Preview window add "Close preview" button fix studentquiz#469.

preview.php

@@ -158,6 +158,12 @@
 
  echo $quba->render_question($slot, $options, 'i');
 
+ $returnurl = new moodle_url('/mod/studentquiz/view.php', ['id' => $cmid]);
+ echo html_writer::start_div('controls input-group', ['id' => 'previewcontrols']);
+ echo html_writer::link($returnurl, get_string('closepreview', 'question'),
+ ['class' => 'btn btn-secondary mr-1 mb-1', 'role' => 'button']);
+ echo html_writer::end_div();
+
  $PAGE->requires->js_module('core_question_engine');
  $PAGE->requires->strings_for_js(array(
  'closepreview',

tests/behat/preview_question.feature

@@ -113,3 +113,22 @@ Feature: Preview a question as a student
  And I should see "Change state from Approved to:"
  And I set the field "statetype" to "Approved"
  And the "Change state" "button" should be disabled
+
+ @javascript @_switch_window
+ Scenario: Preview question close window.
+ When I am on the "StudentQuiz 1" "mod_studentquiz > View" page logged in as "admin"
+ And I click on "Create new question" "button"
+ And I set the field "item_qtype_truefalse" to "1"
+ And I click on "Add" "button" in the "Choose a question type to add" "dialogue"
+ Then I should see "Adding a True/False question"
+ And I set the field "Question name" to "TF 01"
+ And I set the field "Question text" to "The correct answer is true"
+ And I press "id_submitbutton"
+
+ And I log out
+ And I am on the "StudentQuiz 1" "mod_studentquiz > View" page logged in as "admin"
+ And I choose "Preview" action for "TF 01" in the question bank
+ And I switch to "questionpreview" window
+ And I should see "Close preview"
+ And I click on "Close preview" "button"
+ Then I should see "Create new question"