From 261abe282b3e0bc0ce4b518776a05f4523082b65 Mon Sep 17 00:00:00 2001
From: Philipp Imhof <52650214+PhilippImhof@users.noreply.github.com>
Date: Wed, 12 Mar 2025 07:41:42 +0100
Subject: [PATCH 1/5] add unit test for backup and restore (#166)

---
 tests/backup_restore_test.php | 195 +++++++++++++++++
 tests/behat/export.feature    |   2 +-
 tests/behat/mobile.feature    |   2 +-
 tests/behat/quiz.feature      |   2 +-
 tests/helper.php              | 397 +++++++++++++++++++++-------------
 5 files changed, 449 insertions(+), 149 deletions(-)
 create mode 100644 tests/backup_restore_test.php

diff --git a/tests/backup_restore_test.php b/tests/backup_restore_test.php
new file mode 100644
index 00000000..c27af3cf
--- /dev/null
+++ b/tests/backup_restore_test.php
@@ -0,0 +1,195 @@
+<?php
+// This file is part of Moodle - https://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <https://www.gnu.org/licenses/>.
+
+/**
+ * Unit tests for backup and restore.
+ *
+ * @package    qtype_formulas
+ * @copyright  2025 Philipp Imhof
+ * @license    https://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+namespace qtype_formulas;
+
+use backup;
+use backup_controller;
+use context_course;
+use core_question_generator;
+use qtype_formulas;
+use qtype_formulas_question;
+use restore_controller;
+use test_question_maker;
+
+defined('MOODLE_INTERNAL') || die();
+
+global $CFG;
+require_once($CFG->dirroot . '/backup/util/includes/backup_includes.php');
+require_once($CFG->dirroot . '/backup/util/includes/restore_includes.php');
+require_once($CFG->dirroot . '/mod/quiz/locallib.php');
+require_once($CFG->dirroot . '/mod/quiz/tests/quiz_question_helper_test_trait.php');
+require_once($CFG->dirroot . '/question/engine/tests/helpers.php');
+require_once($CFG->dirroot . '/question/type/formulas/questiontype.php');
+require_once($CFG->dirroot . '/question/type/formulas/tests/helper.php');
+
+/**
+ * Unit tests for backup and restore.
+ *
+ * @copyright  2025 Philipp Imhof
+ * @license    https://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ *
+ * @covers     \restore_qtype_formulas_plugin
+ * @covers     \backup_qtype_formulas_plugin
+ * @covers     \qtype_formulas
+ * @covers     \qtype_formulas_question
+ * @covers     \qtype_formulas_part
+ */
+final class backup_restore_test extends \advanced_testcase {
+    use \quiz_question_helper_test_trait;
+
+    /**
+     * Create a question object of a certain type, as defined in the helper.php file.
+     *
+     * @return qtype_formulas_question
+     */
+    protected function get_test_formulas_question($which = null) {
+        return test_question_maker::make_question('formulas', $which);
+    }
+
+    /**
+     * Data provider.
+     *
+     * @return array
+     */
+    public static function provide_question_names(): array {
+        return [
+            ['testsinglenum'],
+            ['testsinglenumunit'],
+            ['testsinglenumunitsep'],
+            ['testtwonums'],
+            ['testthreeparts'],
+            ['test4'],
+            ['testmethodsinparts'],
+            ['testalgebraic'],
+        ];
+    }
+
+    /**
+     * Backup and restore a question and check whether the data matches.
+     *
+     * @param string $questionname name of the test question (e. g. testsinglenum)
+     * @dataProvider provide_question_names
+     */
+    public function test_backup_and_restore(string $questionname): void {
+        global $USER, $DB;
+
+        // Login as admin user.
+        $this->resetAfterTest(true);
+        $this->setAdminUser();
+
+        // Create a course and a quiz with a Formulas question.
+        $generator = $this->getDataGenerator();
+        /** @var \core_question_generator $questiongenerator */
+        $questiongenerator = $this->getDataGenerator()->get_plugin_generator('core_question');
+        $course = $generator->create_course();
+        $context = context_course::instance($course->id);
+        $cat = $questiongenerator->create_question_category(['contextid' => $context->id]);
+        $question = $questiongenerator->create_question('formulas', $questionname, ['category' => $cat->id]);
+        quiz_add_quiz_question($question->id, $this->create_test_quiz($course));
+
+        // Backup course. By using MODE_IMPORT, we avoid the backup being zipped.
+        $bc = new backup_controller(
+            backup::TYPE_1COURSE, $course->id, backup::FORMAT_MOODLE, backup::INTERACTIVE_NO, backup::MODE_IMPORT, $USER->id
+        );
+        $backupid = $bc->get_backupid();
+        $bc->execute_plan();
+        $bc->destroy();
+
+        // Delete the current course to make sure there is no data.
+        delete_course($course, false);
+
+        // Create a new course and restore the backup.
+        $newcourse = $generator->create_course();
+        $context = context_course::instance($newcourse->id);
+        $rc = new restore_controller(
+            $backupid, $newcourse->id, backup::INTERACTIVE_NO, backup::MODE_IMPORT, $USER->id, backup::TARGET_NEW_COURSE
+        );
+        $rc->execute_precheck();
+        $rc->execute_plan();
+        $rc->destroy();
+
+        // Fetch the quiz and question ID.
+        $modules = get_fast_modinfo($newcourse->id)->get_instances_of('quiz');
+        $quiz = reset($modules);
+        $structure = \mod_quiz\question\bank\qbank_helper::get_question_structure($quiz->instance, $quiz->context);
+        $question = reset($structure);
+
+        // Fetch the question and its additional data (random vars, global vars, parts) from the DB.
+        $questionrecord = $DB->get_record('question', ['id' => $question->questionid], '*', MUST_EXIST);
+        $qtype = new qtype_formulas();
+        $qtype->get_question_options($questionrecord);
+
+        // Fetch the reference data for the given question.
+        $referencedata = test_question_maker::make_question('formulas', $questionname);
+
+        // First, we check the data for the main question, i. e. basic fields plus custom data for the
+        // Formulas question like varsrandom or varsglobal.
+        $basicfields = [
+            'name',
+            'questiontext',
+            'questiontextformat',
+            'generalfeedback',
+            'generalfeedbackformat',
+            'defaultmark',
+            'penalty',
+        ];
+        $questionfields = $basicfields + array_slice($qtype->extra_question_fields(), 1);
+        foreach ($questionfields as $field) {
+            self::assertEquals($referencedata->$field, $questionrecord->$field, $field);
+        }
+
+        // Next, we check the fields for each part.
+        $partfields = qtype_formulas::PART_BASIC_FIELDS + ['subqtext', 'subqtextformat', 'feedback', 'feedbackformat'];
+        foreach ($partfields as $field) {
+            foreach ($questionrecord->options->answers as $i => $part) {
+                self::assertEquals($referencedata->parts[$i]->$field, $part->$field, $field);
+            }
+        }
+
+        // Finally, we check the combined feedback fields for the parts and the main question.
+        $feedbackfields = ['correctfeedback', 'partiallycorrectfeedback', 'incorrectfeedback'];
+        foreach ($feedbackfields as $field) {
+            self::assertEquals($referencedata->$field, $questionrecord->options->$field, $field);
+            $fieldformat = $field . 'format';
+            self::assertEquals($referencedata->$fieldformat, $questionrecord->options->$fieldformat, $fieldformat);
+            $origfield = $field;
+            foreach ($questionrecord->options->answers as $i => $part) {
+                $field = 'part' . str_replace('feedback', 'fb', $origfield);
+                self::assertEquals($referencedata->parts[$i]->$field, $part->$field, $field);
+                $fieldformat = $field . 'format';
+                self::assertEquals($referencedata->parts[$i]->$fieldformat, $part->$fieldformat);
+            }
+        }
+
+        // Finally, compare the hints.
+        $hintfields = ['hint', 'hintformat', 'shownumcorrect', 'clearwrong'];
+        $keys = array_keys($questionrecord->hints);
+        foreach ($referencedata->hints as $i => $hint) {
+            foreach ($hintfields as $field) {
+                self::assertEquals($hint->$field, $questionrecord->hints[$keys[$i]]->$field, $field);
+            }
+        }
+    }
+}
diff --git a/tests/behat/export.feature b/tests/behat/export.feature
index 29c9a43c..1bdc0839 100644
--- a/tests/behat/export.feature
+++ b/tests/behat/export.feature
@@ -27,7 +27,7 @@ Feature: Test exporting Formulas questions
     When I am on the "Course 1" "core_question > course question export" page
     And I set the field "id_format_xml" to "1"
     And I press "Export questions to file"
-    Then following "click here" should download between "5400" and "5600" bytes
+    Then following "click here" should download between "6250" and "6500" bytes
     # If the download step is the last in the scenario then we can sometimes run
     # into the situation where the download page causes a http redirect but behat
     # has already conducted its reset (generating an error). By putting a logout
diff --git a/tests/behat/mobile.feature b/tests/behat/mobile.feature
index 49f8d8a7..67abcb6d 100644
--- a/tests/behat/mobile.feature
+++ b/tests/behat/mobile.feature
@@ -98,7 +98,7 @@ Feature: Mobile compatibility
     And I press "Submit" in the app
     And I press "Submit all and finish" in the app
     And I press "Submit" near "Once you submit" in the app
-    Then I should find "Your answer is correct." in the app
+    Then I should find "Correct answer, well done." in the app
 
   Scenario: Try to answer a question with one answer + one unit field
     When I press "Quiz 4" in the app
diff --git a/tests/behat/quiz.feature b/tests/behat/quiz.feature
index 26811045..1caf70e8 100644
--- a/tests/behat/quiz.feature
+++ b/tests/behat/quiz.feature
@@ -99,7 +99,7 @@ Feature: Usage in quiz
     And I press "Finish attempt"
     And I press "Submit all and finish"
     # And I confirm the quiz submission in the modal dialog
-    Then I should see "Your answer is correct."
+    Then I should see "Correct answer, well done."
 
   Scenario: Try to answer a question with one answer + one unit field
     When I follow "Quiz 4"
diff --git a/tests/helper.php b/tests/helper.php
index f087226f..89955ef3 100644
--- a/tests/helper.php
+++ b/tests/helper.php
@@ -113,7 +113,91 @@ protected static function make_a_formulas_part() {
     }
 
     /**
-     * @return qtype_formulas_question question, single part, one number as answer, no unit
+     * Create a single-part test question with answer type algebraic formula.
+     *
+     * @return qtype_formulas_question
+     */
+    public static function make_formulas_question_testalgebraic() {
+        $q = self::make_a_formulas_question();
+
+        $q->name = 'test-algebraic';
+        $q->questiontext = '<p>This is a minimal question. The answer is "5*x^2".</p>';
+
+        $q->penalty = 0.2;
+        $q->textfragments = [0 => '<p>This is a minimal question. The answer is "5*x^2".</p>',
+                                  1 => ''];
+        $q->numparts = 1;
+        $q->defaultmark = 1;
+        $q->varsglobal = 'a=5;';
+        $q->generalfeedback = '';
+        $p = self::make_a_formulas_part();
+        $p->id = 1;
+        $p->placeholder = '';
+        $p->answermark = 1;
+        $p->vars1 = 'x={1:10}';
+        $p->answer = '"a*x^2"';
+        $p->answertype = strval(qtype_formulas::ANSWER_TYPE_ALGEBRAIC);
+        $p->answernotunique = '1';
+        $p->correctness = '_err < 0.01';
+        $p->subqtext = '';
+        $p->partcorrectfb = 'Your answer is correct.';
+        $p->partpartiallycorrectfb = 'Your answer is partially correct.';
+        $p->partincorrectfb = 'Your answer is incorrect.';
+        $q->parts[0] = $p;
+        return $q;
+    }
+
+    /**
+     * Gets the question form data for the algebraic formulas question
+     * @return stdClass
+     */
+    public function get_formulas_question_form_data_testalgebraic() {
+        $form = new stdClass();
+
+        $form->name = 'test-algebraic';
+        $form->noanswers = 1;
+        $form->answer = ['"a*x^2"'];
+        $form->answernotunique = ['1'];
+        $form->answermark = [1];
+        $form->answertype = [strval(qtype_formulas::ANSWER_TYPE_ALGEBRAIC)];
+        $form->correctness = ['_err < 0.01'];
+        $form->numbox = [1];
+        $form->placeholder = [''];
+        $form->vars1 = ['x={1:10}'];
+        $form->vars2 = [''];
+        $form->postunit = [''];
+        $form->otherrule = [''];
+        $form->subqtext = [['text' => '', 'format' => FORMAT_HTML]];
+        $form->feedback = [['text' => '', 'format' => FORMAT_HTML]];
+        $form->partcorrectfb = [['text' => 'Your answer is correct.', 'format' => FORMAT_HTML]];
+        $form->partpartiallycorrectfb = [['text' => 'Your answer is partially correct.', 'format' => FORMAT_HTML]];
+        $form->partincorrectfb = [['text' => 'Your answer is incorrect.', 'format' => FORMAT_HTML]];
+        $form->questiontext = [
+            'text' => '<p>This is a minimal question. The answer is "5*x^2".</p>',
+            'format' => FORMAT_HTML,
+        ];
+        $form->generalfeedback = ['text' => '', 'format' => FORMAT_HTML];
+        $form->defaultmark = 2;
+        $form->penalty = 0.2;
+        $form->varsrandom = '';
+        $form->varsglobal = 'a=5;';
+        $form->answernumbering = 'abc';
+        $form->globalunitpenalty = 1;
+        $form->globalruleid = 1;
+        $form->correctfeedback = ['text' => test_question_maker::STANDARD_OVERALL_CORRECT_FEEDBACK, 'format' => FORMAT_HTML];
+        $form->partiallycorrectfeedback = [
+            'text' => test_question_maker::STANDARD_OVERALL_PARTIALLYCORRECT_FEEDBACK,
+            'format' => FORMAT_HTML,
+        ];
+        $form->incorrectfeedback = ['text' => test_question_maker::STANDARD_OVERALL_INCORRECT_FEEDBACK, 'format' => FORMAT_HTML];
+        $form->shownumcorrect = '1';
+        return $form;
+    }
+
+    /**
+     * Create a single-part test question with answer type number.
+     *
+     * @return qtype_formulas_question
      */
     public static function make_formulas_question_testsinglenum() {
         $q = self::make_a_formulas_question();
@@ -187,10 +271,19 @@ public function get_formulas_question_form_data_testsinglenum() {
         $form->answernumbering = 'abc';
         $form->globalunitpenalty = 1;
         $form->globalruleid = 1;
-        $form->correctfeedback = array('text' => '', 'format' => FORMAT_HTML);
-        $form->partiallycorrectfeedback = array('text' => '', 'format' => FORMAT_HTML);
-        $form->shownumcorrect = '0';
-        $form->incorrectfeedback = array('text' => '', 'format' => FORMAT_HTML);
+        $form->correctfeedback = ['text' => test_question_maker::STANDARD_OVERALL_CORRECT_FEEDBACK, 'format' => FORMAT_HTML];
+        $form->partiallycorrectfeedback = [
+            'text' => test_question_maker::STANDARD_OVERALL_PARTIALLYCORRECT_FEEDBACK,
+            'format' => FORMAT_HTML,
+        ];
+        $form->incorrectfeedback = ['text' => test_question_maker::STANDARD_OVERALL_INCORRECT_FEEDBACK, 'format' => FORMAT_HTML];
+        $form->shownumcorrect = '1';
+        $form->hint = [
+            ['text' => 'Hint 1.', 'format' => FORMAT_HTML],
+            ['text' => 'Hint 2.', 'format' => FORMAT_HTML],
+        ];
+        $form->hintclearwrong = [0, 1];
+        $form->hintshownumcorrect = [1, 1];
         return $form;
     }
 
@@ -232,37 +325,35 @@ public function get_formulas_question_form_data_testsinglenumunit() {
 
         $form->name = 'test-0';
         $form->noanswers = 1;
-        $form->answer = array('5');
-        $form->answernotunique = array('1');
-        $form->answermark = array(2);
-        $form->answertype = array(0);
-        $form->correctness = array('_relerr < 0.01');
-        $form->numbox = array(1);
-        $form->placeholder = array('');
-        $form->vars1 = array('');
-        $form->vars2 = array('');
-        $form->ruleid = array(1);
-        $form->unitpenalty = array(1);
-        $form->postunit = array('m/s');
-        $form->otherrule = array('');
-        $form->subqtext = array(
-            array('text' => '{_0}{_u}', 'format' => FORMAT_HTML)
-        );
-        $form->feedback = array(
-            array('text' => '', 'format' => FORMAT_HTML)
-        );
-        $form->partcorrectfb = array(
-            array('text' => 'Your answer is correct.', 'format' => FORMAT_HTML)
-        );
-        $form->partpartiallycorrectfb = array(
-            array('text' => 'Your answer is partially correct.', 'format' => FORMAT_HTML)
-        );
-        $form->partincorrectfb = array(
-            array('text' => 'Your answer is incorrect.', 'format' => FORMAT_HTML)
-        );
-        $form->questiontext = array('text' => '<p>One part, one number plus unit, answer is 5 m/s</p>',
-                'format' => FORMAT_HTML);
-        $form->generalfeedback = array('text' => '', 'format' => FORMAT_HTML);
+        $form->answer = ['5'];
+        $form->answernotunique = ['1'];
+        $form->answermark = [2];
+        $form->answertype = ['0'];
+        $form->correctness = ['_relerr < 0.01'];
+        $form->numbox = [1];
+        $form->placeholder = [''];
+        $form->vars1 = [''];
+        $form->vars2 = [''];
+        $form->postunit = ['m/s'];
+        $form->otherrule = [''];
+        $form->subqtext = [
+            ['text' => '{_0}{_u}', 'format' => FORMAT_HTML],
+        ];
+        $form->feedback = [
+            ['text' => '', 'format' => FORMAT_HTML],
+        ];
+        $form->partcorrectfb = [
+            ['text' => '<p>Correct answer, well done.</p>', 'format' => FORMAT_HTML],
+        ];
+        $form->partpartiallycorrectfb = [
+            ['text' => '<p>Your answer is partially correct.</p>', 'format' => FORMAT_HTML],
+        ];
+        $form->partincorrectfb = [
+            ['text' => '<p>Incorrect answer.</p>', 'format' => FORMAT_HTML],
+        ];
+        $form->questiontext = ['text' => '<p>One part, one number plus unit, answer is 5 m/s</p>',
+                'format' => FORMAT_HTML];
+        $form->generalfeedback = ['text' => '', 'format' => FORMAT_HTML];
         $form->defaultmark = 2;
         $form->penalty = 0.3;
         $form->varsrandom = '';
@@ -270,10 +361,13 @@ public function get_formulas_question_form_data_testsinglenumunit() {
         $form->answernumbering = 'abc';
         $form->globalunitpenalty = 1;
         $form->globalruleid = 1;
-        $form->correctfeedback = array('text' => '', 'format' => FORMAT_HTML);
-        $form->partiallycorrectfeedback = array('text' => '', 'format' => FORMAT_HTML);
+        $form->correctfeedback = ['text' => 'Well done!', 'format' => FORMAT_HTML];
+        $form->partiallycorrectfeedback = [
+            'text' => 'Parts, but only parts, of your response are correct.',
+            'format' => FORMAT_HTML,
+        ];
         $form->shownumcorrect = '0';
-        $form->incorrectfeedback = array('text' => '', 'format' => FORMAT_HTML);
+        $form->incorrectfeedback = ['text' => 'That is not right at all.', 'format' => FORMAT_HTML];
         return $form;
     }
 
