first commit

question/bank/previewquestion/amd/build/preview.min.js

@@ -0,0 +1,3 @@
+define("qbank_previewquestion/preview",["exports","core_question/question_engine"],(function(_exports,_question_engine){Object.defineProperty(_exports,"__esModule",{value:!0}),_exports.init=void 0;_exports.init=(redirect,url)=>{if(!redirect){document.getElementById("close-previewquestion-page").addEventListener("click",(e=>{e.preventDefault(),null===window.opener?location.href=url:window.close()}))}(0,_question_engine.initForm)("#responseform")}}));
+
+//# sourceMappingURL=preview.min.js.map

question/bank/previewquestion/amd/build/preview.min.js.map

@@ -0,0 +1 @@
+{"version":3,"file":"preview.min.js","sources":["../src/preview.js"],"sourcesContent":["// This file is part of Moodle - http://moodle.org/\n//\n// Moodle is free software: you can redistribute it and/or modify\n// it under the terms of the GNU General Public License as published by\n// the Free Software Foundation, either version 3 of the License, or\n// (at your option) any later version.\n//\n// Moodle is distributed in the hope that it will be useful,\n// but WITHOUT ANY WARRANTY; without even the implied warranty of\n// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the\n// GNU General Public License for more details.\n//\n// You should have received a copy of the GNU General Public License\n// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.\n\n/**\n * Javascript for preview.\n *\n * @module     qbank_previewquestion/preview\n * @copyright  2021 Catalyst IT Australia Pty Ltd\n * @author     Safat Shahin <safatshahin@catalyst-au.net>\n * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later\n */\n\nimport {initForm as initQuestionEngineForm} from 'core_question/question_engine';\n\n/**\n * Set up the actions.\n *\n * @method init\n * @param {bool} redirect Redirect.\n * @param {string} url url to redirect.\n */\nexport const init = (redirect, url) => {\n    if (!redirect) {\n        const closeButton = document.getElementById('close-previewquestion-page');\n        closeButton.addEventListener('click', (e) => {\n            e.preventDefault();\n            if (window.opener === null) {\n                location.href = url;\n            } else {\n                window.close();\n            }\n        });\n    }\n    // Set up the form to be displayed.\n    initQuestionEngineForm('#responseform');\n};\n"],"names":["redirect","url","document","getElementById","addEventListener","e","preventDefault","window","opener","location","href","close"],"mappings":"mNAiCoB,CAACA,SAAUC,WACtBD,SAAU,CACSE,SAASC,eAAe,8BAChCC,iBAAiB,SAAUC,IACnCA,EAAEC,iBACoB,OAAlBC,OAAOC,OACPC,SAASC,KAAOT,IAEhBM,OAAOI,yCAKI"}

question/bank/previewquestion/amd/src/preview.js

@@ -0,0 +1,48 @@
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * Javascript for preview.
+ *
+ * @module     qbank_previewquestion/preview
+ * @copyright  2021 Catalyst IT Australia Pty Ltd
+ * @author     Safat Shahin <safatshahin@catalyst-au.net>
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+import {initForm as initQuestionEngineForm} from 'core_question/question_engine';
+
+/**
+ * Set up the actions.
+ *
+ * @method init
+ * @param {bool} redirect Redirect.
+ * @param {string} url url to redirect.
+ */
+export const init = (redirect, url) => {
+    if (!redirect) {
+        const closeButton = document.getElementById('close-previewquestion-page');
+        closeButton.addEventListener('click', (e) => {
+            e.preventDefault();
+            if (window.opener === null) {
+                location.href = url;
+            } else {
+                window.close();
+            }
+        });
+    }
+    // Set up the form to be displayed.
+    initQuestionEngineForm('#responseform');
+};

