diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index de284d8..c5c3909 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -90,7 +90,7 @@ jobs:
 
       - name: Moodle Code Checker
         if: ${{ always() }}
-        run: moodle-plugin-ci phpcs --max-warnings 0
+        run: moodle-plugin-ci phpcs # --max-warnings 0 # Add back once #[\Override] works.
 
       - name: Moodle PHPDoc Checker
         continue-on-error: true # This step will show errors but will not fail.
diff --git a/backup/moodle2/backup_qtype_oumatrix_plugin.class.php b/backup/moodle2/backup_qtype_oumatrix_plugin.class.php
index 4e778e5..5fdff32 100644
--- a/backup/moodle2/backup_qtype_oumatrix_plugin.class.php
+++ b/backup/moodle2/backup_qtype_oumatrix_plugin.class.php
@@ -66,6 +66,7 @@ protected function define_question_plugin_structure(): backup_plugin_element {
         return $plugin;
     }
 
+    #[\Override]
     public static function get_qtype_fileareas() {
         return [
             'feedback' => 'qtype_oumatrix_rows',
diff --git a/edit_oumatrix_form.php b/edit_oumatrix_form.php
index 891dbb2..db6ad55 100644
--- a/edit_oumatrix_form.php
+++ b/edit_oumatrix_form.php
@@ -27,22 +27,22 @@
 class qtype_oumatrix_edit_form extends question_edit_form {
 
     /** The default starting number of columns (answers). */
-    private const COL_NUM_START = 3;
+    protected const COL_NUM_START = 3;
 
     /** The number of columns (answers) that get added at a time. */
-    private const COL_NUM_ADD = 2;
+    protected const COL_NUM_ADD = 2;
 
     /** The default starting number of rows (question row). */
-    private const ROW_NUM_START = 4;
+    protected const ROW_NUM_START = 4;
 
     /** The number of rows (question row) that get added at a time.*/
-    private const ROW_NUM_ADD = 2;
+    protected const ROW_NUM_ADD = 2;
 
     /** @var int Number of columns. */
-    private $numcolumns;
+    protected int $numcolumns;
 
     /** @var string inputtype of rows. */
-    private $inputtype;
+    protected string $inputtype;
 
     /** @var array of HTML tags allowed in column and row names. */
     protected $allowedhtmltags = [
@@ -54,10 +54,10 @@ class qtype_oumatrix_edit_form extends question_edit_form {
     ];
 
     /** @var string regex to match HTML open tags. */
-    private $htmltstarttagsandattributes = '~<\s*\w+\b[^>]*>~';
+    protected string $htmltstarttagsandattributes = '~<\s*\w+\b[^>]*>~';
 
     /** @var string regex to match HTML close tags or br. */
-    private $htmltclosetags = '~<\s*/\s*\w+\b[^>]*>~';
+    protected string $htmltclosetags = '~<\s*/\s*\w+\b[^>]*>~';
 
     /**
      * Set the inputtype and number of rows and columns method.
@@ -81,6 +81,7 @@ protected function set_current_settings(): void {
         $this->numcolumns = $columns ? count($columns) : $this->numcolumns;
     }
 
+    #[\Override]
     protected function definition_inner($mform) {
 
         // Set the number of columns and rows.
@@ -210,6 +211,7 @@ protected function get_per_row_fields(MoodleQuickForm $mform, string $label, arr
         return $repeated;
     }
 
+    #[\Override]
     public function data_preprocessing($question) {
         $question = parent::data_preprocessing($question);
         $question = $this->data_preprocessing_options($question);
@@ -310,6 +312,7 @@ private function data_preprocessing_rows(stdClass $question): object {
         return $question;
     }
 
+    #[\Override]
     public function validation($data, $files) {
         $errors = parent::validation($data, $files);
 