@@ -313,7 +407,7 @@ public static function make_formulas_question_testsinglenumunitsep() {
     public function get_formulas_question_form_data_testsinglenumunitsep() {
         $form = new stdClass();
 
-        $form->name = 'test-0';
+        $form->name = 'test-singlenumunitsep';
         $form->noanswers = 1;
         $form->answer = array('5');
         $form->answernotunique = array('1');
@@ -353,10 +447,13 @@ public function get_formulas_question_form_data_testsinglenumunitsep() {
         $form->answernumbering = 'abc';
         $form->globalunitpenalty = 1;
         $form->globalruleid = 1;
-        $form->correctfeedback = array('text' => '', 'format' => FORMAT_HTML);
-        $form->partiallycorrectfeedback = array('text' => '', 'format' => FORMAT_HTML);
+        $form->correctfeedback = ['text' => 'Well done!', 'format' => FORMAT_HTML];
+        $form->partiallycorrectfeedback = [
+            'text' => 'Parts, but only parts, of your response are correct.',
+            'format' => FORMAT_HTML,
+        ];
         $form->shownumcorrect = '0';
-        $form->incorrectfeedback = array('text' => '', 'format' => FORMAT_HTML);
+        $form->incorrectfeedback = ['text' => 'That is not right at all.', 'format' => FORMAT_HTML];
         return $form;
     }
 
@@ -379,6 +476,7 @@ public static function make_formulas_question_testtwonums() {
         $p->placeholder = '';
         $p->answermark = 2;
         $p->answer = '[2, 3]';
+        $p->numbox = 2;
         $p->answernotunique = '1';
         $p->subqtext = '';
         $p->partcorrectfb = 'Your answer is correct.';
@@ -397,37 +495,35 @@ public function get_formulas_question_form_data_testtwonums() {
 
         $form->name = 'test-1';
         $form->noanswers = 1;
-        $form->answer = array('[2, 3]');
-        $form->answernotunique = array('1');
-        $form->answermark = array(2);
-        $form->answertype = array(0);
-        $form->correctness = array('_relerr < 0.01');
-        $form->numbox = array(1, 1);
-        $form->placeholder = array('');
-        $form->vars1 = array('');
-        $form->vars2 = array('');
-        $form->ruleid = array(1);
-        $form->unitpenalty = array(1);
-        $form->postunit = array('');
-        $form->otherrule = array('');
-        $form->subqtext = array(
-            array('text' => '', 'format' => FORMAT_HTML)
-        );
-        $form->feedback = array(
-            array('text' => '', 'format' => FORMAT_HTML)
-        );
-        $form->partcorrectfb = array(
-            array('text' => 'Your answer is correct.', 'format' => FORMAT_HTML)
-        );
-        $form->partpartiallycorrectfb = array(
-            array('text' => 'Your answer is partially correct.', 'format' => FORMAT_HTML)
-        );
-        $form->partincorrectfb = array(
-            array('text' => 'Your answer is incorrect.', 'format' => FORMAT_HTML)
-        );
-        $form->questiontext = array('text' => '<p>Question with two numbers. The answers are 2 and 3.</p>',
-                'format' => FORMAT_HTML);
-        $form->generalfeedback = array('text' => '', 'format' => FORMAT_HTML);
+        $form->answer = ['[2, 3]'];
+        $form->answernotunique = ['1'];
+        $form->answermark = [2];
+        $form->answertype = ['0'];
+        $form->correctness = ['_relerr < 0.01'];
+        $form->numbox = [2];
+        $form->placeholder = [''];
+        $form->vars1 = [''];
+        $form->vars2 = [''];
+        $form->postunit = [''];
+        $form->otherrule = [''];
+        $form->subqtext = [
+            ['text' => '', 'format' => FORMAT_HTML],
+        ];
+        $form->feedback = [
+            ['text' => '', 'format' => FORMAT_HTML],
+        ];
+        $form->partcorrectfb = [
+            ['text' => 'Your answer is correct.', 'format' => FORMAT_HTML],
+        ];
+        $form->partpartiallycorrectfb = [
+            ['text' => 'Your answer is partially correct.', 'format' => FORMAT_HTML],
+        ];
+        $form->partincorrectfb = [
+            ['text' => 'Your answer is incorrect.', 'format' => FORMAT_HTML],
+        ];
+        $form->questiontext = ['text' => '<p>Question with two numbers. The answers are 2 and 3.</p>',
+                'format' => FORMAT_HTML];
+        $form->generalfeedback = ['text' => '', 'format' => FORMAT_HTML];
         $form->defaultmark = 2;
         $form->penalty = 0.3;
         $form->varsrandom = '';
@@ -435,10 +531,13 @@ public function get_formulas_question_form_data_testtwonums() {
         $form->answernumbering = '';
         $form->globalunitpenalty = 1;
         $form->globalruleid = 1;
-        $form->correctfeedback = array('text' => '', 'format' => FORMAT_HTML);
-        $form->partiallycorrectfeedback = array('text' => '', 'format' => FORMAT_HTML);
+        $form->correctfeedback = ['text' => 'Well done!', 'format' => FORMAT_HTML];
+        $form->partiallycorrectfeedback = [
+            'text' => 'Parts, but only parts, of your response are correct.',
+            'format' => FORMAT_HTML,
+        ];
         $form->shownumcorrect = '0';
-        $form->incorrectfeedback = array('text' => '', 'format' => FORMAT_HTML);
+        $form->incorrectfeedback = ['text' => 'That is not right at all.', 'format' => FORMAT_HTML];
         return $form;
     }
 
@@ -529,35 +628,38 @@ public function get_formulas_question_form_data_testthreeparts() {
         $form->otherrule = array('', '', '');
         $form->globalunitpenalty = 1;
         $form->globalruleid = 1;
-        $form->subqtext = array(
-            array('text' => 'This is first part.', 'format' => FORMAT_HTML),
-            array('text' => 'This is second part.', 'format' => FORMAT_HTML),
-            array('text' => 'This is third part.', 'format' => FORMAT_HTML),
-        );
-        $form->feedback = array(
-            array('text' => '', 'format' => FORMAT_HTML),
-            array('text' => '', 'format' => FORMAT_HTML),
-            array('text' => '', 'format' => FORMAT_HTML),
-        );
-        $form->partcorrectfb = array(
-            array('text' => 'Part 1 correct feedback.', 'format' => FORMAT_HTML),
-            array('text' => 'Part 2 correct feedback.', 'format' => FORMAT_HTML),
-            array('text' => 'Part 3 correct feedback.', 'format' => FORMAT_HTML),
-        );
-        $form->partpartiallycorrectfb = array(
-            array('text' => 'Part 1 partially correct feedback.', 'format' => FORMAT_HTML),
-            array('text' => 'Part 2 partially correct feedback.', 'format' => FORMAT_HTML),
-            array('text' => 'Part 3 partially correct feedback.', 'format' => FORMAT_HTML),
-        );
-        $form->partincorrectfb = array(
-            array('text' => 'Part 1 incorrect feedback.', 'format' => FORMAT_HTML),
-            array('text' => 'Part 2 incorrect feedback.', 'format' => FORMAT_HTML),
-            array('text' => 'Part 3 incorrect feedback.', 'format' => FORMAT_HTML),
-        );
-        $form->correctfeedback = array('text' => '', 'format' => FORMAT_HTML);
-        $form->partiallycorrectfeedback = array('text' => '', 'format' => FORMAT_HTML);
+        $form->subqtext = [
+            ['text' => 'This is first part.', 'format' => FORMAT_HTML],
+            ['text' => 'This is second part.', 'format' => FORMAT_HTML],
+            ['text' => 'This is third part.', 'format' => FORMAT_HTML],
+        ];
+        $form->feedback = [
+            ['text' => '', 'format' => FORMAT_HTML],
+            ['text' => '', 'format' => FORMAT_HTML],
+            ['text' => '', 'format' => FORMAT_HTML],
+        ];
+        $form->partcorrectfb = [
+            ['text' => 'Part 1 correct feedback.', 'format' => FORMAT_HTML],
+            ['text' => 'Part 2 correct feedback.', 'format' => FORMAT_HTML],
+            ['text' => 'Part 3 correct feedback.', 'format' => FORMAT_HTML],
+        ];
+        $form->partpartiallycorrectfb = [
+            ['text' => 'Part 1 partially correct feedback.', 'format' => FORMAT_HTML],
+            ['text' => 'Part 2 partially correct feedback.', 'format' => FORMAT_HTML],
+            ['text' => 'Part 3 partially correct feedback.', 'format' => FORMAT_HTML],
+        ];
+        $form->partincorrectfb = [
+            ['text' => 'Part 1 incorrect feedback.', 'format' => FORMAT_HTML],
+            ['text' => 'Part 2 incorrect feedback.', 'format' => FORMAT_HTML],
+            ['text' => 'Part 3 incorrect feedback.', 'format' => FORMAT_HTML],
+        ];
+        $form->correctfeedback = ['text' => 'Well done!', 'format' => FORMAT_HTML];
+        $form->partiallycorrectfeedback = [
+            'text' => 'Parts, but only parts, of your response are correct.',
+            'format' => FORMAT_HTML,
+        ];
         $form->shownumcorrect = '0';
-        $form->incorrectfeedback = array('text' => '', 'format' => FORMAT_HTML);
+        $form->incorrectfeedback = ['text' => 'That is not right at all.', 'format' => FORMAT_HTML];
         $form->numhints = 2;
         $form->hint = array(
             array('text' => '', 'format' => FORMAT_HTML),
@@ -580,7 +682,8 @@ public static function make_formulas_question_testmethodsinparts() {
         $q->defaultmark = 8;
         $q->penalty = 0.3; // Non-zero and not the default.
         $q->numpart = 4;
-        $q->textfragments = array(0 => '<p>This question shows different display methods of the answer and unit box.</p>',
+        $q->generalfeedback = 'This is the general feedback.';
+        $q->textfragments = [0 => '<p>This question shows different display methods of the answer and unit box.</p>',
                 1 => '',
                 2 => '',
                 3 => '',
@@ -643,9 +746,7 @@ public static function get_formulas_question_data_testmethodsinparts() {
         $qdata->qtype = 'formulas';
         $qdata->name = 'test-2';
         $qdata->questiontext = '<p>This question shows different display methods of the answer and unit box.</p>';
-        $qdata->questiontextformat = FORMAT_HTML;
-        $qdata->generalfeedback = '';
-        $qdata->generalfeedbackformat = FORMAT_HTML;
+        $qdata->generalfeedback = 'This is the general feedback.';
         $qdata->defaultmark = 8;
         $qdata->length = 1;
         $qdata->penalty = 0.3;
@@ -943,12 +1044,12 @@ public function get_formulas_question_form_data_testmethodsinparts() {
         $form->shownumcorrect = '0';
         $form->incorrectfeedback = array('text' => '', 'format' => FORMAT_HTML);
         $form->numhints = 2;
-        $form->hint = array(
-            array('text' => '', 'format' => FORMAT_HTML),
-            array('text' => '', 'format' => FORMAT_HTML),
-        );
-        $form->hintclearwrong = array('0', '0');
-        $form->hintshownumcorrect = array('0', '0');
+        $form->hint = [
+            ['text' => 'Hint 1.', 'format' => FORMAT_HTML],
+            ['text' => 'Hint 2.', 'format' => FORMAT_HTML],
+        ];
+        $form->hintclearwrong = [0, 1];
+        $form->hintshownumcorrect = [1, 1];
         return $form;
     }
 
@@ -1042,7 +1143,8 @@ public static function make_formulas_question_test4() {
         $q->defaultmark = 8;
         $q->penalty = 0.3; // Non-zero and not the default.
         $q->numpart = 4;
-        $q->textfragments = array(0 => '<p>This question shows different display methods of the answer and unit box.</p>',
+        $q->generalfeedback = 'This is the general feedback.';
+        $q->textfragments = [0 => '<p>This question shows different display methods of the answer and unit box.</p>',
                 1 => '',
                 2 => '',
                 3 => '',
@@ -1139,37 +1241,40 @@ public function get_formulas_question_form_data_test4() {
             ),
             array(
               'text' => '<p>If a car travels {s} m in {dt} s, what is the speed of the car? speed = {_0}{_u}</p>',
-              'format' => FORMAT_HTML
-            ),
-        );
-        $form->feedback = array(
-            array('text' => '', 'format' => FORMAT_HTML),
-            array('text' => '', 'format' => FORMAT_HTML),
-            array('text' => '', 'format' => FORMAT_HTML),
-            array('text' => '', 'format' => FORMAT_HTML),
-        );
-        $form->partcorrectfb = array(
-            array('text' => '', 'format' => FORMAT_HTML),
-            array('text' => '', 'format' => FORMAT_HTML),
-            array('text' => '', 'format' => FORMAT_HTML),
-            array('text' => '', 'format' => FORMAT_HTML),
-        );
-        $form->partpartiallycorrectfb = array(
-            array('text' => '', 'format' => FORMAT_HTML),
-            array('text' => '', 'format' => FORMAT_HTML),
-            array('text' => '', 'format' => FORMAT_HTML),
-            array('text' => '', 'format' => FORMAT_HTML),
-        );
-        $form->partincorrectfb = array(
-            array('text' => '', 'format' => FORMAT_HTML),
-            array('text' => '', 'format' => FORMAT_HTML),
-            array('text' => '', 'format' => FORMAT_HTML),
-            array('text' => '', 'format' => FORMAT_HTML),
-        );
-        $form->correctfeedback = array('text' => '', 'format' => FORMAT_HTML);
-        $form->partiallycorrectfeedback = array('text' => '', 'format' => FORMAT_HTML);
+              'format' => FORMAT_HTML,
+            ],
+        ];
+        $form->feedback = [
+            ['text' => '', 'format' => FORMAT_HTML],
+            ['text' => '', 'format' => FORMAT_HTML],
+            ['text' => '', 'format' => FORMAT_HTML],
+            ['text' => '', 'format' => FORMAT_HTML],
+        ];
+        $form->partcorrectfb = [
+            ['text' => self::DEFAULT_CORRECT_FEEDBACK, 'format' => FORMAT_HTML],
+            ['text' => self::DEFAULT_CORRECT_FEEDBACK, 'format' => FORMAT_HTML],
+            ['text' => self::DEFAULT_CORRECT_FEEDBACK, 'format' => FORMAT_HTML],
+            ['text' => self::DEFAULT_CORRECT_FEEDBACK, 'format' => FORMAT_HTML],
+        ];
+        $form->partpartiallycorrectfb = [
+            ['text' => self::DEFAULT_PARTIALLYCORRECT_FEEDBACK, 'format' => FORMAT_HTML],
+            ['text' => self::DEFAULT_PARTIALLYCORRECT_FEEDBACK, 'format' => FORMAT_HTML],
+            ['text' => self::DEFAULT_PARTIALLYCORRECT_FEEDBACK, 'format' => FORMAT_HTML],
+            ['text' => self::DEFAULT_PARTIALLYCORRECT_FEEDBACK, 'format' => FORMAT_HTML],
+        ];
+        $form->partincorrectfb = [
+            ['text' => self::DEFAULT_INCORRECT_FEEDBACK, 'format' => FORMAT_HTML],
+            ['text' => self::DEFAULT_INCORRECT_FEEDBACK, 'format' => FORMAT_HTML],
+            ['text' => self::DEFAULT_INCORRECT_FEEDBACK, 'format' => FORMAT_HTML],
+            ['text' => self::DEFAULT_INCORRECT_FEEDBACK, 'format' => FORMAT_HTML],
+        ];
+        $form->correctfeedback = ['text' => 'Well done!', 'format' => FORMAT_HTML];
+        $form->partiallycorrectfeedback = [
+            'text' => 'Parts, but only parts, of your response are correct.',
+            'format' => FORMAT_HTML,
+        ];
         $form->shownumcorrect = '0';
-        $form->incorrectfeedback = array('text' => '', 'format' => FORMAT_HTML);
+        $form->incorrectfeedback = ['text' => 'That is not right at all.', 'format' => FORMAT_HTML];
         $form->numhints = 2;
         $form->hint = array(
             array('text' => '', 'format' => FORMAT_HTML),

From cea5d345a1c4c6166a6f79d3b60737af8c884370 Mon Sep 17 00:00:00 2001
From: Philipp Imhof <52650214+PhilippImhof@users.noreply.github.com>
Date: Sun, 16 Mar 2025 11:12:07 +0100
Subject: [PATCH 2/5] add unit test for backup and restore

---
 tests/backup_restore_test.php |    2 +-
 tests/helper.php              | 1582 +++++++++++++++++++++------------
 2 files changed, 990 insertions(+), 594 deletions(-)

diff --git a/tests/backup_restore_test.php b/tests/backup_restore_test.php
index c27af3cf..646efd39 100644
--- a/tests/backup_restore_test.php
+++ b/tests/backup_restore_test.php
@@ -161,7 +161,7 @@ public function test_backup_and_restore(string $questionname): void {
         }
 
