Preview window add "Close preview" button fix #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"