@@ -448,8 +451,8 @@ public function validation($data, $files) {
     }
 
     /**
-     * Vaidate some input to make sure it does not contain any tags other than
-     * $this->allowedhtmltags.
+     * Validate some input to make sure it does not contain any tags other than $this->allowedhtmltags.
+     *
      * @param string $text the input to validate.
      * @return string any validation errors.
      */
@@ -506,12 +509,7 @@ private function get_list_of_printable_allowed_tags(array $allowedhtmltags): str
         return implode(', ', $allowedtaglist);
     }
 
-
-    /**
-     * Returns the question type name.
-     *
-     * @return string The question type name.
-     */
+    #[\Override]
     public function qtype(): string {
         return 'oumatrix';
     }
diff --git a/question.php b/question.php
index b666500..b13589b 100644
--- a/question.php
+++ b/question.php
@@ -34,26 +34,38 @@
  * @license     https://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  */
 abstract class qtype_oumatrix_base extends question_graded_automatically {
-    public $shuffleanswers;
+    /** @var bool whether the rows should be shuffled. */
+    public bool $shuffleanswers;
 
     /** @var string 'All or none' or 'partial' grading method for multiple response. */
-    public $grademethod;
+    public string $grademethod;
 
-    public $correctfeedback;
-    public $correctfeedbackformat;
-    public $partiallycorrectfeedback;
-    public $partiallycorrectfeedbackformat;
-    public $incorrectfeedback;
-    public $incorrectfeedbackformat;
+    /** @var string feedback for any correct response. */
+    public string $correctfeedback;
+
+    /** @var int format of $correctfeedback. */
+    public int $correctfeedbackformat;
+
+    /** @var string feedback for any partially correct response. */
+    public string $partiallycorrectfeedback;
+
+    /** @var int format of $partiallycorrectfeedback. */
+    public int $partiallycorrectfeedbackformat;
+
+    /** @var string feedback for any incorrect response. */
+    public string $incorrectfeedback;
+
+    /** @var int format of $incorrectfeedback. */
+    public int $incorrectfeedbackformat;
 
     /** @var column[] The columns (answers) object, indexed by number. */
-    public $columns;
+    public array $columns;
 
     /** @var row[] The rows (subquestions) object, indexed by number. */
-    public $rows;
+    public array $rows;
 
     /** @var array The order of the rows, key => row number. */
-    protected $roworder = null;
+    protected ?array $roworder = null;
 
     /**
      * Returns true if the response has been selected for that row and column.
@@ -65,10 +77,13 @@ abstract class qtype_oumatrix_base extends question_graded_automatically {
      */
     abstract public function is_choice_selected(array $response, int $rowkey, int $colnumber): bool;
 
+    #[\Override]
     abstract public function is_same_response(array $prevresponse, array $newresponse);
 
+    #[\Override]
     abstract public function grade_response(array $response);
 
+    #[\Override]
     public function start_attempt(question_attempt_step $step, $variant) {
         $this->roworder = array_keys($this->rows);
         if ($this->shuffleanswers) {
@@ -77,6 +92,7 @@ public function start_attempt(question_attempt_step $step, $variant) {
         $step->set_qt_var('_roworder', implode(',', $this->roworder));
     }
 
+    #[\Override]
     public function apply_attempt_state(question_attempt_step $step) {
         $this->roworder = explode(',', $step->get_qt_var('_roworder'));
     }
@@ -103,10 +119,12 @@ protected function init_roworder(question_attempt $qa) {
         }
     }
 
+    #[\Override]
     public function is_gradable_response(array $response) {
         return $this->is_complete_response($response);
     }
 
+    #[\Override]
     public function check_file_access($qa, $options, $component, $filearea, $args, $forcedownload) {
         if ($component == 'question' && in_array($filearea,
                         ['correctfeedback', 'partiallycorrectfeedback', 'incorrectfeedback'])) {
@@ -124,6 +142,7 @@ public function check_file_access($qa, $options, $component, $filearea, $args, $
         }
     }
 