         // Next, we check the fields for each part.
-        $partfields = qtype_formulas::PART_BASIC_FIELDS + ['subqtext', 'subqtextformat', 'feedback', 'feedbackformat'];
+        $partfields = $qtype->part_tags() + ['subqtext', 'subqtextformat', 'feedback', 'feedbackformat'];
         foreach ($partfields as $field) {
             foreach ($questionrecord->options->answers as $i => $part) {
                 self::assertEquals($referencedata->parts[$i]->$field, $part->$field, $field);
diff --git a/tests/helper.php b/tests/helper.php
index 89955ef3..88a80f42 100644
--- a/tests/helper.php
+++ b/tests/helper.php
@@ -14,41 +14,59 @@
 // You should have received a copy of the GNU General Public License
 // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
 
-/**
- * Test helper code for the formulas question type.
- *
- * @package    qtype_formulas
- * @copyright  2012 Jean-Michel Védrine
- * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
- */
-
 /**
  * Test helper class for the formulas question type.
  *
+ * @package    qtype_formulas
  * @copyright  2012 Jean-Michel Védrine
  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  */
 class qtype_formulas_test_helper extends question_test_helper {
-    const DEFAULT_CORRECT_FEEDBACK          = '<p>Correct answer, well done.</p>';
+    /** @var string */
+    const DEFAULT_CORRECT_FEEDBACK = '<p>Correct answer, well done.</p>';
+
+    /** @var string */
     const DEFAULT_PARTIALLYCORRECT_FEEDBACK = '<p>Your answer is partially correct.</p>';
-    const DEFAULT_INCORRECT_FEEDBACK        = '<p>Incorrect answer.</p>';
-
-    public function get_test_questions() {
-        return array(
-            'testsinglenum', // Minimal formulas question : one part, not randomised (answer = 5),
-            'testtwonums', // Minimal formulas question : one part, two numbers (2 and 3),
-            'testsinglenumunit', // one part, one number with unit (answer: 5 m/s),
-            'testsinglenumunitsep', // one part, one number plus separate unit (answer: 5 m/s),
-            'testzero', // one part, not randomized, answer = 0 (to test problem with 0 as answer),
-            'testmce', // One part not randomized drowdown multichoice answer.
-            'testmc', // One part not randomized radiobutton multichoice answer.
-            'testthreeparts', // 3 parts, not randomised. (answers = 5, 6, 7),
-            'testmethodsinparts', // 4 parts, separated and combined unit field, not ramdomized,
-            'testmcetwoparts', // 2 parts, each one with an MCE (dropdown) question
-            'testmctwoparts', // 2 parts, each one with an MC (radio) question
-            'testtwoandtwo', // 2 parts, each one with 2 numbers
-            'test4', // 4 parts, separated and combined unit field, ramdomized.
-        );
+
+    /** @var string */
+    const DEFAULT_INCORRECT_FEEDBACK = '<p>Incorrect answer.</p>';
+
+    /**
+     * Return a list of possible test questions.
+     *
+     * @return array
+     */
+    public function get_test_questions(): array {
+        return [
+            // Minimal formulas question: one part, not randomised, answer = 5.
+            'testsinglenum',
+             // Formulas question with algebraic answer.
+            'testalgebraic',
+             // Minimal formulas question: one part, two numbers, answer = 2 and 3.
+            'testtwonums',
+            // Formulas question with one part, one number with unit (combined), answer = 5 m/s.
+            'testsinglenumunit',
+            // Formulas question with one part, one number with unit (separate), answer = 5 m/s.
+            'testsinglenumunitsep',
+            // Formulas question with one part, not randomized, answer = 0, used to test for problems with 0 as answer.
+            'testzero',
+            // Formulas question with one part, not randomized, drowdown multichoice answer.
+            'testmce',
+            // Formulas question with one part, not randomized, radio button multichoice answer.
+            'testmc',
+            // Formulas question with 3 parts, not randomised, answers = 5, 6, 7.
+            'testthreeparts',
+            // Formulas question with 4 parts, not randomised, separate and combined unit fields.
+            'testmethodsinparts',
+            // Formulas question with 2 parts, each with a drowdown multichoice answer.
+            'testmcetwoparts',
+            // Formulas question with 2 parts, each with a radio button multichoice answer.
+            'testmctwoparts',
+            // Formulas question with 2 parts, each one with 2 numbers.
+            'testtwoandtwo',
+            // Formulas question with 4 parts, randomised, separate and combined unit fields.
+            'test4',
+        ];
     }
 
     /**
@@ -65,28 +83,29 @@ protected static function make_a_formulas_question() {
         $q->contextid = context_system::instance()->id;
         $q->varsrandom = '';
         $q->varsglobal = '';
-        $q->shownumcorrect = 0;
         $q->answernumbering = 'abc';
-        $q->qv = new qtype_formulas\variables();
-        $q->penalty = 0.2; // The default.
+        $q->penalty = 0.2;
+        $q->generalfeedback = '';
         test_question_maker::set_standard_combined_feedback_fields($q);
+        $q->shownumcorrect = 1;
         $q->numpart = 0;   // This is of course invalid but should be changed by all tests.
-        $q->parts = array();
-        $q->evaluatedanswer = array();
-        $q->fractions = array();
-        $q->anscorrs = array();
-        $q->unitcorrs = array();
+        $q->parts = [];
         return $q;
     }
 
-    protected static function make_a_formulas_part() {
+    /**
+     * Create a qtype_formulas_part object for testing.
+     *
+     * @return qtype_formulas_part
+     */
+    protected static function make_a_formulas_part(): qtype_formulas_part {
         question_bank::load_question_definition_classes('formulas');
 
         $p = new qtype_formulas_part();
         $p->id = 0;
         $p->placeholder = '';
         $p->answermark = 1;
-        $p->answertype = 0;
+        $p->answertype = '0';
         $p->numbox = 1;
         $p->vars1 = '';
         $p->vars2 = '';
@@ -98,15 +117,15 @@ protected static function make_a_formulas_part() {
         $p->ruleid = 1;
         $p->otherrule = '';
         $p->subqtext = '';
-        $p->subqtextformat = 1;
+        $p->subqtextformat = FORMAT_HTML;
         $p->feedback = '';
-        $p->feedbackformat = 1;
-        $p->partcorrectfb = '';
-        $p->partcorrectfbformat = 1;
-        $p->partpartiallycorrectfb = '';
-        $p->partpartiallycorrectfbformat = 1;
-        $p->partincorrectfb = '';
-        $p->partincorrectfbformat = 1;
+        $p->feedbackformat = FORMAT_HTML;
+        $p->partcorrectfb = self::DEFAULT_CORRECT_FEEDBACK;
+        $p->partcorrectfbformat = FORMAT_HTML;
+        $p->partpartiallycorrectfb = self::DEFAULT_PARTIALLYCORRECT_FEEDBACK;
+        $p->partpartiallycorrectfbformat = FORMAT_HTML;
+        $p->partincorrectfb = self::DEFAULT_INCORRECT_FEEDBACK;
+        $p->partincorrectfbformat = FORMAT_HTML;
         $p->partindex = 0;
 
         return $p;
@@ -126,7 +145,7 @@ public static function make_formulas_question_testalgebraic() {
         $q->penalty = 0.2;
         $q->textfragments = [0 => '<p>This is a minimal question. The answer is "5*x^2".</p>',
                                   1 => ''];
-        $q->numparts = 1;
+        $q->numpart = 1;
         $q->defaultmark = 1;
         $q->varsglobal = 'a=5;';
         $q->generalfeedback = '';
@@ -136,7 +155,7 @@ public static function make_formulas_question_testalgebraic() {
         $p->answermark = 1;
         $p->vars1 = 'x={1:10}';
         $p->answer = '"a*x^2"';
-        $p->answertype = strval(qtype_formulas::ANSWER_TYPE_ALGEBRAIC);
+        $p->answertype = '1000';
         $p->answernotunique = '1';
         $p->correctness = '_err < 0.01';
         $p->subqtext = '';
@@ -159,7 +178,7 @@ public function get_formulas_question_form_data_testalgebraic() {
         $form->answer = ['"a*x^2"'];
         $form->answernotunique = ['1'];
         $form->answermark = [1];
-        $form->answertype = [strval(qtype_formulas::ANSWER_TYPE_ALGEBRAIC)];
+        $form->answertype = ['1000'];
         $form->correctness = ['_err < 0.01'];
         $form->numbox = [1];
         $form->placeholder = [''];
@@ -202,68 +221,71 @@ public function get_formulas_question_form_data_testalgebraic() {
     public static function make_formulas_question_testsinglenum() {
         $q = self::make_a_formulas_question();
 
-        $q->name = 'test-0';
+        $q->name = 'test-singlenum';
         $q->questiontext = '<p>This is a minimal question. The answer is 5.</p>';
 
         $q->penalty = 0.3; // Non-zero and not the default.
-        $q->textfragments = array(0 => '<p>This is a minimal question. The answer is 5.</p>',
-                                  1 => '');
+        $q->textfragments = [0 => '<p>This is a minimal question. The answer is 5.</p>',
+                                  1 => ''];
         $q->numpart = 1;
         $q->defaultmark = 2;
+        $q->generalfeedback = '';
         $p = self::make_a_formulas_part();
+        $p->questionid = $q->id;
         $p->id = 14;
         $p->placeholder = '';
         $p->answermark = 2;
         $p->answer = '5';
         $p->answernotunique = '1';
         $p->subqtext = '';
-        $p->partcorrectfb = 'Your answer is correct.';
-        $p->partpartiallycorrectfb = 'Your answer is partially correct.';
-        $p->partincorrectfb = 'Your answer is incorrect.';
         $q->parts[0] = $p;
+
+        $q->hints = [
+            new question_hint_with_parts(101, 'Hint 1.', FORMAT_HTML, 1, 0),
+            new question_hint_with_parts(102, 'Hint 2.', FORMAT_HTML, 1, 1),
+        ];
         return $q;
     }
 
     /**
      * Gets the question form data for the singlenum formulas question
+     *
      * @return stdClass
      */
-    public function get_formulas_question_form_data_testsinglenum() {
+    public function get_formulas_question_form_data_testsinglenum(): stdClass {
         $form = new stdClass();
 
-        $form->name = 'test-0';
+        $form->name = 'test-singlenum';
         $form->noanswers = 1;
-        $form->answer = array('5');
-        $form->answernotunique = array('1');
-        $form->answermark = array(2);
-        $form->answertype = array(0);
-        $form->correctness = array('_relerr < 0.01');
-        $form->numbox = array(1);
-        $form->placeholder = array('');
-        $form->vars1 = array('');
-        $form->vars2 = array('');
-        $form->ruleid = array(1);
-        $form->unitpenalty = array(1);
-        $form->postunit = array('');
-        $form->otherrule = array('');
-        $form->subqtext = array(
-            array('text' => '', 'format' => FORMAT_HTML)
-        );
-        $form->feedback = array(
-            array('text' => '', 'format' => FORMAT_HTML)
-        );
-        $form->partcorrectfb = array(
-            array('text' => 'Your answer is correct.', 'format' => FORMAT_HTML)
-        );
-        $form->partpartiallycorrectfb = array(
-            array('text' => 'Your answer is partially correct.', 'format' => FORMAT_HTML)
-        );
-        $form->partincorrectfb = array(
-            array('text' => 'Your answer is incorrect.', 'format' => FORMAT_HTML)
-        );
-        $form->questiontext = array('text' => '<p>This is a minimal question. The answer is 5.</p>',
-                'format' => FORMAT_HTML);
-        $form->generalfeedback = array('text' => '', 'format' => FORMAT_HTML);
+        $form->answer = ['5'];
+        $form->answernotunique = ['1'];
+        $form->answermark = [2];
+        $form->answertype = ['0'];
+        $form->correctness = ['_relerr < 0.01'];
+        $form->numbox = [1];
+        $form->placeholder = [''];
+        $form->vars1 = [''];
+        $form->vars2 = [''];
+        $form->postunit = [''];
+        $form->otherrule = [''];
+        $form->subqtext = [
+            ['text' => '', 'format' => FORMAT_HTML],
+        ];
+        $form->feedback = [
+            ['text' => '', 'format' => FORMAT_HTML],
+        ];
+        $form->partcorrectfb = [
+            ['text' => self::DEFAULT_CORRECT_FEEDBACK, 'format' => FORMAT_HTML],
+        ];
+        $form->partpartiallycorrectfb = [
+            ['text' => self::DEFAULT_PARTIALLYCORRECT_FEEDBACK, 'format' => FORMAT_HTML],
+        ];
+        $form->partincorrectfb = [
+            ['text' => self::DEFAULT_INCORRECT_FEEDBACK, 'format' => FORMAT_HTML],
+        ];
+        $form->questiontext = ['text' => '<p>This is a minimal question. The answer is 5.</p>',
+                'format' => FORMAT_HTML];
+        $form->generalfeedback = ['text' => '', 'format' => FORMAT_HTML];
         $form->defaultmark = 2;
         $form->penalty = 0.3;
         $form->varsrandom = '';
@@ -288,30 +310,118 @@ public function get_formulas_question_form_data_testsinglenum() {
     }
 
     /**
-     * @return qtype_formulas_question one part, one number with unit
+     * Return question data for a single-part question with answer type number.
+     *
+     * @return stdClass
      */
-    public static function make_formulas_question_testsinglenumunit() {
+    public static function get_formulas_question_data_testsinglenum(): stdClass {
+        $qdata = new stdClass();
+        test_question_maker::initialise_question_data($qdata);
+
+        $qdata->qtype = 'formulas';
+        $qdata->name = 'test-singlenum';
+        $qdata->questiontext = '<p>This is a minimal question. The answer is 5.</p>';
+        $qdata->generalfeedback = '';
+        $qdata->defaultmark = 2;
+        $qdata->penalty = 0.3;
+
+        $qdata->options = new stdClass();
+        $qdata->contextid = context_system::instance()->id;
+        $qdata->options->varsrandom = '';
+        $qdata->options->varsglobal = '';
+        $qdata->options->answernumbering = 'abc';
+        $qdata->options->shownumcorrect = 1;
+        $qdata->options->correctfeedback =
+                test_question_maker::STANDARD_OVERALL_CORRECT_FEEDBACK;
+        $qdata->options->correctfeedbackformat = FORMAT_HTML;
+        $qdata->options->partiallycorrectfeedback =
+                test_question_maker::STANDARD_OVERALL_PARTIALLYCORRECT_FEEDBACK;
+        $qdata->options->partiallycorrectfeedbackformat = FORMAT_HTML;
+        $qdata->options->incorrectfeedback =
+                test_question_maker::STANDARD_OVERALL_INCORRECT_FEEDBACK;
+        $qdata->options->incorrectfeedbackformat = FORMAT_HTML;
+
+        $qdata->options->answers = [
+            14 => (object) [
+                'id' => 14,
+                'questionid' => $qdata->id,
+                'placeholder' => '',
+                'answermark' => 2,
+                'answertype' => '0',
+                'numbox' => 1,
+                'vars1' => '',
+                'vars2' => '',
+                'answer' => '5',
+                'answernotunique' => '1',
+                'correctness' => '_relerr < 0.01',
+                'unitpenalty' => 1,
+                'postunit' => '',
+                'ruleid' => 1,
+                'otherrule' => '',
+                'subqtext' => '',
+                'subqtextformat' => FORMAT_HTML,
+                'feedback' => '',
+                'feedbackformat' => FORMAT_HTML,
+                'partcorrectfb' => self::DEFAULT_CORRECT_FEEDBACK,
+                'partcorrectfbformat' => FORMAT_HTML,
+                'partpartiallycorrectfb' => self::DEFAULT_PARTIALLYCORRECT_FEEDBACK,
+                'partpartiallycorrectfbformat' => FORMAT_HTML,
+                'partincorrectfb' => self::DEFAULT_INCORRECT_FEEDBACK,
+                'partincorrectfbformat' => FORMAT_HTML,
+                'partindex' => 0,
+            ],
+        ];
+
+        $qdata->options->numpart = 1;
+
+        $qdata->hints = [
+            (object) [
+                'id' => '101',
+                'hint' => 'Hint 1.',
+                'hintformat' => FORMAT_HTML,
+                'shownumcorrect' => 1,
+                'clearwrong' => 0,
+                'options' => 0,
+            ],
+            (object) [
+                'id' => '102',
+                'hint' => 'Hint 2.',
+                'hintformat' => FORMAT_HTML,
+                'shownumcorrect' => 1,
+                'clearwrong' => 1,
+                'options' => 1,
+            ],
+        ];
+
+        return $qdata;
+    }
+
+    /**
+     * Return Formulas question with one part, one number with unit (combined), answer = 5 m/s.
+     *
+     * @return qtype_formulas_question
+     */
+    public static function make_formulas_question_testsinglenumunit(): qtype_formulas_question {
         $q = self::make_a_formulas_question();
 
-        $q->name = 'test-0';
+        $q->name = 'test-singlenumunit';
         $q->questiontext = '<p>One part, one number plus unit, answer is 5 m/s</p>';
 
         $q->penalty = 0.3;
-        $q->textfragments = array(0 => '<p>One part, one number plus unit, answer is 5 m/s</p>',
-                                  1 => '');
+        $q->textfragments = [0 => '<p>One part, one number plus unit, answer is 5 m/s</p>',
+                                  1 => ''];
         $q->numpart = 1;
         $q->defaultmark = 2;
         $p = self::make_a_formulas_part();
         $p->id = 14;
+        $p->questionid = $q->id;
         $p->placeholder = '';
         $p->answermark = 2;
         $p->answer = '5';
         $p->answernotunique = '1';
         $p->postunit = 'm/s';
         $p->subqtext = '{_0}{_u}';
-        $p->partcorrectfb = 'Your answer is correct.';
-        $p->partpartiallycorrectfb = 'Your answer is partially correct.';
-        $p->partincorrectfb = 'Your answer is incorrect.';
+
         $q->parts[0] = $p;
         return $q;
     }
@@ -323,7 +433,7 @@ public static function make_formulas_question_testsinglenumunit() {
     public function get_formulas_question_form_data_testsinglenumunit() {
         $form = new stdClass();
 
-        $form->name = 'test-0';
+        $form->name = 'test-singlenumunit';
         $form->noanswers = 1;
         $form->answer = ['5'];
         $form->answernotunique = ['1'];
@@ -372,30 +482,104 @@ public function get_formulas_question_form_data_testsinglenumunit() {
     }
 
