $filearea,
-                    intval($this->componentid)
-                );
-                continue;
             }
 
             $formdefaultvalues[$key] = $value;