+    #[\Override]
     public function get_validation_error(array $response): string {
         if ($this->is_complete_response($response)) {
             return '';
@@ -131,6 +150,7 @@ public function get_validation_error(array $response): string {
         return get_string('pleaseananswerallparts', 'qtype_oumatrix');
     }
 
+    #[\Override]
     public function validate_can_regrade_with_other_version(question_definition $otherversion): ?string {
         $basemessage = parent::validate_can_regrade_with_other_version($otherversion);
         if ($basemessage) {
@@ -168,10 +188,12 @@ public function has_specific_feedback(): bool {
  */
 class qtype_oumatrix_single extends qtype_oumatrix_base {
 
+    #[\Override]
     public function get_renderer(moodle_page $page) {
         return $page->get_renderer('qtype_oumatrix', 'single');
     }
 
+    #[\Override]
     public function get_expected_data(): array {
         $expected = [];
         foreach ($this->rows as $row) {
@@ -180,6 +202,7 @@ public function get_expected_data(): array {
         return $expected;
     }
 
+    #[\Override]
     public function is_choice_selected(array $response, int $rowkey, int $colnumber): bool {
         $responsekey = $this->field($rowkey);
         if (array_key_exists($responsekey, $response)) {
@@ -188,6 +211,7 @@ public function is_choice_selected(array $response, int $rowkey, int $colnumber)
         return false;
     }
 
+    #[\Override]
     public function is_same_response(array $prevresponse, array $newresponse): bool {
         foreach ($this->roworder as $key => $notused) {
             $fieldname = $this->field($key);
@@ -208,6 +232,7 @@ protected function field(int $rowkey): string {
         return 'rowanswers' . $rowkey;
     }
 
+    #[\Override]
     public function get_correct_response(): array {
         $response = [];
         foreach ($this->roworder as $key => $rownumber) {
@@ -220,6 +245,7 @@ public function get_correct_response(): array {
         return $response;
     }
 
+    #[\Override]
     public function summarise_response(array $response): ?string {
         $responsewords = [];
         foreach ($this->roworder as $key => $rownumber) {
@@ -238,6 +264,7 @@ public function summarise_response(array $response): ?string {
         return implode('; ', $responsewords);
     }
 
+    #[\Override]
     public function is_complete_response(array $response): bool {
         foreach ($this->roworder as $key => $rownumber) {
             $fieldname = $this->field($key);
@@ -248,6 +275,7 @@ public function is_complete_response(array $response): bool {
         return true;
     }
 
+    #[\Override]
     public function classify_response(array $response): array {
         $classifiedresponse = [];
         foreach ($this->roworder as $key => $rownumber) {
@@ -269,6 +297,7 @@ public function classify_response(array $response): array {
         return $classifiedresponse;
     }
 
+    #[\Override]
     public function prepare_simulated_post_data($simulatedresponse): array {
         // Expected structure of $simulatedresponse is Row field name => Col name.
         // Each row must be present, in order.
@@ -293,6 +322,7 @@ public function prepare_simulated_post_data($simulatedresponse): array {
         return $postdata;
     }
 
+    #[\Override]
     public function grade_response(array $response): array {
         // Retrieve the number of right responses and the total number of responses.
         [$numrightparts, $total] = $this->get_num_parts_right($response);
@@ -300,6 +330,7 @@ public function grade_response(array $response): array {
         return [$fraction, question_state::graded_state_for_fraction($fraction)];
     }
 
+    #[\Override]
     public function get_num_parts_right(array $response): array {
         $numright = 0;
         foreach ($this->roworder as $key => $rownumber) {
@@ -318,10 +349,12 @@ public function get_num_parts_right(array $response): array {
      */
 class qtype_oumatrix_multiple extends qtype_oumatrix_base {
 