     /**
-     * @return qtype_formulas_question one part, one number plus unit
+     * Get question data for the testsinglenumunit question.
+     *
+     * @return stdClass
      */
-    public static function make_formulas_question_testsinglenumunitsep() {
+    public static function get_formulas_question_data_testsinglenumunit(): stdClass {
+        $qdata = new stdClass();
+        test_question_maker::initialise_question_data($qdata);
+
+        $qdata->qtype = 'formulas';
+        $qdata->name = 'test-singlenumunit';
+        $qdata->questiontext = '<p>One part, one number plus unit, answer is 5 m/s</p>';
+        $qdata->generalfeedback = '';
+        $qdata->defaultmark = 2;
+        $qdata->penalty = 0.3;
+
+        $qdata->options = new stdClass();
+        $qdata->contextid = context_system::instance()->id;
+        $qdata->options->varsrandom = '';
+        $qdata->options->varsglobal = '';
+        $qdata->options->answernumbering = 'abc';
+        $qdata->options->shownumcorrect = 1;
+        $qdata->options->correctfeedback =
+                test_question_maker::STANDARD_OVERALL_CORRECT_FEEDBACK;
+        $qdata->options->correctfeedbackformat = FORMAT_HTML;
+        $qdata->options->partiallycorrectfeedback =
+                test_question_maker::STANDARD_OVERALL_PARTIALLYCORRECT_FEEDBACK;
+        $qdata->options->partiallycorrectfeedbackformat = FORMAT_HTML;
+        $qdata->options->incorrectfeedback =
+                test_question_maker::STANDARD_OVERALL_INCORRECT_FEEDBACK;
+        $qdata->options->incorrectfeedbackformat = FORMAT_HTML;
+
+        $qdata->options->answers = [
+            14 => (object) [
+                'id' => 14,
+                'questionid' => $qdata->id,
+                'placeholder' => '',
+                'answermark' => 2,
+                'answertype' => '0',
+                'numbox' => 1,
+                'vars1' => '',
+                'vars2' => '',
+                'answer' => '5',
+                'answernotunique' => '1',
+                'correctness' => '_relerr < 0.01',
+                'unitpenalty' => 1,
+                'postunit' => 'm/s',
+                'ruleid' => 1,
+                'otherrule' => '',
+                'subqtext' => '{_0}{_u}',
+                'subqtextformat' => FORMAT_HTML,
+                'feedback' => '',
+                'feedbackformat' => FORMAT_HTML,
+                'partcorrectfb' => self::DEFAULT_CORRECT_FEEDBACK,
+                'partcorrectfbformat' => FORMAT_HTML,
+                'partpartiallycorrectfb' => self::DEFAULT_PARTIALLYCORRECT_FEEDBACK,
+                'partpartiallycorrectfbformat' => FORMAT_HTML,
+                'partincorrectfb' => self::DEFAULT_INCORRECT_FEEDBACK,
+                'partincorrectfbformat' => FORMAT_HTML,
+                'partindex' => 0,
+            ],
+        ];
+
+        $qdata->options->numpart = 1;
+
+        return $qdata;
+    }
+
+    /**
+     * Return Formulas question with one part, one number with unit (separate), answer = 5 m/s.
+     *
+     * @return qtype_formulas_question
+     */
+    public static function make_formulas_question_testsinglenumunitsep(): qtype_formulas_question {
         $q = self::make_a_formulas_question();
 
-        $q->name = 'test-0';
+        $q->name = 'test-singlenumunitsep';
         $q->questiontext = '<p>One part, one number plus unit, answer is 5 m/s</p>';
 
         $q->penalty = 0.3;
-        $q->textfragments = array(0 => '<p>One part, one number plus unit, answer is 5 m/s</p>',
-                                  1 => '');
+        $q->textfragments = [
+            0 => '<p>One part, one number plus unit, answer is 5 m/s</p>',
+            1 => '',
+        ];
         $q->numpart = 1;
         $q->defaultmark = 2;
+
         $p = self::make_a_formulas_part();
         $p->id = 14;
+        $p->questionid = $q->id;
         $p->placeholder = '';
         $p->answermark = 2;
         $p->answer = '5';
         $p->answernotunique = '1';
         $p->postunit = 'm/s';
         $p->subqtext = '{_0} {_u}';
-        $p->partcorrectfb = 'Your answer is correct.';
-        $p->partpartiallycorrectfb = 'Your answer is partially correct.';
-        $p->partincorrectfb = 'Your answer is incorrect.';
+        $p->partcorrectfb = self::DEFAULT_CORRECT_FEEDBACK;
+        $p->partpartiallycorrectfb = self::DEFAULT_PARTIALLYCORRECT_FEEDBACK;
+        $p->partincorrectfb = self::DEFAULT_INCORRECT_FEEDBACK;
         $q->parts[0] = $p;
         return $q;
     }
@@ -409,37 +593,37 @@ public function get_formulas_question_form_data_testsinglenumunitsep() {
 
         $form->name = 'test-singlenumunitsep';
         $form->noanswers = 1;
-        $form->answer = array('5');
-        $form->answernotunique = array('1');
-        $form->answermark = array(2);
-        $form->answertype = array(0);
-        $form->correctness = array('_relerr < 0.01');
-        $form->numbox = array(1);
-        $form->placeholder = array('');
-        $form->vars1 = array('');
-        $form->vars2 = array('');
-        $form->ruleid = array(1);
-        $form->unitpenalty = array(1);
-        $form->postunit = array('m/s');
-        $form->otherrule = array('');
-        $form->subqtext = array(
-            array('text' => '{_0} {_u}', 'format' => FORMAT_HTML)
-        );
-        $form->feedback = array(
-            array('text' => '', 'format' => FORMAT_HTML)
-        );
-        $form->partcorrectfb = array(
-            array('text' => 'Your answer is correct.', 'format' => FORMAT_HTML)
-        );
-        $form->partpartiallycorrectfb = array(
-            array('text' => 'Your answer is partially correct.', 'format' => FORMAT_HTML)
-        );
-        $form->partincorrectfb = array(
-            array('text' => 'Your answer is incorrect.', 'format' => FORMAT_HTML)
-        );
-        $form->questiontext = array('text' => '<p>One part, one number plus unit, answer is 5 m/s</p>',
-                'format' => FORMAT_HTML);
-        $form->generalfeedback = array('text' => '', 'format' => FORMAT_HTML);
+        $form->answer = ['5'];
+        $form->answernotunique = ['1'];
+        $form->answermark = [2];
+        $form->answertype = ['0'];
+        $form->correctness = ['_relerr < 0.01'];
+        $form->numbox = [1];
+        $form->placeholder = [''];
+        $form->vars1 = [''];
+        $form->vars2 = [''];
+        $form->postunit = ['m/s'];
+        $form->otherrule = [''];
+        $form->subqtext = [
+            ['text' => '{_0} {_u}', 'format' => FORMAT_HTML],
+        ];
+        $form->feedback = [
+            ['text' => '', 'format' => FORMAT_HTML],
+        ];
+        $form->partcorrectfb = [
+            ['text' => self::DEFAULT_CORRECT_FEEDBACK, 'format' => FORMAT_HTML],
+        ];
+        $form->partpartiallycorrectfb = [
+            ['text' => self::DEFAULT_PARTIALLYCORRECT_FEEDBACK, 'format' => FORMAT_HTML],
+        ];
+        $form->partincorrectfb = [
+            ['text' => self::DEFAULT_INCORRECT_FEEDBACK, 'format' => FORMAT_HTML],
+        ];
+        $form->questiontext = [
+            'text' => '<p>One part, one number plus unit, answer is 5 m/s</p>',
+            'format' => FORMAT_HTML,
+        ];
+        $form->generalfeedback = ['text' => '', 'format' => FORMAT_HTML];
         $form->defaultmark = 2;
         $form->penalty = 0.3;
         $form->varsrandom = '';
@@ -458,21 +642,92 @@ public function get_formulas_question_form_data_testsinglenumunitsep() {
     }
 
     /**
-     * @return qtype_formulas_question question, single part, one number as answer, no unit
+     * Return question data for the testsinglenumunitsep question.
+     *
+     * @return stdClass
+     */
+    public static function get_formulas_question_data_testsinglenumunitsep(): stdClass {
+        $qdata = new stdClass();
+        test_question_maker::initialise_question_data($qdata);
+
+        $qdata->qtype = 'formulas';
+        $qdata->name = 'test-singlenumunitsep';
+        $qdata->questiontext = '<p>One part, one number plus unit, answer is 5 m/s</p>';
+        $qdata->generalfeedback = '';
+        $qdata->defaultmark = 2;
+        $qdata->penalty = 0.3;
+
+        $qdata->options = new stdClass();
+        $qdata->contextid = context_system::instance()->id;
+        $qdata->options->varsrandom = '';
+        $qdata->options->varsglobal = '';
+        $qdata->options->answernumbering = 'abc';
+        $qdata->options->shownumcorrect = 1;
+        $qdata->options->correctfeedback = test_question_maker::STANDARD_OVERALL_CORRECT_FEEDBACK;
+        $qdata->options->correctfeedbackformat = FORMAT_HTML;
+        $qdata->options->partiallycorrectfeedback = test_question_maker::STANDARD_OVERALL_PARTIALLYCORRECT_FEEDBACK;
+        $qdata->options->partiallycorrectfeedbackformat = FORMAT_HTML;
+        $qdata->options->incorrectfeedback = test_question_maker::STANDARD_OVERALL_INCORRECT_FEEDBACK;
+        $qdata->options->incorrectfeedbackformat = FORMAT_HTML;
+
+        $qdata->options->answers = [
+            14 => (object)[
+                'id' => 14,
+                'questionid' => $qdata->id,
+                'placeholder' => '',
+                'answermark' => 2,
+                'answertype' => '0',
+                'numbox' => 1,
+                'vars1' => '',
+                'vars2' => '',
+                'answer' => '5',
+                'answernotunique' => '1',
+                'correctness' => '_relerr < 0.01',
+                'unitpenalty' => 1,
+                'postunit' => 'm/s',
+                'ruleid' => 1,
+                'otherrule' => '',
+                'subqtext' => '{_0} {_u}',
+                'subqtextformat' => FORMAT_HTML,
+                'feedback' => '',
+                'feedbackformat' => FORMAT_HTML,
+                'partcorrectfb' => self::DEFAULT_CORRECT_FEEDBACK,
+                'partcorrectfbformat' => FORMAT_HTML,
+                'partpartiallycorrectfb' => self::DEFAULT_PARTIALLYCORRECT_FEEDBACK,
+                'partpartiallycorrectfbformat' => FORMAT_HTML,
+                'partincorrectfb' => self::DEFAULT_INCORRECT_FEEDBACK,
+                'partincorrectfbformat' => FORMAT_HTML,
+                'partindex' => 0,
+            ],
+        ];
+
+        $qdata->options->numpart = 1;
+
+        return $qdata;
+    }
+
+    /**
+     * Return Formulas question: one part, two numbers, answer = 2 and 3.
+     *
+     * @return qtype_formulas_question
      */
-    public static function make_formulas_question_testtwonums() {
+    public static function make_formulas_question_testtwonums(): qtype_formulas_question {
         $q = self::make_a_formulas_question();
 
         $q->name = 'test-1';
         $q->questiontext = '<p>Question with two numbers. The answers are 2 and 3.</p>';
 
         $q->penalty = 0.3; // Non-zero and not the default.
-        $q->textfragments = array(0 => '<p>Question with two numbers. The answers are 2 and 3.</p>',
-                                  1 => '');
+        $q->textfragments = [
+            0 => '<p>Question with two numbers. The answers are 2 and 3.</p>',
+            1 => '',
+        ];
         $q->numpart = 1;
         $q->defaultmark = 2;
+
         $p = self::make_a_formulas_part();
         $p->id = 14;
+        $p->questionid = $q->id;
         $p->placeholder = '';
         $p->answermark = 2;
         $p->answer = '[2, 3]';
@@ -542,19 +797,20 @@ public function get_formulas_question_form_data_testtwonums() {
     }
 
     /**
+     * Return Formulas question with 3 parts, not randomised, answers = 5, 6, 7.
+     *
      * @return qtype_formulas_question with 3 parts.
-     * this version is non randomized to ease testing
      */
-    public static function make_formulas_question_testthreeparts() {
+    public static function make_formulas_question_testthreeparts(): qtype_formulas_question {
         $q = self::make_a_formulas_question();
 
         $q->name = 'test-1';
         $q->questiontext = '<p>Multiple parts : --{#1}--{#2}--{#3}</p>';
         $q->penalty = 0.3; // Non-zero and not the default.
-        $q->textfragments = array(0 => '<p>Multiple parts : --',
+        $q->textfragments = [0 => '<p>Multiple parts : --',
                 1 => '--',
                 2 => '--',
-                3 => '</p>');
+                3 => '</p>'];
         $q->numpart = 3;
         $q->defaultmark = 6;
         $p0 = self::make_a_formulas_part();
@@ -604,28 +860,26 @@ public function get_formulas_question_form_data_testthreeparts() {
         $form = new stdClass();
 
         $form->name = 'test-1';
-        $form->questiontext = array('text' => '<p>Multiple parts : --{#1}--{#2}--{#3}</p>',
-                'format' => FORMAT_HTML);
-        $form->generalfeedback = array('text' => '', 'format' => FORMAT_HTML);
+        $form->questiontext = ['text' => '<p>Multiple parts : --{#1}--{#2}--{#3}</p>',
+                'format' => FORMAT_HTML];
+        $form->generalfeedback = ['text' => '', 'format' => FORMAT_HTML];
         $form->defaultmark = 6;
         $form->penalty = 0.3;
         $form->varsrandom = '';
         $form->varsglobal = '';
         $form->answernumbering = 'abc';
         $form->noanswers = 3;
-        $form->answer = array('5', '6', '7');
-        $form->answernotunique = array('1', '1', '1');
-        $form->answermark = array('2', '2', '2');
-        $form->numbox = array(1, 1, 1);
-        $form->placeholder = array('#1', '#2', '#3');
-        $form->postunit = array('', '', '');
-        $form->answertype = array(0, 0, 0);
-        $form->vars1 = array('', '', '');
-        $form->correctness = array('_relerr < 0.01', '_relerr < 0.01', '_relerr < 0.01');
-        $form->vars2 = array('', '', '');
-        $form->unitpenalty = array(1, 1, 1);
-        $form->ruleid = array('1', '1', '1');
-        $form->otherrule = array('', '', '');
+        $form->answer = ['5', '6', '7'];
+        $form->answernotunique = ['1', '1', '1'];
+        $form->answermark = ['2', '2', '2'];
+        $form->numbox = [1, 1, 1];
+        $form->placeholder = ['#1', '#2', '#3'];
+        $form->postunit = ['', '', ''];
+        $form->answertype = ['0', '0', '0'];
+        $form->vars1 = ['', '', ''];
+        $form->correctness = ['_relerr < 0.01', '_relerr < 0.01', '_relerr < 0.01'];
+        $form->vars2 = ['', '', ''];
+        $form->otherrule = ['', '', ''];
         $form->globalunitpenalty = 1;
         $form->globalruleid = 1;
         $form->subqtext = [
@@ -661,23 +915,24 @@ public function get_formulas_question_form_data_testthreeparts() {
         $form->shownumcorrect = '0';
         $form->incorrectfeedback = ['text' => 'That is not right at all.', 'format' => FORMAT_HTML];
         $form->numhints = 2;
-        $form->hint = array(
-            array('text' => '', 'format' => FORMAT_HTML),
-            array('text' => '', 'format' => FORMAT_HTML),
-        );
-        $form->hintclearwrong = array('0', '0');
-        $form->hintshownumcorrect = array('0', '0');
+        $form->hint = [
+            ['text' => '', 'format' => FORMAT_HTML],
+            ['text' => '', 'format' => FORMAT_HTML],
+        ];
+        $form->hintclearwrong = ['0', '0'];
+        $form->hintshownumcorrect = ['0', '0'];
         return $form;
     }
 
     /**
-     * @return qtype_formulas_question the question from the test1.xml file.
-     * Non randomized version for Behat tests.
+     * Return Formulas question with 4 parts, not randomised, separate and combined unit fields.
+     *
+     * @return qtype_formulas_question
      */
-    public static function make_formulas_question_testmethodsinparts() {
+    public static function make_formulas_question_testmethodsinparts(): qtype_formulas_question {
         $q = self::make_a_formulas_question();
 
-        $q->name = 'test-2';
+        $q->name = 'test-methodsinparts';
         $q->questiontext = '<p>This question shows different display methods of the answer and unit box.</p>';
         $q->defaultmark = 8;
         $q->penalty = 0.3; // Non-zero and not the default.
@@ -688,10 +943,12 @@ public static function make_formulas_question_testmethodsinparts() {
                 2 => '',
                 3 => '',
                 4 => '',
-                );
+                ];
         $q->varsrandom = '';
         $q->varsglobal = 'v = 40;dt = 3;s = v*dt;';
+
         $p0 = self::make_a_formulas_part();
+        $p0->questionid = $q->id;
         $p0->id = 14;
         $p0->partindex = 0;
         $p0->answermark = 2;
@@ -700,7 +957,9 @@ public static function make_formulas_question_testmethodsinparts() {
         $p0->answernotunique = '1';
         $p0->postunit = 'm/s';
         $q->parts[0] = $p0;
+
         $p1 = self::make_a_formulas_part();
+        $p1->questionid = $q->id;
         $p1->id = 15;
         $p1->partindex = 1;
         $p1->answermark = 2;
@@ -709,7 +968,9 @@ public static function make_formulas_question_testmethodsinparts() {
         $p1->answernotunique = '1';
         $p1->postunit = 'm/s';
         $q->parts[1] = $p1;
+
         $p2 = self::make_a_formulas_part();
+        $p2->questionid = $q->id;
         $p2->id = 16;
         $p2->partindex = 2;
         $p2->answermark = 2;
@@ -719,7 +980,9 @@ public static function make_formulas_question_testmethodsinparts() {
         $p2->answernotunique = '1';
         $p2->postunit = '';
         $q->parts[2] = $p2;
+
         $p3 = self::make_a_formulas_part();
+        $p3->questionid = $q->id;
         $p3->id = 17;
         $p3->partindex = 3;
         $p3->answermark = 2;
@@ -730,6 +993,11 @@ public static function make_formulas_question_testmethodsinparts() {
         $p3->postunit = '';
         $q->parts[3] = $p3;
 
+        $q->hints = [
+            new question_hint_with_parts(101, 'Hint 1.', FORMAT_HTML, 1, 0),
+            new question_hint_with_parts(102, 'Hint 2.', FORMAT_HTML, 1, 1),
+        ];
+
         return $q;
     }
 
