Merge branch 'MDL-77378_402_v3' of https://github.com/TomoTsuyuki/moodle

 into MOODLE_402_STABLE

question/type/multianswer/question.php

@@ -147,6 +147,9 @@ public function get_min_fraction() {
             $fractionmax += $subq->defaultmark;
             $fractionsum += $subq->defaultmark * $subq->get_min_fraction();
         }
+        if (empty($fractionsum)) {
+            return 0;
+        }
         return $fractionsum / (!empty($this->subquestions) ? $fractionmax : 1);
     }
 
@@ -157,6 +160,9 @@ public function get_max_fraction() {
             $fractionmax += $subq->defaultmark;
             $fractionsum += $subq->defaultmark * $subq->get_max_fraction();
         }
+        if (empty($fractionsum)) {
+            return 1;
+        }
         return $fractionsum / (!empty($this->subquestions) ? $fractionmax : 1);
     }
 
@@ -299,6 +305,9 @@ public function grade_response(array $response) {
                 $overallstate = $this->combine_states($overallstate, $newstate);
             }
         }
+        if (empty($fractionmax)) {
+            return array(null, $overallstate ?? question_state::$finished);
+        }
         return array($fractionsum / $fractionmax, $overallstate);
     }
 

question/type/multianswer/tests/helper.php

@@ -37,7 +37,7 @@
  */
 class qtype_multianswer_test_helper extends question_test_helper {
     public function get_test_questions() {
-        return array('twosubq', 'fourmc', 'numericalzero', 'dollarsigns', 'multiple');
+        return array('twosubq', 'fourmc', 'numericalzero', 'dollarsigns', 'multiple', 'zeroweight');
     }
 
     /**
@@ -484,4 +484,48 @@ public function make_multianswer_question_multiple() {
         return $q;
     }
 
+    /**
+     * Makes a multianswer question with zero weight.
+     * This is used for testing the MDL-77378 bug.
+     * @return qtype_multianswer_question
+     */
+    public function make_multianswer_question_zeroweight() {
+        question_bank::load_question_definition_classes('multianswer');
+        $q = new qtype_multianswer_question();
+        test_question_maker::initialise_a_question($q);
+        $q->name = 'Zero weight';
+        $q->questiontext =
+            'Optional question: {#1}.';
+        $q->generalfeedback = '';
+        $q->qtype = question_bank::get_qtype('multianswer');
+        $q->textfragments = array(
+            'Optional question: ',
+            '.',
+        );
+        $q->places = array('1' => '1');
+
+        // Shortanswer subquestion.
+        question_bank::load_question_definition_classes('shortanswer');
+        $sa = new qtype_shortanswer_question();
+        test_question_maker::initialise_a_question($sa);
+        $sa->name = 'Zero weight';
+        $sa->questiontext = '{0:SHORTANSWER:~%0%Input box~%100%*}';
+        $sa->questiontextformat = FORMAT_HTML;
+        $sa->generalfeedback = '';
+        $sa->generalfeedbackformat = FORMAT_HTML;
+        $sa->usecase = true;
+        $sa->answers = array(
+            13 => new question_answer(13, 'Input box', 0.0, '', FORMAT_HTML),
+            14 => new question_answer(14, '*', 1.0, '', FORMAT_HTML),
+        );
+        $sa->qtype = question_bank::get_qtype('shortanswer');
+        $sa->defaultmark = 0;
+
+        $q->subquestions = array(
+            1 => $sa,
+        );
+
+        return $q;
+    }
+
 }

question/type/multianswer/tests/question_test.php

@@ -350,4 +350,23 @@ public function test_update_attempt_state_date_from_old_version_ok() {
                 $newquestion->update_attempt_state_data_for_new_version($oldstep, $question));
     }
 
+    /**
+     * Test functions work with zero weight.
+     * This is used for testing the MDL-77378 bug.
+     */
+    public function test_zeroweight() {
+        $this->resetAfterTest();
+        /** @var \qtype_multianswer_question $question */
+        $question = \test_question_maker::make_question('multianswer', 'zeroweight');
+        $question->start_attempt(new question_attempt_step(), 1);
+
+        $this->assertEquals([null, question_state::$gradedright], $question->grade_response(
+            ['sub1_answer' => 'Something']));
+        $this->assertEquals([null, question_state::$gradedwrong], $question->grade_response(
+            ['sub1_answer' => 'Input box']));
+
+        $this->assertEquals(1, $question->get_max_fraction());
+        $this->assertEquals(0, $question->get_min_fraction());
+    }
+
 }