+    #[\Override]
     public function get_renderer(moodle_page $page) {
         return $page->get_renderer('qtype_oumatrix', 'multiple');
     }
 
+    #[\Override]
     public function get_expected_data(): array {
         $expected = [];
         foreach ($this->rows as $row) {
@@ -332,6 +365,7 @@ public function get_expected_data(): array {
         return $expected;
     }
 
+    #[\Override]
     public function is_choice_selected(array $response, int $rowkey, int $colnumber): bool {
         $responsekey = $this->field($rowkey, $colnumber);
         if (array_key_exists($responsekey, $response)) {
@@ -351,6 +385,7 @@ protected function field(int $rowkey, int $columnnumber): string {
         return 'rowanswers' . $rowkey . '_' . $columnnumber;
     }
 
+    #[\Override]
     public function is_same_response(array $prevresponse, array $newresponse): bool {
         foreach ($this->roworder as $key => $notused) {
             foreach ($this->columns as $column) {
@@ -363,6 +398,7 @@ public function is_same_response(array $prevresponse, array $newresponse): bool
         return true;
     }
 
+    #[\Override]
     public function get_correct_response(): ?array {
         $response = [];
         foreach ($this->roworder as $key => $rownumber) {
@@ -375,6 +411,7 @@ public function get_correct_response(): ?array {
         return $response;
     }
 
+    #[\Override]
     public function summarise_response(array $response): ?string {
         $responsewords = [];
         foreach ($this->roworder as $key => $rownumber) {
@@ -396,6 +433,7 @@ public function summarise_response(array $response): ?string {
         return implode('; ', $responsewords);
     }
 
+    #[\Override]
     public function is_complete_response(array $response): bool {
         foreach ($this->roworder as $key => $rownumber) {
             $inputresponse = false;
@@ -412,6 +450,7 @@ public function is_complete_response(array $response): bool {
         return true;
     }
 
+    #[\Override]
     public function classify_response(array $response) {
         $classifiedresponse = [];
         foreach ($this->roworder as $rowkey => $rownumber) {
@@ -433,6 +472,7 @@ public function classify_response(array $response) {
         return $classifiedresponse;
     }
 
+    #[\Override]
     public function prepare_simulated_post_data($simulatedresponse): array {
         $postdata = [];
         $subquestions = array_keys($simulatedresponse);
@@ -457,6 +497,7 @@ public function prepare_simulated_post_data($simulatedresponse): array {
         return $postdata;
     }
 
+    #[\Override]
     public function grade_response(array $response): array {
         // Retrieve the number of right responses and the total number of responses.
         if ($this->grademethod == 'allnone') {
@@ -527,6 +568,8 @@ public function get_num_parts_grade_partial(array $response): array {
     }
 
     /**
+     * Get the number of selected choices in a response.
+     *
      * @param array $response responses, as returned by
      *      {@link question_attempt_step::get_qt_data()}.
      * @return int the number of choices that were selected in this response.
diff --git a/questiontype.php b/questiontype.php
index 4fc4064..3094bc5 100644
--- a/questiontype.php
+++ b/questiontype.php
@@ -34,6 +34,8 @@
  * @license   https://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  */
 class qtype_oumatrix extends question_type {
+
+    #[\Override]
     public function get_question_options($question) {
         global $DB, $OUTPUT;
         parent::get_question_options($question);
@@ -52,6 +54,7 @@ public function get_question_options($question) {
         return true;
     }
 
+    #[\Override]
     public function save_defaults_for_new_questions(stdClass $fromform): void {
         parent::save_defaults_for_new_questions($fromform);
         $this->set_default_value('inputtype', $fromform->inputtype);
@@ -60,6 +63,7 @@ public function save_defaults_for_new_questions(stdClass $fromform): void {
         $this->set_default_value('shownumcorrect', $fromform->shownumcorrect);
     }
 