@@ -738,25 +1006,22 @@ public static function make_formulas_question_testmethodsinparts() {
      * @return object
      */
     public static function get_formulas_question_data_testmethodsinparts() {
-        global $USER;
-
         $qdata = new stdClass();
         test_question_maker::initialise_question_data($qdata);
 
         $qdata->qtype = 'formulas';
-        $qdata->name = 'test-2';
+        $qdata->name = 'test-methodsinparts';
         $qdata->questiontext = '<p>This question shows different display methods of the answer and unit box.</p>';
         $qdata->generalfeedback = 'This is the general feedback.';
         $qdata->defaultmark = 8;
-        $qdata->length = 1;
         $qdata->penalty = 0.3;
-        $qdata->hidden = 0;
 
         $qdata->options = new stdClass();
+        $qdata->contextid = context_system::instance()->id;
         $qdata->options->varsrandom = '';
         $qdata->options->varsglobal = 'v = 40;dt = 3;s = v*dt;';
         $qdata->options->answernumbering = 'abc';
-        $qdata->options->shownumcorrect = 0;
+        $qdata->options->shownumcorrect = 1;
         $qdata->options->correctfeedback =
                 test_question_maker::STANDARD_OVERALL_CORRECT_FEEDBACK;
         $qdata->options->correctfeedbackformat = FORMAT_HTML;
@@ -767,12 +1032,13 @@ public static function get_formulas_question_data_testmethodsinparts() {
                 test_question_maker::STANDARD_OVERALL_INCORRECT_FEEDBACK;
         $qdata->options->incorrectfeedbackformat = FORMAT_HTML;
 
-        $qdata->options->answers = array(
-            14 => (object) array(
+        $qdata->options->answers = [
+            14 => (object) [
                 'id' => 14,
+                'questionid' => $qdata->id,
                 'placeholder' => '',
                 'answermark' => 2,
-                'answertype' => 0,
+                'answertype' => '0',
                 'numbox' => 1,
                 'vars1' => '',
                 'vars2' => '',
@@ -787,19 +1053,20 @@ public static function get_formulas_question_data_testmethodsinparts() {
                 'subqtextformat' => FORMAT_HTML,
                 'feedback' => '',
                 'feedbackformat' => FORMAT_HTML,
-                'partcorrectfb' => '',
+                'partcorrectfb' => self::DEFAULT_CORRECT_FEEDBACK,
                 'partcorrectfbformat' => FORMAT_HTML,
-                'partpartiallycorrectfb' => '',
+                'partpartiallycorrectfb' => self::DEFAULT_PARTIALLYCORRECT_FEEDBACK,
                 'partpartiallycorrectfbformat' => FORMAT_HTML,
-                'partincorrectfb' => '',
+                'partincorrectfb' => self::DEFAULT_INCORRECT_FEEDBACK,
                 'partincorrectfbformat' => FORMAT_HTML,
                 'partindex' => 0,
-            ),
-            15 => (object) array(
+            ],
+            15 => (object) [
                 'id' => 15,
+                'questionid' => $qdata->id,
                 'placeholder' => '',
                 'answermark' => 2,
-                'answertype' => 0,
+                'answertype' => '0',
                 'numbox' => 1,
                 'vars1' => '',
                 'vars2' => '',
@@ -814,19 +1081,20 @@ public static function get_formulas_question_data_testmethodsinparts() {
                 'subqtextformat' => FORMAT_HTML,
                 'feedback' => '',
                 'feedbackformat' => FORMAT_HTML,
-                'partcorrectfb' => '',
+                'partcorrectfb' => self::DEFAULT_CORRECT_FEEDBACK,
                 'partcorrectfbformat' => FORMAT_HTML,
-                'partpartiallycorrectfb' => '',
+                'partpartiallycorrectfb' => self::DEFAULT_PARTIALLYCORRECT_FEEDBACK,
                 'partpartiallycorrectfbformat' => FORMAT_HTML,
-                'partincorrectfb' => '',
+                'partincorrectfb' => self::DEFAULT_INCORRECT_FEEDBACK,
                 'partincorrectfbformat' => FORMAT_HTML,
                 'partindex' => 1,
-            ),
-            16 => (object) array(
+            ],
+            16 => (object) [
                 'id' => 16,
+                'questionid' => $qdata->id,
                 'placeholder' => '',
                 'answermark' => 2,
-                'answertype' => 0,
+                'answertype' => '0',
                 'numbox' => 1,
                 'vars1' => '',
                 'vars2' => '',
@@ -841,19 +1109,20 @@ public static function get_formulas_question_data_testmethodsinparts() {
                 'subqtextformat' => FORMAT_HTML,
                 'feedback' => '',
                 'feedbackformat' => FORMAT_HTML,
-                'partcorrectfb' => '',
+                'partcorrectfb' => self::DEFAULT_CORRECT_FEEDBACK,
                 'partcorrectfbformat' => FORMAT_HTML,
-                'partpartiallycorrectfb' => '',
+                'partpartiallycorrectfb' => self::DEFAULT_PARTIALLYCORRECT_FEEDBACK,
                 'partpartiallycorrectfbformat' => FORMAT_HTML,
-                'partincorrectfb' => '',
+                'partincorrectfb' => self::DEFAULT_INCORRECT_FEEDBACK,
                 'partincorrectfbformat' => FORMAT_HTML,
                 'partindex' => 2,
-            ),
-            17 => (object) array(
+            ],
+            17 => (object) [
                 'id' => 17,
+                'questionid' => $qdata->id,
                 'placeholder' => '',
                 'answermark' => 2,
-                'answertype' => 0,
+                'answertype' => '0',
                 'numbox' => 1,
                 'vars1' => '',
                 'vars2' => '',
@@ -864,38 +1133,40 @@ public static function get_formulas_question_data_testmethodsinparts() {
                 'postunit' => '',
                 'ruleid' => 1,
                 'otherrule' => '',
-                'subqtext' => '<p>If a car travels {s} m in {dt} s, what is the speed of the car? speed = {_0}{_u}',
+                'subqtext' => '<p>If a car travels {s} m in {dt} s, what is the speed of the car? speed = {_0}{_u}</p>',
                 'subqtextformat' => FORMAT_HTML,
                 'feedback' => '',
                 'feedbackformat' => FORMAT_HTML,
-                'partcorrectfb' => '',
+                'partcorrectfb' => self::DEFAULT_CORRECT_FEEDBACK,
                 'partcorrectfbformat' => FORMAT_HTML,
-                'partpartiallycorrectfb' => '',
+                'partpartiallycorrectfb' => self::DEFAULT_PARTIALLYCORRECT_FEEDBACK,
                 'partpartiallycorrectfbformat' => FORMAT_HTML,
-                'partincorrectfb' => '',
+                'partincorrectfb' => self::DEFAULT_INCORRECT_FEEDBACK,
                 'partincorrectfbformat' => FORMAT_HTML,
                 'partindex' => 3,
-            ),
-        );
+            ],
+        ];
 
         $qdata->options->numpart = 4;
 
-        $qdata->hints = array(
-            1 => (object) array(
+        $qdata->hints = [
+            1 => (object) [
+                'id' => 101,
                 'hint' => 'Hint 1.',
                 'hintformat' => FORMAT_HTML,
                 'shownumcorrect' => 1,
                 'clearwrong' => 0,
                 'options' => 0,
-            ),
-            2 => (object) array(
+            ],
+            2 => (object) [
+                'id' => 102,
                 'hint' => 'Hint 2.',
                 'hintformat' => FORMAT_HTML,
                 'shownumcorrect' => 1,
                 'clearwrong' => 1,
                 'options' => 1,
-            ),
-        );
+            ],
+        ];
 
         return $qdata;
     }
@@ -907,142 +1178,133 @@ public static function get_formulas_question_data_testmethodsinparts() {
     public function get_formulas_question_form_data_testmethodsinparts() {
         $form = new stdClass();
 
-        $form->name = 'test-2';
-        $form->questiontext = array('text' => '<p>This question shows different display methods of the answer and unit box.</p>',
-                'format' => FORMAT_HTML);
-        $form->generalfeedback = array('text' => 'This is the general feedback.', 'format' => FORMAT_HTML);
+        $form->name = 'test-methodsinparts';
+        $form->questiontext = ['text' => '<p>This question shows different display methods of the answer and unit box.</p>',
+                'format' => FORMAT_HTML];
+        $form->generalfeedback = ['text' => 'This is the general feedback.', 'format' => FORMAT_HTML];
         $form->defaultmark = 8;
         $form->penalty = 0.3;
         $form->varsrandom = '';
         $form->varsglobal = 'v = 40;dt = 3;s = v*dt;';
         $form->answernumbering = 'abc';
         $form->noanswers = 4;
-        $form->answer = array(
+        $form->answer = [
             0 => 'v',
             1 => 'v',
             2 => 'v',
             3 => 'v',
-        );
-        $form->answernotunique = array(
+        ];
+        $form->answernotunique = [
             0 => '1',
             1 => '1',
             2 => '1',
             3 => '1',
-        );
-        $form->answermark = array(
+        ];
+        $form->answermark = [
             0 => 2,
             1 => 2,
             2 => 2,
             3 => 2,
-        );
-        $form->numbox = array(
+        ];
+        $form->numbox = [
             0 => 1,
             1 => 1,
             2 => 1,
             3 => 1,
-        );
-        $form->placeholder = array(
+        ];
+        $form->placeholder = [
             0 => '',
             1 => '',
             2 => '',
             3 => '',
-        );
-        $form->postunit = array(
+        ];
+        $form->postunit = [
             0 => 'm/s',
             1 => 'm/s',
             2 => '',
             3 => '',
-        );
-        $form->answertype = array(
-            0 => 0,
-            1 => 0,
-            2 => 0,
-            3 => 0,
-        );
-        $form->vars1 = array(
+        ];
+        $form->answertype = [
+            0 => '0',
+            1 => '0',
+            2 => '0',
+            3 => '0',
+        ];
+        $form->vars1 = [
             0 => '',
             1 => '',
             2 => '',
             3 => '',
-        );
-        $form->correctness = array(
+        ];
+        $form->correctness = [
             0 => '_relerr < 0.01',
             1 => '_relerr < 0.01',
             2 => '_relerr < 0.01',
-            3 => '_relerr < 0.01'
-        );
-        $form->vars2 = array(
+            3 => '_relerr < 0.01',
+        ];
+        $form->vars2 = [
             0 => '',
             1 => '',
             2 => '',
             3 => '',
-        );
-        $form->unitpenalty = array(
-            0 => '1.0',
-            1 => '1.0',
-            2 => '1.0',
-            3 => '1.0',
-        );
-        $form->ruleid = array(
-            0 => 1,
-            1 => 1,
-            2 => 1,
-            3 => 1,
-        );
-        $form->otherrule = array(
+        ];
+        $form->otherrule = [
             0 => '',
             1 => '',
             2 => '',
             3 => '',
-        );
+        ];
         $form->globalunitpenalty = 1;
         $form->globalruleid = 1;
-        $form->subqtext = array(
-            0 => array(
+        $form->subqtext = [
+            0 => [
               'text' => '<p>If a car travels {s} m in {dt} s, what is the speed of the car? {_0}{_u}</p>',
-              'format' => FORMAT_HTML
-            ),
-            1 => array(
+              'format' => FORMAT_HTML,
+            ],
+            1 => [
               'text' => '<p>If a car travels {s} m in {dt} s, what is the speed of the car? {_0} {_u}</p>',
-              'format' => FORMAT_HTML
-            ),
-            2 => array(
+              'format' => FORMAT_HTML,
+            ],
+            2 => [
               'text' => '<p>If a car travels {s} m in {dt} s, what is the speed of the car? {_0} {_u}</p>',
-              'format' => FORMAT_HTML
-            ),
-            3 => array(
+              'format' => FORMAT_HTML,
+            ],
+            3 => [
               'text' => '<p>If a car travels {s} m in {dt} s, what is the speed of the car? speed = {_0}{_u}</p>',
-              'format' => FORMAT_HTML
-            ),
-        );
-        $form->feedback = array(
-            0 => array('text' => '', 'format' => FORMAT_HTML),
-            1 => array('text' => '', 'format' => FORMAT_HTML),
-            2 => array('text' => '', 'format' => FORMAT_HTML),
-            3 => array('text' => '', 'format' => FORMAT_HTML),
-        );
-        $form->partcorrectfb = array(
-            0 => array('text' => '', 'format' => FORMAT_HTML),
-            1 => array('text' => '', 'format' => FORMAT_HTML),
-            2 => array('text' => '', 'format' => FORMAT_HTML),
-            3 => array('text' => '', 'format' => FORMAT_HTML),
-        );
-        $form->partpartiallycorrectfb = array(
-            0 => array('text' => '', 'format' => FORMAT_HTML),
-            1 => array('text' => '', 'format' => FORMAT_HTML),
-            2 => array('text' => '', 'format' => FORMAT_HTML),
-            3 => array('text' => '', 'format' => FORMAT_HTML),
-        );
-        $form->partincorrectfb = array(
-            0 => array('text' => '', 'format' => FORMAT_HTML),
-            1 => array('text' => '', 'format' => FORMAT_HTML),
-            2 => array('text' => '', 'format' => FORMAT_HTML),
-            3 => array('text' => '', 'format' => FORMAT_HTML),
-        );
-        $form->correctfeedback = array('text' => '', 'format' => FORMAT_HTML);
-        $form->partiallycorrectfeedback = array('text' => '', 'format' => FORMAT_HTML);
-        $form->shownumcorrect = '0';
-        $form->incorrectfeedback = array('text' => '', 'format' => FORMAT_HTML);
+              'format' => FORMAT_HTML,
+            ],
+        ];
+        $form->feedback = [
+            0 => ['text' => '', 'format' => FORMAT_HTML],
+            1 => ['text' => '', 'format' => FORMAT_HTML],
+            2 => ['text' => '', 'format' => FORMAT_HTML],
+            3 => ['text' => '', 'format' => FORMAT_HTML],
+        ];
+        $form->partcorrectfb = [
+            0 => ['text' => self::DEFAULT_CORRECT_FEEDBACK, 'format' => FORMAT_HTML],
+            1 => ['text' => self::DEFAULT_CORRECT_FEEDBACK, 'format' => FORMAT_HTML],
+            2 => ['text' => self::DEFAULT_CORRECT_FEEDBACK, 'format' => FORMAT_HTML],
+            3 => ['text' => self::DEFAULT_CORRECT_FEEDBACK, 'format' => FORMAT_HTML],
+        ];
+        $form->partpartiallycorrectfb = [
+            0 => ['text' => self::DEFAULT_PARTIALLYCORRECT_FEEDBACK, 'format' => FORMAT_HTML],
+            1 => ['text' => self::DEFAULT_PARTIALLYCORRECT_FEEDBACK, 'format' => FORMAT_HTML],
+            2 => ['text' => self::DEFAULT_PARTIALLYCORRECT_FEEDBACK, 'format' => FORMAT_HTML],
+            3 => ['text' => self::DEFAULT_PARTIALLYCORRECT_FEEDBACK, 'format' => FORMAT_HTML],
+        ];
+        $form->partincorrectfb = [
+            0 => ['text' => self::DEFAULT_INCORRECT_FEEDBACK, 'format' => FORMAT_HTML],
+            1 => ['text' => self::DEFAULT_INCORRECT_FEEDBACK, 'format' => FORMAT_HTML],
+            2 => ['text' => self::DEFAULT_INCORRECT_FEEDBACK, 'format' => FORMAT_HTML],
+            3 => ['text' => self::DEFAULT_INCORRECT_FEEDBACK, 'format' => FORMAT_HTML],
+        ];
+        $form->correctfeedback = ['text' => test_question_maker::STANDARD_OVERALL_CORRECT_FEEDBACK, 'format' => FORMAT_HTML];
+        $form->partiallycorrectfeedback = [
+            'text' => test_question_maker::STANDARD_OVERALL_PARTIALLYCORRECT_FEEDBACK,
+            'format' => FORMAT_HTML,
+        ];
+        $form->incorrectfeedback = ['text' => test_question_maker::STANDARD_OVERALL_INCORRECT_FEEDBACK, 'format' => FORMAT_HTML];
+        $form->shownumcorrect = '1';
         $form->numhints = 2;
         $form->hint = [
             ['text' => 'Hint 1.', 'format' => FORMAT_HTML],
@@ -1054,17 +1316,19 @@ public function get_formulas_question_form_data_testmethodsinparts() {
     }
 
     /**
-     * @return qtype_formulas_question the question with 0 as answer.
+     * Return Formulas question with one part, not randomized, answer = 0, used to test for problems with 0 as answer.
+     *
+     * @return qtype_formulas_question
      */
-    public static function make_formulas_question_testzero() {
+    public static function make_formulas_question_testzero(): qtype_formulas_question {
         $q = self::make_a_formulas_question();
 
         $q->name = 'test-3';
         $q->questiontext = '<p>This question has 0 as answer to test problem when answer is equal to 0.</p>';
 
         $q->penalty = 0.3; // Non-zero and not the default.
-        $q->textfragments = array(0 => '<p>This question has 0 as answer to test problem when answer is equal to 0.</p>',
-                1 => '');
+        $q->textfragments = [0 => '<p>This question has 0 as answer to test problem when answer is equal to 0.</p>',
+                1 => ''];
         $q->numpart = 1;
         $q->defaultmark = 2;
         $p = self::make_a_formulas_part();
@@ -1086,37 +1350,35 @@ public function get_formulas_question_form_data_testzero() {
 
