MDL-29427 quiz nav: information items should should have a state tooltip

mod/quiz/attemptlib.php

@@ -1236,7 +1236,7 @@ public function get_question_buttons() {
             if (!$showcorrectness && $button->stateclass == 'notanswered') {
                 $button->stateclass = 'complete';
             }
-            $button->statestring = $qa->get_state_string($showcorrectness);
+            $button->statestring = $this->get_state_string($qa, $showcorrectness);
             $button->currentpage = $qa->get_question()->_page == $this->page;
             $button->flagged     = $qa->is_flagged();
             $button->url         = $this->get_question_url($slot);
@@ -1246,6 +1246,19 @@ public function get_question_buttons() {
         return $buttons;
     }
 
+    protected function get_state_string(question_attempt $qa, $showcorrectness) {
+        if ($qa->get_question()->length > 0)  {
+            return $qa->get_state_string($showcorrectness);
+        }
+
+        // Special case handling for 'information' items.
+        if ($qa->get_state() == question_state::$todo) {
+            return get_string('notyetviewed', 'quiz');
+        } else {
+            return get_string('viewed', 'quiz');
+        }
+    }
+
     public function render_before_button_bits(mod_quiz_renderer $output) {
         return '';
     }

mod/quiz/lang/en/quiz.php

@@ -453,6 +453,7 @@
 $string['notenoughsubquestions'] = 'Not enough sub-questions have been defined!<br />Do you want to go back and fix this question?';
 $string['notimedependentitems'] = 'Time dependent items are not currently supported by the quiz module. As a work around, set a time limit for the whole quiz. Do you wish to choose a different item (or use the current item regardless)?';
 $string['notyetgraded'] = 'Not yet graded';
+$string['notyetviewed'] = 'Not yet viewed';
 $string['notyourattempt'] = 'This is not your attempt!';
 $string['noview'] = 'Logged-in user is not allowed to view this quiz';
 $string['numattempts'] = '{$a->studentnum} {$a->studentstring} have made {$a->attemptnum} attempts';
@@ -775,6 +776,7 @@
 $string['validate'] = 'Validate';
 $string['viewallanswers'] = 'View {$a} quiz attempts';
 $string['viewallreports'] = 'View reports for {$a} attempts';
+$string['viewed'] = 'Viewed';
 $string['warningmissingtype'] = '<b>This question is of a type that has not been installed on your Moodle yet.<br />Please alert your Moodle administrator.</b>';
 $string['wheregrade'] = 'Where\'s my grade?';
 $string['wildcard'] = 'Wild card';