+    #[\Override]
     public function save_question_options($question) {
         global $DB;
         $context = $question->context;
@@ -168,6 +172,7 @@ public function save_rows(stdClass $question, array $columnslist) {
         }
     }
 
+    #[\Override]
     protected function make_question_instance($questiondata) {
         question_bank::load_question_definition_classes($this->name());
         if ($questiondata->options->inputtype === 'single') {
@@ -178,6 +183,7 @@ protected function make_question_instance($questiondata) {
         return new $class();
     }
 
+    #[\Override]
     protected function initialise_question_instance(question_definition $question, $questiondata) {
         parent::initialise_question_instance($question, $questiondata);
         $question->grademethod = $questiondata->options->grademethod;
@@ -245,10 +251,12 @@ public function make_row(stdClass $rowdata): row {
                 explode(',', $rowdata->correctanswers), $rowdata->feedback, $rowdata->feedbackformat);
     }
 
+    #[\Override]
     protected function make_hint($hint) {
         return question_hint_with_parts::load_from_record($hint);
     }
 
+    #[\Override]
     public function delete_question($questionid, $contextid) {
         global $DB;
         $DB->delete_records('qtype_oumatrix_options', ['questionid' => $questionid]);
@@ -257,6 +265,7 @@ public function delete_question($questionid, $contextid) {
         parent::delete_question($questionid, $contextid);
     }
 
+    #[\Override]
     public function get_random_guess_score($questiondata) {
         // We compute the random guess score here on the assumption we are using
         // the deferred feedback behaviour, and the question text tells the
@@ -288,10 +297,11 @@ public function get_random_guess_score($questiondata) {
 
     /**
      * Return total number if choices for both (single, multiple) matrix choices.
+     *
      * @param stdClass $questiondata
      * @return int|null
      */
-    public function get_total_number_of_choices(object $questiondata): ?int {
+    public function get_total_number_of_choices(stdClass $questiondata): ?int {
         // If rows or columns are not set return null.
         if (count($questiondata->columns) === 0 || count($questiondata->rows) === 0) {
             return null;
@@ -304,7 +314,7 @@ public function get_total_number_of_choices(object $questiondata): ?int {
     /**
      * Returns the count of correct answers for the question.
      *
-     * @param stdClass The question data
+     * @param stdClass $questiondata The question data
      * @return int the number of choices that are correct.
      */
     public function get_num_correct_choices(stdClass $questiondata): int {
@@ -315,6 +325,7 @@ public function get_num_correct_choices(stdClass $questiondata): int {
         return $numright;
     }
 
+    #[\Override]
     public function get_possible_responses($questiondata) {
         if ($questiondata->options->inputtype == 'single') {
             return $this->get_possible_responses_single($questiondata);
@@ -368,6 +379,7 @@ protected function get_possible_responses_multiple(stdClass $questiondata): arra
         return $parts;
     }
 
+    #[\Override]
     public function import_from_xml($data, $question, qformat_xml $format, $extra = null) {
         if (!isset($data['@']['type']) || $data['@']['type'] != 'oumatrix') {
             return false;
@@ -465,6 +477,7 @@ public function import_rows(qformat_xml $format, stdClass $question, array $rows
         }
     }
 
+    #[\Override]
     public function export_to_xml($question, qformat_xml $format, $extra = null) {
         $output = '';
 
@@ -514,6 +527,7 @@ public function export_to_xml($question, qformat_xml $format, $extra = null) {
         return $output;
     }
 
+    #[\Override]
     public function move_files($questionid, $oldcontextid, $newcontextid) {
         $fs = get_file_storage();
 
@@ -530,8 +544,7 @@ public function move_files($questionid, $oldcontextid, $newcontextid) {
     }
 
     /**
-     * Move all the feedback files belonging to each sub-question
-     * when the question is moved from one context to another.
+     * Move the feedback files related to the row feedback.
      *
      * @param int $questionid the question being moved.
      * @param int $oldcontextid the context it is moving from.
@@ -549,6 +562,7 @@ protected function move_files_in_row_feedback(int $questionid, int $oldcontextid
         }
     }
 