         $form->name = 'test-3';
         $form->noanswers = 1;
-        $form->answer = array('0');
-        $form->answernotunique = array('1');
-        $form->answermark = array(2);
-        $form->answertype = array(0);
-        $form->correctness = array('_relerr < 0.01');
-        $form->numbox = array(1);
-        $form->placeholder = array('');
-        $form->vars1 = array('');
-        $form->vars2 = array('');
-        $form->ruleid = array(1);
-        $form->unitpenalty = array(1);
-        $form->postunit = array('');
-        $form->otherrule = array('');
-        $form->subqtext = array(
-            array('text' => '', 'format' => FORMAT_HTML)
-        );
-        $form->feedback = array(
-            array('text' => '', 'format' => FORMAT_HTML)
-        );
-        $form->partcorrectfb = array(
-            array('text' => 'Your answer is correct.', 'format' => FORMAT_HTML)
-        );
-        $form->partpartiallycorrectfb = array(
-            array('text' => 'Your answer is partially correct.', 'format' => FORMAT_HTML)
-        );
-        $form->partincorrectfb = array(
-            array('text' => 'Your answer is incorrect.', 'format' => FORMAT_HTML)
-        );
-        $form->questiontext = array('text' => '<p>This question has 0 as answer to test problem when answer is equal to 0.</p>',
-                'format' => FORMAT_HTML);
-        $form->generalfeedback = array('text' => '', 'format' => FORMAT_HTML);
+        $form->answer = ['0'];
+        $form->answernotunique = ['1'];
+        $form->answermark = [2];
+        $form->answertype = ['0'];
+        $form->correctness = ['_relerr < 0.01'];
+        $form->numbox = [1];
+        $form->placeholder = [''];
+        $form->vars1 = [''];
+        $form->vars2 = [''];
+        $form->postunit = [''];
+        $form->otherrule = [''];
+        $form->subqtext = [
+            ['text' => '', 'format' => FORMAT_HTML],
+        ];
+        $form->feedback = [
+            ['text' => '', 'format' => FORMAT_HTML],
+        ];
+        $form->partcorrectfb = [
+            ['text' => self::DEFAULT_CORRECT_FEEDBACK, 'format' => FORMAT_HTML],
+        ];
+        $form->partpartiallycorrectfb = [
+            ['text' => self::DEFAULT_PARTIALLYCORRECT_FEEDBACK, 'format' => FORMAT_HTML],
+        ];
+        $form->partincorrectfb = [
+            ['text' => self::DEFAULT_INCORRECT_FEEDBACK, 'format' => FORMAT_HTML],
+        ];
+        $form->questiontext = ['text' => '<p>This question has 0 as answer to test problem when answer is equal to 0.</p>',
+                'format' => FORMAT_HTML];
+        $form->generalfeedback = ['text' => '', 'format' => FORMAT_HTML];
         $form->defaultmark = 2;
         $form->penalty = 0.3;
         $form->varsrandom = '';
@@ -1124,18 +1386,22 @@ public function get_formulas_question_form_data_testzero() {
         $form->answernumbering = '';
         $form->globalunitpenalty = 1;
         $form->globalruleid = 1;
-        $form->correctfeedback = array('text' => '', 'format' => FORMAT_HTML);
-        $form->partiallycorrectfeedback = array('text' => '', 'format' => FORMAT_HTML);
+        $form->correctfeedback = ['text' => 'Well done!', 'format' => FORMAT_HTML];
+        $form->partiallycorrectfeedback = [
+            'text' => 'Parts, but only parts, of your response are correct.',
+            'format' => FORMAT_HTML,
+        ];
         $form->shownumcorrect = '0';
-        $form->incorrectfeedback = array('text' => '', 'format' => FORMAT_HTML);
+        $form->incorrectfeedback = ['text' => 'That is not right at all.', 'format' => FORMAT_HTML];
         return $form;
     }
 
     /**
-     * @return qtype_formulas_question the question from the test1.xml file.
-     * Randomized version.
+     * Return Formulas question with 4 parts, randomised, separate and combined unit fields.
+     *
+     * @return qtype_formulas_question
      */
-    public static function make_formulas_question_test4() {
+    public static function make_formulas_question_test4(): qtype_formulas_question {
         $q = self::make_a_formulas_question();
 
         $q->name = 'test-4';
@@ -1149,7 +1415,7 @@ public static function make_formulas_question_test4() {
                 2 => '',
                 3 => '',
                 4 => '',
-                );
+                ];
         $q->varsrandom = 'v = {20:100:10}; dt = {2:6};';
         $q->varsglobal = 's = v*dt;';
         $p0 = self::make_a_formulas_part();
@@ -1202,44 +1468,42 @@ public function get_formulas_question_form_data_test4() {
         $form = new stdClass();
 
         $form->name = 'test-4';
-        $form->questiontext = array('text' => '<p>This question shows different display methods of the answer and unit box.</p>',
-                'format' => FORMAT_HTML);
-        $form->generalfeedback = array('text' => 'This is the general feedback.', 'format' => FORMAT_HTML);
+        $form->questiontext = ['text' => '<p>This question shows different display methods of the answer and unit box.</p>',
+                'format' => FORMAT_HTML];
+        $form->generalfeedback = ['text' => 'This is the general feedback.', 'format' => FORMAT_HTML];
         $form->defaultmark = 8;
         $form->penalty = 0.3;
         $form->varsrandom = 'v = {20:100:10}; dt = {2:6};';
         $form->varsglobal = 's = v*dt;';
         $form->answernumbering = 'abc';
         $form->noanswers = 4;
-        $form->answer = array('v', 'v', 'v', 'v');
-        $form->answernotunique = array('1', '1', '1', '1');
-        $form->answermark = array('2', '2', '2', '2');
-        $form->numbox = array(1, 1, 1, 1);
-        $form->placeholder = array('', '', '', '');
-        $form->postunit = array('m/s', 'm/s', '', '');
-        $form->answertype = array(0, 0, 0, 0);
-        $form->vars1 = array('', '', '', '');
-        $form->correctness = array('_relerr < 0.01', '_relerr < 0.01', '_relerr < 0.01', '_relerr < 0.01');
-        $form->vars2 = array('', '', '', '');
-        $form->unitpenalty = array(1, 1, 1, 1);
-        $form->ruleid = array('1', '1', '1', '1');
-        $form->otherrule = array('', '', '', '');
+        $form->answer = ['v', 'v', 'v', 'v'];
+        $form->answernotunique = ['1', '1', '1', '1'];
+        $form->answermark = ['2', '2', '2', '2'];
+        $form->numbox = [1, 1, 1, 1];
+        $form->placeholder = ['', '', '', ''];
+        $form->postunit = ['m/s', 'm/s', '', ''];
+        $form->answertype = ['0', '0', '0', '0'];
+        $form->vars1 = ['', '', '', ''];
+        $form->correctness = ['_relerr < 0.01', '_relerr < 0.01', '_relerr < 0.01', '_relerr < 0.01'];
+        $form->vars2 = ['', '', '', ''];
+        $form->otherrule = ['', '', '', ''];
         $form->globalunitpenalty = 1;
         $form->globalruleid = 1;
-        $form->subqtext = array(
-            array(
+        $form->subqtext = [
+            [
               'text' => '<p>If a car travels {s} m in {dt} s, what is the speed of the car? {_0}{_u}</p>',
-              'format' => FORMAT_HTML
-            ),
-            array(
+              'format' => FORMAT_HTML,
+            ],
+            [
               'text' => '<p>If a car travels {s} m in {dt} s, what is the speed of the car? {_0} {_u}</p>',
-              'format' => FORMAT_HTML
-            ),
-            array(
+              'format' => FORMAT_HTML,
+            ],
+            [
               'text' => '<p>If a car travels {s} m in {dt} s, what is the speed of the car? {_0} {_u}</p>',
-              'format' => FORMAT_HTML
-            ),
-            array(
+              'format' => FORMAT_HTML,
+            ],
+            [
               'text' => '<p>If a car travels {s} m in {dt} s, what is the speed of the car? speed = {_0}{_u}</p>',
               'format' => FORMAT_HTML,
             ],
@@ -1276,35 +1540,37 @@ public function get_formulas_question_form_data_test4() {
         $form->shownumcorrect = '0';
         $form->incorrectfeedback = ['text' => 'That is not right at all.', 'format' => FORMAT_HTML];
         $form->numhints = 2;
-        $form->hint = array(
-            array('text' => '', 'format' => FORMAT_HTML),
-            array('text' => '', 'format' => FORMAT_HTML),
-        );
-        $form->hintclearwrong = array('0', '0');
-        $form->hintshownumcorrect = array('0', '0');
+        $form->hint = [
+            ['text' => '', 'format' => FORMAT_HTML],
+            ['text' => '', 'format' => FORMAT_HTML],
+        ];
+        $form->hintclearwrong = ['0', '0'];
+        $form->hintshownumcorrect = ['0', '0'];
         return $form;
     }
 
     /**
-     * @return qtype_formulas_question with a (radio button) multichoice answer.
+     * Return Formulas question with one part, not randomized, radio button multichoice answer.
+     *
+     * @return qtype_formulas_question
      */
-    public static function make_formulas_question_testmc() {
+    public static function make_formulas_question_testmc(): qtype_formulas_question {
         $q = self::make_a_formulas_question();
 
         $q->name = 'test-5';
         $q->questiontext = '<p>This question has a multichoice answer.</p>';
         $q->varsglobal = 'mychoices=["Dog","Cat","Bird","Fish"];';
         $q->penalty = 0.3; // Non-zero and not the default.
-        $q->textfragments = array(0 => '<p>This question has a multichoice answer.</p>',
-                                  1 => '');
+        $q->textfragments = [0 => '<p>This question has a multichoice answer.</p>',
+                                  1 => ''];
         $q->numpart = 1;
         $q->defaultmark = 2;
         $p = self::make_a_formulas_part();
         $p->id = 14;
-        $p->answermark = 1;
+        $p->answermark = 2;
         $p->answer = '1';
         $p->answernotunique = '1';
-        $p->subqtext = '{_0:mychoices:MC}';
+        $p->subqtext = '{_0:mychoices}';
         $q->parts[0] = $p;
 
         return $q;
@@ -1319,37 +1585,35 @@ public function get_formulas_question_form_data_testmc() {
 
         $form->name = 'test-5';
         $form->noanswers = 1;
-        $form->answer = array('1');
-        $form->answernotunique = array('1');
-        $form->answermark = array(1);
-        $form->answertype = array(0);
-        $form->correctness = array('_relerr < 0.01');
-        $form->numbox = array(1);
-        $form->placeholder = array('');
-        $form->vars1 = array('');
-        $form->vars2 = array('');
-        $form->ruleid = array(1);
-        $form->unitpenalty = array(1);
-        $form->postunit = array('');
-        $form->otherrule = array('');
-        $form->subqtext = array(
-            array('text' => '{_0:mychoices:MC}', 'format' => FORMAT_HTML)
-        );
-        $form->feedback = array(
-            array('text' => '', 'format' => FORMAT_HTML)
-        );
-        $form->partcorrectfb = array(
-            array('text' => 'Your answer is correct.', 'format' => FORMAT_HTML)
-        );
-        $form->partpartiallycorrectfb = array(
-            array('text' => 'Your answer is partially correct.', 'format' => FORMAT_HTML)
-        );
-        $form->partincorrectfb = array(
-            array('text' => 'Your answer is incorrect.', 'format' => FORMAT_HTML)
-        );
-        $form->questiontext = array('text' => '<p>This question has a multichoice answer.</p>',
-                'format' => FORMAT_HTML);
-        $form->generalfeedback = array('text' => '', 'format' => FORMAT_HTML);
+        $form->answer = ['1'];
+        $form->answernotunique = ['1'];
+        $form->answermark = [2];
+        $form->answertype = ['0'];
+        $form->correctness = ['_relerr < 0.01'];
+        $form->numbox = [1];
+        $form->placeholder = [''];
+        $form->vars1 = [''];
+        $form->vars2 = [''];
+        $form->postunit = [''];
+        $form->otherrule = [''];
+        $form->subqtext = [
+            ['text' => '{_0:mychoices}', 'format' => FORMAT_HTML],
+        ];
+        $form->feedback = [
+            ['text' => '', 'format' => FORMAT_HTML],
+        ];
+        $form->partcorrectfb = [
+            ['text' => self::DEFAULT_CORRECT_FEEDBACK, 'format' => FORMAT_HTML],
+        ];
+        $form->partpartiallycorrectfb = [
+            ['text' => self::DEFAULT_PARTIALLYCORRECT_FEEDBACK, 'format' => FORMAT_HTML],
+        ];
+        $form->partincorrectfb = [
+            ['text' => self::DEFAULT_INCORRECT_FEEDBACK, 'format' => FORMAT_HTML],
+        ];
+        $form->questiontext = ['text' => '<p>This question has a multichoice answer.</p>',
+                'format' => FORMAT_HTML];
+        $form->generalfeedback = ['text' => '', 'format' => FORMAT_HTML];
         $form->defaultmark = 2;
         $form->penalty = 0.3;
         $form->varsrandom = '';
@@ -1357,31 +1621,36 @@ public function get_formulas_question_form_data_testmc() {
         $form->answernumbering = '';
         $form->globalunitpenalty = 1;
         $form->globalruleid = 1;
-        $form->correctfeedback = array('text' => '', 'format' => FORMAT_HTML);
-        $form->partiallycorrectfeedback = array('text' => '', 'format' => FORMAT_HTML);
+        $form->correctfeedback = ['text' => 'Well done!', 'format' => FORMAT_HTML];
+        $form->partiallycorrectfeedback = [
+            'text' => 'Parts, but only parts, of your response are correct.',
+            'format' => FORMAT_HTML,
+        ];
         $form->shownumcorrect = '0';
-        $form->incorrectfeedback = array('text' => '', 'format' => FORMAT_HTML);
+        $form->incorrectfeedback = ['text' => 'That is not right at all.', 'format' => FORMAT_HTML];
         $form->numhints = 0;
         return $form;
     }
 
     /**
-     * @return qtype_formulas_question with a dropdown multichoice answer.
+     * Return Formulas question with one part, not randomized, drowdown multichoice answer.
+     *
+     * @return qtype_formulas_question
      */
-    public static function make_formulas_question_testmce() {
+    public static function make_formulas_question_testmce(): qtype_formulas_question {
         $q = self::make_a_formulas_question();
 
         $q->name = 'test-5';
         $q->questiontext = '<p>This question has a multichoice answer.</p>';
         $q->varsglobal = 'mychoices=["Dog","Cat","Bird","Fish"];';
         $q->penalty = 0.3; // Non-zero and not the default.
-        $q->textfragments = array(0 => '<p>This question has a multichoice answer.</p>',
-                                  1 => '');
+        $q->textfragments = [0 => '<p>This question has a multichoice answer.</p>',
+                                  1 => ''];
         $q->numpart = 1;
         $q->defaultmark = 2;
         $p = self::make_a_formulas_part();
         $p->id = 14;
-        $p->answermark = 1;
+        $p->answermark = 2;
         $p->answer = '1';
         $p->answernotunique = '1';
         $p->subqtext = '{_0:mychoices:MCE}';
@@ -1399,37 +1668,35 @@ public function get_formulas_question_form_data_testmce() {
 
         $form->name = 'test-5';
         $form->noanswers = 1;
-        $form->answer = array('1');
-        $form->answernotunique = array('1');
-        $form->answermark = array(1);
-        $form->answertype = array(0);
-        $form->correctness = array('_relerr < 0.01');
-        $form->numbox = array(1);
-        $form->placeholder = array('');
-        $form->vars1 = array('');
-        $form->vars2 = array('');
-        $form->ruleid = array(1);
-        $form->unitpenalty = array(1);
-        $form->postunit = array('');
-        $form->otherrule = array('');
-        $form->subqtext = array(
-            array('text' => '{_0:mychoices:MCE}', 'format' => FORMAT_HTML)
-        );
-        $form->feedback = array(
-            array('text' => '', 'format' => FORMAT_HTML)
-        );
-        $form->partcorrectfb = array(
-            array('text' => 'Your answer is correct.', 'format' => FORMAT_HTML)
-        );
-        $form->partpartiallycorrectfb = array(
-            array('text' => 'Your answer is partially correct.', 'format' => FORMAT_HTML)
-        );
-        $form->partincorrectfb = array(
-            array('text' => 'Your answer is incorrect.', 'format' => FORMAT_HTML)
-        );
-        $form->questiontext = array('text' => '<p>This question has a multichoice answer.</p>',
-                'format' => FORMAT_HTML);
-        $form->generalfeedback = array('text' => '', 'format' => FORMAT_HTML);
+        $form->answer = ['1'];
+        $form->answernotunique = ['1'];
+        $form->answermark = [2];
+        $form->answertype = ['0'];
+        $form->correctness = ['_relerr < 0.01'];
+        $form->numbox = [1];
+        $form->placeholder = [''];
+        $form->vars1 = [''];
+        $form->vars2 = [''];
+        $form->postunit = [''];
+        $form->otherrule = [''];
+        $form->subqtext = [
+            ['text' => '{_0:mychoices:MCE}', 'format' => FORMAT_HTML],
+        ];
+        $form->feedback = [
+            ['text' => '', 'format' => FORMAT_HTML],
+        ];
+        $form->partcorrectfb = [
+            ['text' => self::DEFAULT_CORRECT_FEEDBACK, 'format' => FORMAT_HTML],
+        ];
+        $form->partpartiallycorrectfb = [
+            ['text' => self::DEFAULT_PARTIALLYCORRECT_FEEDBACK, 'format' => FORMAT_HTML],
+        ];
+        $form->partincorrectfb = [
+            ['text' => self::DEFAULT_INCORRECT_FEEDBACK, 'format' => FORMAT_HTML],
+        ];
+        $form->questiontext = ['text' => '<p>This question has a multichoice answer.</p>',
+                'format' => FORMAT_HTML];
+        $form->generalfeedback = ['text' => '', 'format' => FORMAT_HTML];
         $form->defaultmark = 2;
         $form->penalty = 0.3;
         $form->varsrandom = '';
@@ -1437,18 +1704,23 @@ public function get_formulas_question_form_data_testmce() {
         $form->answernumbering = 'abc';
         $form->globalunitpenalty = 1;
         $form->globalruleid = 1;
-        $form->correctfeedback = array('text' => '', 'format' => FORMAT_HTML);
-        $form->partiallycorrectfeedback = array('text' => '', 'format' => FORMAT_HTML);
+        $form->correctfeedback = ['text' => 'Well done!', 'format' => FORMAT_HTML];
+        $form->partiallycorrectfeedback = [
+            'text' => 'Parts, but only parts, of your response are correct.',
+            'format' => FORMAT_HTML,
+        ];
         $form->shownumcorrect = '0';
-        $form->incorrectfeedback = array('text' => '', 'format' => FORMAT_HTML);
+        $form->incorrectfeedback = ['text' => 'That is not right at all.', 'format' => FORMAT_HTML];
         $form->numhints = 0;
         return $form;
     }
 
     /**
-     * @return qtype_formulas_question with two dropdown multichoice answers in separate parts.
+     * Return Formulas question with 2 parts, each with a drowdown multichoice answer.
+     *
+     * @return qtype_formulas_question
      */
-    public static function make_formulas_question_testmcetwoparts() {
+    public static function make_formulas_question_testmcetwoparts(): qtype_formulas_question {
         $q = self::make_a_formulas_question();
 
