feedback, correct answer, update behat

Author: PhilippImhof

classes/local/answer_parser.php

@@ -85,9 +85,18 @@ public function __construct($tokenlist, array $knownvariables = [], bool $caretm
     public function is_acceptable_for_answertype(int $type, bool $acceptempty = false): bool {
         // An empty answer is never acceptable regardless of the answer type, unless empty fields
         // are explicitly allowed for a question's part.
+        // FIXME: this can be removed later
         if (empty($this->tokenlist)) {
             return $acceptempty;
         }
+        $firsttoken = reset($this->tokenlist);
+        if (count($this->tokenlist) === 1 && $firsttoken->type === token::EMPTY) {
+            return $acceptempty;
+        }
+        if (empty($this->tokenlist)) {
+            return $acceptempty;
+        }
+
         if ($type === qtype_formulas::ANSWER_TYPE_NUMBER) {
             return $this->is_acceptable_number();
         }

lang/en/qtype_formulas.php

@@ -103,6 +103,7 @@
 $string['defaultwidthunit_desc'] = 'Unit of length used for the default width settings below. The units "em" or "rem" correspond approximately to the width of one digit.';
 $string['emptyallowed'] = 'Students may leave one or more fields empty.';
 $string['emptyallowed_help'] = 'Check this option for parts where not all fields have to be filled, e. g. when you have two fields for an equation that could have just one solution, and you do not want to give away the number of solutions.';
+$string['emptyanswer'] = '[empty]';
 $string['error_algebraic_relerr'] = 'Relative error (_relerr) cannot be used with answer type algebraic formula.';
 $string['error_algvar_numbers'] = 'Algebraic variables can only be initialized with a list of numbers.';
 $string['error_answer_missing'] = 'No answer has been defined.';

question.php

@@ -460,6 +460,9 @@ public function check_file_access($qa, $options, $component, $filearea, $args, $
      * @return bool whether this response can be graded
      */
     public function is_gradable_response(array $response): bool {
+        if (array_key_exists('_seed', $response)) {
+            return false;
+        }
         // Iterate over all parts. If at least one part is gradable, we can leave early.
         foreach ($this->parts as $part) {
             if ($part->is_gradable_response($response)) {
@@ -523,7 +526,7 @@ public function summarise_response(array $response) {
         foreach ($this->parts as $part) {
             $summary[] = $part->summarise_response($response);
         }
-        return implode(', ', $summary);
+        return implode('; ', $summary);
     }
 
     /**
@@ -1266,6 +1269,9 @@ public function is_complete_response(array $response): bool {
      * @return bool
      */
     public function is_unanswered(array $response): bool {
+        if (array_key_exists('_seed', $response)) {
+            return true;
+        }
         if (!array_key_exists('normalized', $response)) {
             $response = $this->normalize_response($response);
         }
@@ -1646,8 +1652,12 @@ public function get_correct_response(bool $forfeedback = false): array {
         $answers = $this->get_evaluated_answers();
 
         // Numeric answers should be localized, if that functionality is enabled.
+        // Empty answers should be just the empty string; a more user-friendly
+        // output will be created in the renderer.
         foreach ($answers as &$answer) {
-            if (is_numeric($answer)) {
+            if ($answer === '$EMPTY') {
+                $answer = '';
+            } else if (is_numeric($answer)) {
                 $answer = qtype_formulas::format_float($answer);
             }
         }

renderer.php

@@ -749,6 +749,11 @@ public function correct_response(question_attempt $qa) {
      */
     public function part_correct_response($part) {
         $answers = $part->get_correct_response(true);
+        foreach ($answers as &$answer) {
+            if ($answer === '') {
+                $answer = get_string('emptyanswer', 'qtype_formulas');
+            }
+        }
         $answertext = implode('; ', $answers);
 
         $string = ($part->answernotunique ? 'correctansweris' : 'uniquecorrectansweris');

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 "6250" and "6500" bytes
+    Then following "click here" should download between "6400" and "6600" 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