+    #[\Override]
     protected function delete_files($questionid, $contextid) {
         $fs = get_file_storage();
 
diff --git a/renderer.php b/renderer.php
index abdeb42..99c1c33 100644
--- a/renderer.php
+++ b/renderer.php
@@ -36,6 +36,7 @@ abstract class qtype_oumatrix_renderer_base extends qtype_with_combined_feedback
 
     /**
      * Returns the value as radio/checkbox based on the single choice or multiple response question.
+     *
      * @return string
      */
     abstract protected function get_input_type(): string;
@@ -86,10 +87,12 @@ protected function is_right(question_definition $question, int $rowkey, int $col
         return 0;
     }
 
+    #[\Override]
     protected function feedback_class($fraction) {
         return question_state::graded_state_for_fraction($fraction)->get_feedback_class();
     }
 
+    #[\Override]
     protected function feedback_image($fraction, $selected = true) {
         $feedbackclass = question_state::graded_state_for_fraction($fraction)->get_feedback_class();
 
@@ -99,6 +102,7 @@ protected function feedback_image($fraction, $selected = true) {
             ['class' => 'position-absolute ml-1 mt-1']);
     }
 
+    #[\Override]
     public function formulation_and_controls(question_attempt $qa,
             question_display_options $options) {
         $question = $qa->get_question();
@@ -224,12 +228,14 @@ public function matrix_table(question_attempt $qa, question_display_options $opt
         return $table;
     }
 
+    #[\Override]
     public function specific_feedback(question_attempt $qa) {
         return $this->combined_feedback($qa);
     }
 
     /**
      * Function returns string based on number of correct answers
+     *
      * @param array $right An Array of correct responses to the current question
      * @return string based on number of correct responses
      */
@@ -253,22 +259,28 @@ protected function correct_choices(array $right): string {
  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  */
 class qtype_oumatrix_single_renderer extends qtype_oumatrix_renderer_base {
+
+    #[\Override]
     protected function get_input_type(): string {
         return 'radio';
     }
 
+    #[\Override]
     protected function get_input_name(question_attempt $qa, int $rowkey, int $columnnumber): string {
         return $qa->get_qt_field_name('rowanswers' . $rowkey);
     }
 
+    #[\Override]
     protected function get_input_value(int $value): string {
         return $value;
     }
 
+    #[\Override]
     protected function get_input_id(question_attempt $qa, int $rowkey, int $columnnumber): string {
         return $qa->get_qt_field_name('rowanswers' . $rowkey . '_' . $columnnumber);
     }
 
+    #[\Override]
     public function correct_response(question_attempt $qa) {
         $question = $qa->get_question();
         $right = [];
@@ -278,6 +290,7 @@ public function correct_response(question_attempt $qa) {
         return $this->correct_choices($right);
     }
 
+    #[\Override]
     protected function num_parts_correct(question_attempt $qa): string {
         $a = new stdClass();
         list($a->num, $a->outof) = $qa->get_question()->get_num_parts_right(
@@ -301,22 +314,28 @@ protected function num_parts_correct(question_attempt $qa): string {
  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  */
 class qtype_oumatrix_multiple_renderer extends qtype_oumatrix_renderer_base {
+
+    #[\Override]
     protected function get_input_type(): string {
         return 'checkbox';
     }
 
+    #[\Override]
     protected function get_input_name(question_attempt $qa, int $rowkey, int $columnnumber): string {
         return $qa->get_qt_field_name('rowanswers' . $rowkey . '_' . $columnnumber);
     }
 
+    #[\Override]
     protected function get_input_value(int $value): string {
         return "1";
     }
 
+    #[\Override]
     protected function get_input_id(question_attempt $qa, int $rowkey, int $columnnumber): string {
         return $this->get_input_name($qa, $rowkey, $columnnumber);
     }
 