         $q->name = 'testmcetwoparts';
@@ -1456,10 +1728,10 @@ public static function make_formulas_question_testmcetwoparts() {
         $q->varsglobal = 'choices1=["Dog","Cat","Bird","Fish"];';
         $q->varsglobal .= 'choices2=["Red","Blue","Green","Yellow"];';
         $q->penalty = 0.3; // Non-zero and not the default.
-        $q->textfragments = array(0 => '<p>This question has two parts with a multichoice answer in each of them.</p>',
+        $q->textfragments = [0 => '<p>This question has two parts with a multichoice answer in each of them.</p>',
                                   1 => '{_0:choices1:MCE}',
-                                  2 => '{_0:choices2:MCE}'
-                            );
+                                  2 => '{_0:choices2:MCE}',
+                            ];
         $q->numpart = 1;
         $q->defaultmark = 2;
         $p1 = self::make_a_formulas_part();
@@ -1468,6 +1740,7 @@ public static function make_formulas_question_testmcetwoparts() {
         $p1->answer = '1';
         $p1->answernotunique = '1';
         $p1->subqtext = '{_0:choices1:MCE}';
+        $p1->partcorrectfb = 'Your first answer is correct.';
         $q->parts[0] = $p1;
         $p2 = self::make_a_formulas_part();
         $p2->id = 15;
@@ -1475,6 +1748,7 @@ public static function make_formulas_question_testmcetwoparts() {
         $p2->answer = '1';
         $p2->answernotunique = '1';
         $p2->subqtext = '{_0:choices2:MCE}';
+        $p2->partcorrectfb = 'Your second answer is correct.';
         $q->parts[1] = $p2;
 
         return $q;
@@ -1489,42 +1763,40 @@ public function get_formulas_question_form_data_testmcetwoparts() {
 
         $form->name = 'testmcetwoparts';
         $form->noanswers = 2;
-        $form->answer = array('1', '1');
-        $form->answernotunique = array('1', '1');
-        $form->answermark = array(1, 1);
-        $form->answertype = array(0, 0);
-        $form->correctness = array('_relerr < 0.01', '_relerr < 0.01');
-        $form->numbox = array(1, 1);
-        $form->placeholder = array('', '');
-        $form->vars1 = array('', '');
-        $form->vars2 = array('', '');
-        $form->ruleid = array(1, 1);
-        $form->unitpenalty = array(1, 1);
-        $form->postunit = array('', '');
-        $form->otherrule = array('', '');
-        $form->subqtext = array(
-            0 => array('text' => '{_0:choices1:MCE}', 'format' => FORMAT_HTML),
-            1 => array('text' => '{_0:choices2:MCE}', 'format' => FORMAT_HTML)
-        );
-        $form->feedback = array(
-            0 => array('text' => '', 'format' => FORMAT_HTML),
-            1 => array('text' => '', 'format' => FORMAT_HTML)
-        );
-        $form->partcorrectfb = array(
-            0 => array('text' => 'Your first answer is correct.', 'format' => FORMAT_HTML),
-            1 => array('text' => 'Your second answer is correct.', 'format' => FORMAT_HTML)
-        );
-        $form->partpartiallycorrectfb = array(
-            0 => array('text' => 'Your answer is partially correct.', 'format' => FORMAT_HTML),
-            1 => array('text' => 'Your answer is partially correct.', 'format' => FORMAT_HTML)
-        );
-        $form->partincorrectfb = array(
-            0 => array('text' => 'Your answer is incorrect.', 'format' => FORMAT_HTML),
-            1 => array('text' => 'Your answer is incorrect.', 'format' => FORMAT_HTML)
-        );
-        $form->questiontext = array('text' => '<p>This question has a multichoice answer.</p>',
-                'format' => FORMAT_HTML);
-        $form->generalfeedback = array('text' => '', 'format' => FORMAT_HTML);
+        $form->answer = ['1', '1'];
+        $form->answernotunique = ['1', '1'];
+        $form->answermark = [1, 1];
+        $form->answertype = ['0', '0'];
+        $form->correctness = ['_relerr < 0.01', '_relerr < 0.01'];
+        $form->numbox = [1, 1];
+        $form->placeholder = ['', ''];
+        $form->vars1 = ['', ''];
+        $form->vars2 = ['', ''];
+        $form->postunit = ['', ''];
+        $form->otherrule = ['', ''];
+        $form->subqtext = [
+            0 => ['text' => '{_0:choices1:MCE}', 'format' => FORMAT_HTML],
+            1 => ['text' => '{_0:choices2:MCE}', 'format' => FORMAT_HTML],
+        ];
+        $form->feedback = [
+            0 => ['text' => '', 'format' => FORMAT_HTML],
+            1 => ['text' => '', 'format' => FORMAT_HTML],
+        ];
+        $form->partcorrectfb = [
+            0 => ['text' => 'Your first answer is correct.', 'format' => FORMAT_HTML],
+            1 => ['text' => 'Your second answer is correct.', 'format' => FORMAT_HTML],
+        ];
+        $form->partpartiallycorrectfb = [
+            0 => ['text' => self::DEFAULT_PARTIALLYCORRECT_FEEDBACK, 'format' => FORMAT_HTML],
+            1 => ['text' => self::DEFAULT_PARTIALLYCORRECT_FEEDBACK, 'format' => FORMAT_HTML],
+        ];
+        $form->partincorrectfb = [
+            0 => ['text' => self::DEFAULT_INCORRECT_FEEDBACK, 'format' => FORMAT_HTML],
+            1 => ['text' => self::DEFAULT_INCORRECT_FEEDBACK, 'format' => FORMAT_HTML],
+        ];
+        $form->questiontext = ['text' => '<p>This question has two parts with a multichoice answer in each of them.</p>',
+                'format' => FORMAT_HTML];
+        $form->generalfeedback = ['text' => '', 'format' => FORMAT_HTML];
         $form->defaultmark = 2;
         $form->penalty = 0.3;
         $form->varsrandom = '';
@@ -1533,18 +1805,23 @@ public function get_formulas_question_form_data_testmcetwoparts() {
         $form->answernumbering = '';
         $form->globalunitpenalty = 1;
         $form->globalruleid = 1;
-        $form->correctfeedback = array('text' => '', 'format' => FORMAT_HTML);
-        $form->partiallycorrectfeedback = array('text' => '', 'format' => FORMAT_HTML);
+        $form->correctfeedback = ['text' => 'Well done!', 'format' => FORMAT_HTML];
+        $form->partiallycorrectfeedback = [
+            'text' => 'Parts, but only parts, of your response are correct.',
+            'format' => FORMAT_HTML,
+        ];
         $form->shownumcorrect = '0';
-        $form->incorrectfeedback = array('text' => '', 'format' => FORMAT_HTML);
+        $form->incorrectfeedback = ['text' => 'That is not right at all.', 'format' => FORMAT_HTML];
         $form->numhints = 0;
         return $form;
     }
 
     /**
-     * @return qtype_formulas_question with two radio button multichoice answers in separate parts.
+     * Formulas question with 2 parts, each with a radio button multichoice answer.
+     *
+     * @return qtype_formulas_question
      */
-    public static function make_formulas_question_testmctwoparts() {
+    public static function make_formulas_question_testmctwoparts(): qtype_formulas_question {
         $q = self::make_a_formulas_question();
 
         $q->name = 'testmcetwoparts';
@@ -1552,10 +1829,10 @@ public static function make_formulas_question_testmctwoparts() {
         $q->varsglobal = 'choices1=["Dog","Cat","Bird","Fish"];';
         $q->varsglobal .= 'choices2=["Red","Blue","Green","Yellow"];';
         $q->penalty = 0.3; // Non-zero and not the default.
-        $q->textfragments = array(0 => '<p>This question has two parts with a multichoice answer in each of them.</p>',
-                                  1 => 'Part 1 -- {_0:choices1:MC}',
-                                  2 => 'Part 2 -- {_0:choices2:MC}'
-                            );
+        $q->textfragments = [0 => '<p>This question has two parts with a multichoice answer in each of them.</p>',
+                                  1 => 'Part 1 -- {_0:choices1}',
+                                  2 => 'Part 2 -- {_0:choices2}',
+                            ];
         $q->numpart = 1;
         $q->defaultmark = 2;
         $p1 = self::make_a_formulas_part();
@@ -1563,14 +1840,16 @@ public static function make_formulas_question_testmctwoparts() {
         $p1->answermark = 1;
         $p1->answer = '1';
         $p1->answernotunique = '1';
-        $p1->subqtext = 'Part 1 -- {_0:choices1:MCE}';
+        $p1->subqtext = 'Part 1 -- {_0:choices1}';
+        $p1->partcorrectfb = 'Your first answer is correct.';
         $q->parts[0] = $p1;
         $p2 = self::make_a_formulas_part();
         $p2->id = 15;
         $p2->answermark = 1;
         $p2->answer = '1';
         $p2->answernotunique = '1';
-        $p2->subqtext = 'Part 2 -- {_0:choices2:MCE}';
+        $p2->subqtext = 'Part 2 -- {_0:choices2}';
+        $p2->partcorrectfb = 'Your second answer is correct.';
         $q->parts[1] = $p2;
 
         return $q;
@@ -1585,42 +1864,40 @@ public function get_formulas_question_form_data_testmctwoparts() {
 
         $form->name = 'testmcetwoparts';
         $form->noanswers = 2;
-        $form->answer = array('1', '1');
-        $form->answernotunique = array('1', '1');
-        $form->answermark = array(1, 1);
-        $form->answertype = array(0, 0);
-        $form->correctness = array('_relerr < 0.01', '_relerr < 0.01');
-        $form->numbox = array(1, 1);
-        $form->placeholder = array('', '');
-        $form->vars1 = array('', '');
-        $form->vars2 = array('', '');
-        $form->ruleid = array(1, 1);
-        $form->unitpenalty = array(1, 1);
-        $form->postunit = array('', '');
-        $form->otherrule = array('', '');
-        $form->subqtext = array(
-            0 => array('text' => 'Part 1 -- {_0:choices1:MC}', 'format' => FORMAT_HTML),
-            1 => array('text' => 'Part 2 -- {_0:choices2:MC}', 'format' => FORMAT_HTML)
-        );
-        $form->feedback = array(
-            0 => array('text' => '', 'format' => FORMAT_HTML),
-            1 => array('text' => '', 'format' => FORMAT_HTML)
-        );
-        $form->partcorrectfb = array(
-            0 => array('text' => 'Your first answer is correct.', 'format' => FORMAT_HTML),
-            1 => array('text' => 'Your second answer is correct.', 'format' => FORMAT_HTML)
-        );
-        $form->partpartiallycorrectfb = array(
-            0 => array('text' => 'Your answer is partially correct.', 'format' => FORMAT_HTML),
-            1 => array('text' => 'Your answer is partially correct.', 'format' => FORMAT_HTML)
-        );
-        $form->partincorrectfb = array(
-            0 => array('text' => 'Your answer is incorrect.', 'format' => FORMAT_HTML),
-            1 => array('text' => 'Your answer is incorrect.', 'format' => FORMAT_HTML)
-        );
-        $form->questiontext = array('text' => '<p>This question has two parts with a multichoice answer in each of them.</p>',
-                'format' => FORMAT_HTML);
-        $form->generalfeedback = array('text' => '', 'format' => FORMAT_HTML);
+        $form->answer = ['1', '1'];
+        $form->answernotunique = ['1', '1'];
+        $form->answermark = [1, 1];
+        $form->answertype = ['0', '0'];
+        $form->correctness = ['_relerr < 0.01', '_relerr < 0.01'];
+        $form->numbox = [1, 1];
+        $form->placeholder = ['', ''];
+        $form->vars1 = ['', ''];
+        $form->vars2 = ['', ''];
+        $form->postunit = ['', ''];
+        $form->otherrule = ['', ''];
+        $form->subqtext = [
+            0 => ['text' => 'Part 1 -- {_0:choices1}', 'format' => FORMAT_HTML],
+            1 => ['text' => 'Part 2 -- {_0:choices2}', 'format' => FORMAT_HTML],
+        ];
+        $form->feedback = [
+            0 => ['text' => '', 'format' => FORMAT_HTML],
+            1 => ['text' => '', 'format' => FORMAT_HTML],
+        ];
+        $form->partcorrectfb = [
+            0 => ['text' => 'Your first answer is correct.', 'format' => FORMAT_HTML],
+            1 => ['text' => 'Your second answer is correct.', 'format' => FORMAT_HTML],
+        ];
+        $form->partpartiallycorrectfb = [
+            0 => ['text' => self::DEFAULT_PARTIALLYCORRECT_FEEDBACK, 'format' => FORMAT_HTML],
+            1 => ['text' => self::DEFAULT_PARTIALLYCORRECT_FEEDBACK, 'format' => FORMAT_HTML],
+        ];
+        $form->partincorrectfb = [
+            0 => ['text' => self::DEFAULT_INCORRECT_FEEDBACK, 'format' => FORMAT_HTML],
+            1 => ['text' => self::DEFAULT_INCORRECT_FEEDBACK, 'format' => FORMAT_HTML],
+        ];
+        $form->questiontext = ['text' => '<p>This question has two parts with a multichoice answer in each of them.</p>',
+                'format' => FORMAT_HTML];
+        $form->generalfeedback = ['text' => '', 'format' => FORMAT_HTML];
         $form->defaultmark = 2;
         $form->penalty = 0.3;
         $form->varsrandom = '';
@@ -1629,43 +1906,57 @@ public function get_formulas_question_form_data_testmctwoparts() {
         $form->answernumbering = '';
         $form->globalunitpenalty = 1;
         $form->globalruleid = 1;
-        $form->correctfeedback = array('text' => '', 'format' => FORMAT_HTML);
-        $form->partiallycorrectfeedback = array('text' => '', 'format' => FORMAT_HTML);
+        $form->correctfeedback = ['text' => 'Well done!', 'format' => FORMAT_HTML];
+        $form->partiallycorrectfeedback = [
+            'text' => 'Parts, but only parts, of your response are correct.',
+            'format' => FORMAT_HTML,
+        ];
         $form->shownumcorrect = '0';
-        $form->incorrectfeedback = array('text' => '', 'format' => FORMAT_HTML);
+        $form->incorrectfeedback = ['text' => 'That is not right at all.', 'format' => FORMAT_HTML];
         $form->numhints = 0;
         return $form;
     }
 
     /**
-     * @return qtype_formulas_question with two parts and two numbers in each of them.
+     * Return Formulas question with 2 parts, each one with 2 numbers.
+     *
+     * @return qtype_formulas_question
      */
-    public static function make_formulas_question_testtwoandtwo() {
+    public static function make_formulas_question_testtwoandtwo(): qtype_formulas_question {
         $q = self::make_a_formulas_question();
 
         $q->name = 'testtwoandtwo';
         $q->questiontext = '<p>This question has two parts with two numbers in each of them.</p>';
-        $q->varsglobal = '';
         $q->penalty = 0.3; // Non-zero and not the default.
-        $q->textfragments = array(0 => '<p>This question has two parts with two numbers in each of them.</p>',
-                                  1 => 'Part 1 -- {_0} -- {_1}',
-                                  2 => 'Part 2 -- {_0} -- {_1}'
-                            );
-        $q->numpart = 1;
+        $q->textfragments = [
+            0 => '<p>This question has two parts with two numbers in each of them.</p>',
+            1 => '',
+            2 => '',
+        ];
+        $q->numpart = 2;
         $q->defaultmark = 2;
+
         $p1 = self::make_a_formulas_part();
         $p1->id = 14;
+        $p1->questionid = $q->id;
         $p1->answermark = 1;
-        $p1->answer = ['1', '2'];
+        $p1->answer = '[1, 2]';
+        $p1->numbox = 2;
         $p1->answernotunique = '1';
         $p1->subqtext = 'Part 1 -- {_0} -- {_1}';
+        $p1->partcorrectfb = 'Your answers in part 1 are correct.';
         $q->parts[0] = $p1;
+
         $p2 = self::make_a_formulas_part();
         $p2->id = 15;
+        $p2->partindex = 1;
+        $p2->questionid = $q->id;
         $p2->answermark = 1;
-        $p2->answer = ['3', '4'];
+        $p2->answer = '[3, 4]';
+        $p2->numbox = 2;
         $p2->answernotunique = '1';
         $p2->subqtext = 'Part 2 -- {_0} -- {_1}';
+        $p2->partcorrectfb = 'Your answers in part 2 are correct.';
         $q->parts[1] = $p2;
 
         return $q;
@@ -1679,55 +1970,160 @@ public function get_formulas_question_form_data_testtwoandtwo() {
         $form = new stdClass();
 