+    #[\Override]
     public function correct_response(question_attempt $qa) {
         $question = $qa->get_question();
         foreach ($question->rows as $row) {
@@ -334,6 +353,7 @@ public function correct_response(question_attempt $qa) {
         return $this->correct_choices($rightanswers);
     }
 
+    #[\Override]
     protected function num_parts_correct(question_attempt $qa): string {
         if ($qa->get_question()->get_num_selected_choices($qa->get_last_qt_data()) >
                 $qa->get_question()->get_num_correct_choices()) {
diff --git a/tests/edit_oumatrix_form_test.php b/tests/edit_oumatrix_form_test.php
index 5f68e42..d415e30 100644
--- a/tests/edit_oumatrix_form_test.php
+++ b/tests/edit_oumatrix_form_test.php
@@ -84,8 +84,7 @@ protected function get_form(string $classname): array {
      */
     public function test_validation_cols_rows_minimum(): void {
         [$form, $category] = $this->get_form('qtype_oumatrix_edit_form');
-        $helper = new qtype_oumatrix_test_helper();
-        $formdata = $helper->get_test_question_form_data('animals_single');
+        $formdata = \test_question_maker::get_question_form_data('oumatrix', 'animals_single');
         $formdata['category'] = $category->id;
 
         // Minumum number of columns.
@@ -116,8 +115,7 @@ public function test_validation_cols_rows_minimum(): void {
      */
     public function test_validation_cols_rows_duplicates(): void {
         [$form, $category] = $this->get_form('qtype_oumatrix_edit_form');
-        $helper = new qtype_oumatrix_test_helper();
-        $formdata = $helper->get_test_question_form_data('animals_single');
+        $formdata = \test_question_maker::get_question_form_data('oumatrix', 'animals_single');
         $formdata['category'] = $category->id;
 
         // Duplicate a column name.
@@ -144,8 +142,7 @@ public function test_validation_cols_rows_duplicates(): void {
      */
     public function test_validation_column_names_empty(): void {
         [$form, $category] = $this->get_form('qtype_oumatrix_edit_form');
-        $helper = new qtype_oumatrix_test_helper();
-        $formdata = $helper->get_test_question_form_data('animals_single');
+        $formdata = \test_question_maker::get_question_form_data('oumatrix', 'animals_single');
         $formdata['category'] = $category->id;
 
         // Empty columns names (second and third columns are empty).
@@ -168,8 +165,7 @@ public function test_validation_column_names_empty(): void {
      */
     public function test_validation_rowanswers(): void {
         [$form, $category] = $this->get_form('qtype_oumatrix_edit_form');
-        $helper = new qtype_oumatrix_test_helper();
-        $formdata = $helper->get_test_question_form_data('animals_single');
+        $formdata = \test_question_maker::get_question_form_data('oumatrix', 'animals_single');
         $formdata['category'] = $category->id;
 
         // Rows without chosen answer(s) are not valid.
@@ -188,10 +184,9 @@ public function test_validation_rowanswers(): void {
      */
     public function test_validation_rowanswers_on_empty_columns(): void {
         [$form, $category] = $this->get_form('qtype_oumatrix_edit_form');
-        $helper = new qtype_oumatrix_test_helper();
 
         // Single choice test.
-        $formdata = $helper->get_test_question_form_data('animals_single');
+        $formdata = \test_question_maker::get_question_form_data('oumatrix', 'animals_single');
         $formdata['category'] = $category->id;
 
         // Rows with chosen answer on empty columns are not valid(single choice).
@@ -207,7 +202,7 @@ public function test_validation_rowanswers_on_empty_columns(): void {
         $this->assertEquals($expectedanswer, $errors['rowoptions[1]']);
 