         $form->name = 'testtwoandtwo';
-        $form->noanswers = 4;
-        $form->answer = array(0 => '[1, 2]', 1 => '[3, 4]');
-        $form->answernotunique = array('1', '1');
-        $form->answermark = array(0 => 1, 1 => 1);
-        $form->answertype = array(0, 0);
-        $form->correctness = array('_relerr < 0.01', '_relerr < 0.01');
-        $form->numbox = array(1, 1);
-        $form->placeholder = array('', '');
-        $form->vars1 = array('', '');
-        $form->vars2 = array('', '');
-        $form->ruleid = array(1, 1);
-        $form->unitpenalty = array(1, 1);
-        $form->postunit = array('', '');
-        $form->otherrule = array('', '');
-        $form->subqtext = array(
-            0 => array('text' => 'Part 1 -- {_0} -- {_1}', 'format' => FORMAT_HTML),
-            1 => array('text' => 'Part 2 -- {_0} -- {_1}', 'format' => FORMAT_HTML)
-        );
-        $form->feedback = array(
-            0 => array('text' => '', 'format' => FORMAT_HTML),
-            1 => array('text' => '', 'format' => FORMAT_HTML)
-        );
-        $form->partcorrectfb = array(
-            0 => array('text' => 'Your answers in part 1 are correct.', 'format' => FORMAT_HTML),
-            1 => array('text' => 'Your answers in part 2 are correct.', 'format' => FORMAT_HTML)
-        );
-        $form->partpartiallycorrectfb = array(
-            0 => array('text' => 'Your answer is partially correct.', 'format' => FORMAT_HTML),
-            1 => array('text' => 'Your answer is partially correct.', 'format' => FORMAT_HTML)
-        );
-        $form->partincorrectfb = array(
-            0 => array('text' => 'Your answer is incorrect.', 'format' => FORMAT_HTML),
-            1 => array('text' => 'Your answer is incorrect.', 'format' => FORMAT_HTML)
-        );
-        $form->questiontext = array('text' => '<p>This question has two parts with two numbers in each of them.</p>',
-                'format' => FORMAT_HTML);
-        $form->generalfeedback = array('text' => '', 'format' => FORMAT_HTML);
+        $form->noanswers = 2;
+        $form->answer = [0 => '[1, 2]', 1 => '[3, 4]'];
+        $form->answernotunique = ['1', '1'];
+        $form->answermark = [0 => 1, 1 => 1];
+        $form->answertype = ['0', '0'];
+        $form->correctness = ['_relerr < 0.01', '_relerr < 0.01'];
+        $form->numbox = [2, 2];
+        $form->placeholder = ['', ''];
+        $form->vars1 = ['', ''];
+        $form->vars2 = ['', ''];
+        $form->postunit = ['', ''];
+        $form->otherrule = ['', ''];
+        $form->subqtext = [
+            0 => ['text' => 'Part 1 -- {_0} -- {_1}', 'format' => FORMAT_HTML],
+            1 => ['text' => 'Part 2 -- {_0} -- {_1}', 'format' => FORMAT_HTML],
+        ];
+        $form->feedback = [
+            0 => ['text' => '', 'format' => FORMAT_HTML],
+            1 => ['text' => '', 'format' => FORMAT_HTML],
+        ];
+        $form->partcorrectfb = [
+            0 => ['text' => 'Your answers in part 1 are correct.', 'format' => FORMAT_HTML],
+            1 => ['text' => 'Your answers in part 2 are correct.', 'format' => FORMAT_HTML],
+        ];
+        $form->partpartiallycorrectfb = [
+            0 => ['text' => self::DEFAULT_PARTIALLYCORRECT_FEEDBACK, 'format' => FORMAT_HTML],
+            1 => ['text' => self::DEFAULT_PARTIALLYCORRECT_FEEDBACK, 'format' => FORMAT_HTML],
+        ];
+        $form->partincorrectfb = [
+            0 => ['text' => self::DEFAULT_INCORRECT_FEEDBACK, 'format' => FORMAT_HTML],
+            1 => ['text' => self::DEFAULT_INCORRECT_FEEDBACK, 'format' => FORMAT_HTML],
+        ];
+        $form->questiontext = [
+            'text' => '<p>This question has two parts with two numbers in each of them.</p>',
+            'format' => FORMAT_HTML,
+        ];
+        $form->generalfeedback = ['text' => '', 'format' => FORMAT_HTML];
         $form->defaultmark = 2;
         $form->penalty = 0.3;
         $form->varsrandom = '';
         $form->varsglobal = '';
-        $form->answernumbering = '';
+        $form->answernumbering = 'abc';
         $form->globalunitpenalty = 1;
         $form->globalruleid = 1;
-        $form->correctfeedback = array('text' => '', 'format' => FORMAT_HTML);
-        $form->partiallycorrectfeedback = array('text' => '', 'format' => FORMAT_HTML);
-        $form->shownumcorrect = '0';
-        $form->incorrectfeedback = array('text' => '', 'format' => FORMAT_HTML);
-        $form->numhints = 0;
+        $form->correctfeedback = [
+            'text' => test_question_maker::STANDARD_OVERALL_CORRECT_FEEDBACK,
+            'format' => FORMAT_HTML,
+        ];
+        $form->partiallycorrectfeedback = [
+            'text' => test_question_maker::STANDARD_OVERALL_PARTIALLYCORRECT_FEEDBACK,
+            'format' => FORMAT_HTML,
+        ];
+        $form->incorrectfeedback = [
+            'text' => test_question_maker::STANDARD_OVERALL_INCORRECT_FEEDBACK,
+            'format' => FORMAT_HTML,
+        ];
+        $form->shownumcorrect = 1;
+
         return $form;
     }
-}
+
+    /**
+     * Return question data for the testtwoandtwo Formulas question.
+     *
+     * @return stdClass
+     */
+    public static function get_formulas_question_data_testtwoandtwo(): stdClass {
+        $qdata = new stdClass();
+        test_question_maker::initialise_question_data($qdata);
+
+        $qdata->qtype = 'formulas';
+        $qdata->name = 'testtwoandtwo';
+        $qdata->questiontext = '<p>This question has two parts with two numbers in each of them.</p>';
+        $qdata->generalfeedback = '';
+        $qdata->defaultmark = 2;
+        $qdata->penalty = 0.3;
+
+        $qdata->options = new stdClass();
+        $qdata->contextid = context_system::instance()->id;
+        $qdata->options->varsrandom = '';
+        $qdata->options->varsglobal = '';
+        $qdata->options->answernumbering = 'abc';
+        $qdata->options->shownumcorrect = 1;
+        $qdata->options->correctfeedback =
+                test_question_maker::STANDARD_OVERALL_CORRECT_FEEDBACK;
+        $qdata->options->correctfeedbackformat = FORMAT_HTML;
+        $qdata->options->partiallycorrectfeedback =
+                test_question_maker::STANDARD_OVERALL_PARTIALLYCORRECT_FEEDBACK;
+        $qdata->options->partiallycorrectfeedbackformat = FORMAT_HTML;
+        $qdata->options->incorrectfeedback =
+                test_question_maker::STANDARD_OVERALL_INCORRECT_FEEDBACK;
+        $qdata->options->incorrectfeedbackformat = FORMAT_HTML;
+
+        $qdata->options->answers = [
+            14 => (object)[
+                'id' => 14,
+                'questionid' => $qdata->id,
+                'placeholder' => '',
+                'answermark' => 1,
+                'answertype' => '0',
+                'numbox' => 2,
+                'vars1' => '',
+                'vars2' => '',
+                'answer' => '[1, 2]',
+                'answernotunique' => '1',
+                'correctness' => '_relerr < 0.01',
+                'unitpenalty' => 1,
+                'postunit' => '',
+                'ruleid' => 1,
+                'otherrule' => '',
+                'subqtext' => 'Part 1 -- {_0} -- {_1}',
+                'subqtextformat' => FORMAT_HTML,
+                'feedback' => '',
+                'feedbackformat' => FORMAT_HTML,
+                'partcorrectfb' => 'Your answers in part 1 are correct.',
+                'partcorrectfbformat' => FORMAT_HTML,
+                'partpartiallycorrectfb' => self::DEFAULT_PARTIALLYCORRECT_FEEDBACK,
+                'partpartiallycorrectfbformat' => FORMAT_HTML,
+                'partincorrectfb' => self::DEFAULT_INCORRECT_FEEDBACK,
+                'partincorrectfbformat' => FORMAT_HTML,
+                'partindex' => 0,
+            ],
+            15 => (object)[
+                'id' => 15,
+                'questionid' => $qdata->id,
+                'placeholder' => '',
+                'answermark' => 1,
+                'answertype' => '0',
+                'numbox' => 2,
+                'vars1' => '',
+                'vars2' => '',
+                'answer' => '[3, 4]',
+                'answernotunique' => '1',
+                'correctness' => '_relerr < 0.01',
+                'unitpenalty' => 1,
+                'postunit' => '',
+                'ruleid' => 1,
+                'otherrule' => '',
+                'subqtext' => 'Part 2 -- {_0} -- {_1}',
+                'subqtextformat' => FORMAT_HTML,
+                'feedback' => '',
+                'feedbackformat' => FORMAT_HTML,
+                'partcorrectfb' => 'Your answers in part 2 are correct.',
+                'partcorrectfbformat' => FORMAT_HTML,
+                'partpartiallycorrectfb' => self::DEFAULT_PARTIALLYCORRECT_FEEDBACK,
+                'partpartiallycorrectfbformat' => FORMAT_HTML,
+                'partincorrectfb' => self::DEFAULT_INCORRECT_FEEDBACK,
+                'partincorrectfbformat' => FORMAT_HTML,
+                'partindex' => 1,
+            ],
+        ];
+
+        $qdata->options->numpart = 2;
+
+        return $qdata;
+    }
+}
\ No newline at end of file

From a53ca06140da13670c1f40d87c5387a82f612ee1 Mon Sep 17 00:00:00 2001
From: Philipp Imhof <52650214+PhilippImhof@users.noreply.github.com>
Date: Sun, 16 Mar 2025 11:43:13 +0100
Subject: [PATCH 3/5] fix failing tests

---
 tests/behat/quiz.feature | 10 +++++-----
 tests/helper.php         |  1 +
 2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/tests/behat/quiz.feature b/tests/behat/quiz.feature
index 1caf70e8..f5240b55 100644
--- a/tests/behat/quiz.feature
+++ b/tests/behat/quiz.feature
@@ -37,7 +37,7 @@ Feature: Usage in quiz
       | quiz     | Quiz 7  | C1     | quiz7    |
       | quiz     | Quiz 8  | C1     | quiz8    |
       | quiz     | Quiz 9  | C1     | quiz9    |
-      | quiz     | Quiz 10 | C1     | quiz9    |
+      | quiz     | Quiz 10 | C1     | quiz10   |
     And quiz "Quiz 1" contains the following questions:
       | question  | page |
       | singlenum | 1    |
@@ -80,7 +80,7 @@ Feature: Usage in quiz
     # And I click on "Submit all and finish" "button" in the "Confirmation" "dialogue"
     # And I click on "Submit all and finish" "button" in the "Submit all your answers and finish?" "dialogue"
     # And I confirm the quiz submission in the modal dialog
-    Then I should see "Your answer is correct."
+    Then I should see "Correct answer, well done."
 
   Scenario: Try to answer a question with one part and two answer fields
     When I follow "Quiz 2"
@@ -109,7 +109,7 @@ Feature: Usage in quiz
     And I press "Finish attempt"
     And I press "Submit all and finish"
     # And I confirm the quiz submission in the modal dialog
-    Then I should see "Your answer is correct."
+    Then I should see "Correct answer, well done."
 
   Scenario: Try to answer a question with three parts and one answer field each
     When I follow "Quiz 5"
@@ -134,7 +134,7 @@ Feature: Usage in quiz
     And I press "Finish attempt"
     And I press "Submit all and finish"
     And I confirm the quiz submission in the modal dialog for the formulas plugin
-    Then I should see "Your answer is correct."
+    Then I should see "Correct answer, well done."
 
   Scenario: Try to answer a drowdown multiple choice formula question
     When I follow "Quiz 7"
@@ -143,7 +143,7 @@ Feature: Usage in quiz
     And I press "Finish attempt"
     And I press "Submit all and finish"
     # And I confirm the quiz submission in the modal dialog
-    Then I should see "Your answer is correct."
+    Then I should see "Correct answer, well done."
 
   Scenario: Try to answer a question with two parts, one drowdown multiple choice in each of them
     When I follow "Quiz 8"
diff --git a/tests/helper.php b/tests/helper.php
index 88a80f42..17c0f850 100644
--- a/tests/helper.php
+++ b/tests/helper.php
@@ -84,6 +84,7 @@ protected static function make_a_formulas_question() {
         $q->varsrandom = '';
         $q->varsglobal = '';
         $q->answernumbering = 'abc';
+        $q->qv = new qtype_formulas\variables();
         $q->penalty = 0.2;
         $q->generalfeedback = '';
         test_question_maker::set_standard_combined_feedback_fields($q);

From 2689dd31ca13145b8110849b9b4a6f54e14e20c1 Mon Sep 17 00:00:00 2001
From: Philipp Imhof <52650214+PhilippImhof@users.noreply.github.com>
Date: Sun, 16 Mar 2025 13:27:32 +0100
Subject: [PATCH 4/5] add workaround for Moodle < 4.0

---
 tests/backup_restore_test.php                 | 11 ++++++--
 tests/behat/mobile.feature                    | 10 +++----
 .../dummy_quiz_question_helper_test_trait.php | 28 +++++++++++++++++++
 3 files changed, 42 insertions(+), 7 deletions(-)
 create mode 100644 tests/dummy_quiz_question_helper_test_trait.php

diff --git a/tests/backup_restore_test.php b/tests/backup_restore_test.php
index 646efd39..aa47cd4c 100644
--- a/tests/backup_restore_test.php
+++ b/tests/backup_restore_test.php
@@ -39,11 +39,18 @@
 require_once($CFG->dirroot . '/backup/util/includes/backup_includes.php');
 require_once($CFG->dirroot . '/backup/util/includes/restore_includes.php');
 require_once($CFG->dirroot . '/mod/quiz/locallib.php');
-require_once($CFG->dirroot . '/mod/quiz/tests/quiz_question_helper_test_trait.php');
 require_once($CFG->dirroot . '/question/engine/tests/helpers.php');
 require_once($CFG->dirroot . '/question/type/formulas/questiontype.php');
 require_once($CFG->dirroot . '/question/type/formulas/tests/helper.php');
 
+if (file_exists($CFG->dirroot . '/mod/quiz/tests/quiz_question_helper_test_trait.php')) {
+    require_once($CFG->dirroot . '/mod/quiz/tests/quiz_question_helper_test_trait.php');
+    class_alias('\quiz_question_helper_test_trait', '\trait_class_alias');
+} else {
+    require_once($CFG->dirroot . '/question/type/formulas/tests/dummy_quiz_question_helper_test_trait.php');
+    class_alias('\qtype_formulas\dummy_quiz_question_helper_test_trait', '\trait_class_alias');
+}
+
 /**
  * Unit tests for backup and restore.
  *
@@ -57,7 +64,7 @@
  * @covers     \qtype_formulas_part
  */
 final class backup_restore_test extends \advanced_testcase {
-    use \quiz_question_helper_test_trait;
+    use \trait_class_alias;
 
     /**
      * Create a question object of a certain type, as defined in the helper.php file.
diff --git a/tests/behat/mobile.feature b/tests/behat/mobile.feature
index 67abcb6d..9ce2111d 100644
--- a/tests/behat/mobile.feature
+++ b/tests/behat/mobile.feature
@@ -37,7 +37,7 @@ Feature: Mobile compatibility
       | quiz     | Quiz 7  | C1     | quiz7    |
       | quiz     | Quiz 8  | C1     | quiz8    |
       | quiz     | Quiz 9  | C1     | quiz9    |
-      | quiz     | Quiz 10 | C1     | quiz9    |
+      | quiz     | Quiz 10 | C1     | quiz10   |
     And quiz "Quiz 1" contains the following questions:
       | question  | page |
       | singlenum | 1    |
@@ -79,7 +79,7 @@ Feature: Mobile compatibility
     And I press "Submit" in the app
     And I press "Submit all and finish" in the app
     And I press "Submit" near "Once you submit" in the app
-    Then I should find "Your answer is correct." in the app
+    Then I should find "Correct answer, well done." in the app
 
   Scenario: Try to answer a question with one part and two answer fields
     When I press "Quiz 2" in the app
@@ -108,7 +108,7 @@ Feature: Mobile compatibility
     And I press "Submit" in the app
     And I press "Submit all and finish" in the app
     And I press "Submit" near "Once you submit" in the app
-    Then I should find "Your answer is correct." in the app
+    Then I should find "Correct answer, well done." in the app
 
   Scenario: Try to answer a question with three parts and one answer field each
     When I press "Quiz 5" in the app
@@ -130,7 +130,7 @@ Feature: Mobile compatibility
     And I press "Submit" in the app
     And I press "Submit all and finish" in the app
     And I press "Submit" near "Once you submit" in the app
-    Then I should find "Your answer is correct." in the app
+    Then I should find "Correct answer, well done." in the app
 
   Scenario: Try to answer a drowdown multiple choice formula question
     When I press "Quiz 7" in the app
@@ -140,7 +140,7 @@ Feature: Mobile compatibility
     And I press "Submit" in the app
     And I press "Submit all and finish" in the app
     And I press "Submit" near "Once you submit" in the app
-    Then I should find "Your answer is correct." in the app
+    Then I should find "Correct answer, well done." in the app
 
   Scenario: Try to answer a question with two parts, one drowdown multiple choice in each of them
     When I press "Quiz 8" in the app
diff --git a/tests/dummy_quiz_question_helper_test_trait.php b/tests/dummy_quiz_question_helper_test_trait.php
new file mode 100644
index 00000000..c677810f
--- /dev/null
+++ b/tests/dummy_quiz_question_helper_test_trait.php
@@ -0,0 +1,28 @@
+<?php
+// This file is part of Moodle - https://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <https://www.gnu.org/licenses/>.
+
+namespace qtype_formulas;
+
+/**
+ * Empty dummy trait for Moodle < 4.0 where the real quiz_question_helper_test_trait is not available.
+ *
+ * @package    qtype_formulas
+ * @category   test
+ * @copyright  2025 Philipp Imhof
+ * @license    https://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+trait dummy_quiz_question_helper_test_trait {
+}

From 5c2b3d891ea158d89df79e93cf795b426f330fdb Mon Sep 17 00:00:00 2001
From: Philipp Imhof <52650214+PhilippImhof@users.noreply.github.com>
Date: Sun, 16 Mar 2025 13:48:13 +0100
Subject: [PATCH 5/5] cleanup, skip test for Moodle < 4.0

---
 tests/backup_restore_test.php | 15 +++++----------
 1 file changed, 5 insertions(+), 10 deletions(-)

diff --git a/tests/backup_restore_test.php b/tests/backup_restore_test.php
index aa47cd4c..729fc2c6 100644
--- a/tests/backup_restore_test.php
+++ b/tests/backup_restore_test.php
@@ -66,15 +66,6 @@ class_alias('\qtype_formulas\dummy_quiz_question_helper_test_trait', '\trait_cla
 final class backup_restore_test extends \advanced_testcase {
     use \trait_class_alias;
 
-    /**
-     * Create a question object of a certain type, as defined in the helper.php file.
-     *
-     * @return qtype_formulas_question
-     */
-    protected function get_test_formulas_question($which = null) {
-        return test_question_maker::make_question('formulas', $which);
-    }
-
     /**
      * Data provider.
      *
@@ -100,7 +91,11 @@ public static function provide_question_names(): array {
      * @dataProvider provide_question_names
      */
     public function test_backup_and_restore(string $questionname): void {
-        global $USER, $DB;
+        global $CFG, $USER, $DB;
+
+        if ($CFG->branch < 400) {
+            $this->markTestSkipped('Not testing backup and restore in Moodle < 4.0');
+        }
 
         // Login as admin user.
         $this->resetAfterTest(true);