         // Multiple response test.
-        $formdata = $helper->get_test_question_form_data('food_multiple');
+        $formdata = \test_question_maker::get_question_form_data('oumatrix', 'food_multiple');
         $formdata['category'] = $category->id;
 
         // Rows with chosen answers on empty columns are not valid(multi response).
@@ -225,10 +220,9 @@ public function test_validation_rowanswers_on_empty_columns(): void {
      */
     public function test_get_illegal_tag_error(): void {
         [$form, $category] = $this->get_form('qtype_oumatrix_edit_form');
-        $helper = new qtype_oumatrix_test_helper();
 
         // Single choice test.
-        $formdata = $helper->get_test_question_form_data('animals_single');
+        $formdata = \test_question_maker::get_question_form_data('oumatrix', 'animals_single');
         $formdata['category'] = $category->id;
         $testdata = $formdata;
 
diff --git a/tests/helper.php b/tests/helper.php
index 084d849..18d87d0 100644
--- a/tests/helper.php
+++ b/tests/helper.php
@@ -27,6 +27,7 @@
  */
 class qtype_oumatrix_test_helper extends question_test_helper {
 
+    #[\Override]
     public function get_test_questions(): array {
         return [
                 'animals_single',
@@ -441,14 +442,6 @@ public static function get_oumatrix_question_form_data_food_multiple(): stdClass
         return $qfdata;
     }
 
-    public function get_test_question_data(string $which) {
-        return \test_question_maker::get_question_data('oumatrix', $which);
-    }
-
-    public function get_test_question_form_data(string $which) {
-        return (array)\test_question_maker::get_question_form_data('oumatrix', $which);
-    }
-
     /**
      * Returns a qtype_oumatrix_single question.
      *
diff --git a/tests/questiontype_test.php b/tests/questiontype_test.php
index 42896fc..07aebdd 100644
--- a/tests/questiontype_test.php
+++ b/tests/questiontype_test.php
@@ -39,13 +39,16 @@
  * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  * @covers    \qtype_oumatrix
  */
-class questiontype_test extends \advanced_testcase {
-    protected $qtype;
+final class questiontype_test extends \advanced_testcase {
+    /** @var qtype_oumatrix|null instance of the question type to use in tests. */
+    protected ?qtype_oumatrix $qtype;
 
+    #[\Override]
     protected function setUp(): void {
         $this->qtype = new qtype_oumatrix();
     }
 
+    #[\Override]
     protected function tearDown(): void {
         $this->qtype = null;
     }
@@ -54,20 +57,17 @@ public function test_name(): void {
         $this->assertEquals($this->qtype->name(), 'oumatrix');
     }
 
-
     public function test_get_random_guess_score(): void {
-        $helper = new qtype_oumatrix_test_helper();
 
-        $qdata = $helper->get_test_question_data('animals_single');
+        $qdata = \test_question_maker::get_question_data('oumatrix', 'animals_single');
         $this->assertEquals(0.25, $this->qtype->get_random_guess_score($qdata));
 
-        $qdata = $helper->get_test_question_data('food_multiple');
+        $qdata = \test_question_maker::get_question_data('oumatrix', 'food_multiple');
         $this->assertEquals(null, $this->qtype->get_random_guess_score($qdata));
     }
 
     public function test_get_random_guess_score_broken_question(): void {
-        $helper = new qtype_oumatrix_test_helper();
-        $q = $helper->get_test_question_data('animals_single');
+        $q = \test_question_maker::get_question_data('oumatrix', 'animals_single');
         $q->columns = [];
         $this->assertNull($this->qtype->get_random_guess_score($q));
     }
@@ -147,10 +147,6 @@ public function test_get_possible_responses_multiple(): void {
         $this->assertEquals($expected, $this->qtype->get_possible_responses($q));
     }
 
-    public function get_save_question_which() {
-        return [['animals_single'], ['oumatrix_multiple']];
-    }
-
     public function test_load_question(): void {
         $this->resetAfterTest();