question/bank/previewquestion/classes/form/preview_options_form.php

@@ -0,0 +1,106 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+namespace qbank_previewquestion\form;
+
+defined('MOODLE_INTERNAL') || die();
+
+require_once($CFG->libdir . '/formslib.php');
+
+use moodleform;
+use question_display_options;
+use question_engine;
+use qbank_previewquestion\question_preview_options;
+
+/**
+ * Settings form for the preview options.
+ *
+ * @package    qbank_previewquestion
+ * @copyright  2009 The Open University
+ * @author     2021 Safat Shahin <safatshahin@catalyst-au.net>
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class preview_options_form extends moodleform {
+
+    public function definition() {
+        $mform = $this->_form;
+
+        $hiddenorvisible = [
+                question_display_options::HIDDEN => get_string('notshown', 'question'),
+                question_display_options::VISIBLE => get_string('shown', 'question'),
+        ];
+
+        $mform->addElement('header', 'attemptoptionsheader', get_string('previewoptions', 'qbank_previewquestion'));
+        $mform->setExpanded('attemptoptionsheader', false);
+        // Add html element with class to display long text in single line.
+        $mform->addElement('html', \html_writer::div(get_string('theoptionsyouselectonlyaffectthepreview',
+            'qbank_previewquestion'), "col-md-12 row d-flex col-form-label mb-3"));
+        $versions = $this->_customdata['versions'];
+        $versions[question_preview_options::ALWAYS_LATEST] = get_string('alwayslatest', 'qbank_previewquestion');
+        $currentversion = $this->_customdata['restartversion'];
+        $select = $mform->addElement('select', 'restartversion', get_string('questionversion', 'qbank_previewquestion'), $versions);
+        $select->setSelected($currentversion);
+        $behaviours = question_engine::get_behaviour_options(
+                $this->_customdata['quba']->get_preferred_behaviour());
+        $mform->addElement('select', 'behaviour',
+                get_string('howquestionsbehave', 'question'), $behaviours);
+        $mform->addHelpButton('behaviour', 'howquestionsbehave', 'question');
+
+        $mform->addElement('float', 'maxmark', get_string('markedoutof', 'question'), ['size' => '5']);
+
+        if ($this->_customdata['maxvariant'] > 1) {
+            $variants = range(1, $this->_customdata['maxvariant']);
+            $mform->addElement('select', 'variant', get_string('questionvariant', 'question'),
+                    array_combine($variants, $variants));
+        }
+        $mform->setType('variant', PARAM_INT);
+
+        $mform->addElement('submit', 'saverestart',
+                get_string('restartwiththeseoptions', 'question'));
+
+        $mform->addElement('header', 'displayoptionsheader', get_string('displayoptions', 'question'));
+        $mform->setExpanded('displayoptionsheader', false);
+
+        $mform->addElement('select', 'correctness', get_string('whethercorrect', 'question'),
+                $hiddenorvisible);
+
+        $marksoptions = [
+                question_display_options::HIDDEN => get_string('notshown', 'question'),
+                question_display_options::MAX_ONLY => get_string('showmaxmarkonly', 'question'),
+                question_display_options::MARK_AND_MAX => get_string('showmarkandmax', 'question'),
+        ];
+        $mform->addElement('select', 'marks', get_string('marks', 'question'), $marksoptions);
+
+        $mform->addElement('select', 'markdp', get_string('decimalplacesingrades', 'question'),
+                question_engine::get_dp_options());
+
+        $mform->addElement('select', 'feedback',
+                get_string('specificfeedback', 'question'), $hiddenorvisible);
+
+        $mform->addElement('select', 'generalfeedback',
+                get_string('generalfeedback', 'question'), $hiddenorvisible);
+
+        $mform->addElement('select', 'rightanswer',
+                get_string('rightanswer', 'question'), $hiddenorvisible);
+
+        $mform->addElement('select', 'history',
+                get_string('responsehistory', 'question'), $hiddenorvisible);
+
+        $mform->addElement('submit', 'saveupdate',
+                get_string('updatedisplayoptions', 'question'));
+    }
+
+}

question/bank/previewquestion/classes/helper.php

@@ -0,0 +1,339 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+namespace qbank_previewquestion;
+
+defined('MOODLE_INTERNAL') || die();
+
+require_once($CFG->dirroot . '/question/editlib.php');
+
+use action_menu;
+use comment;
+use context_module;
+use context;
+use core\plugininfo\qbank;
+use core_question\local\bank\edit_menu_column;
+use core_question\local\bank\view;
+use core_question\local\bank\question_edit_contexts;
+use moodle_url;
+use question_bank;
+use question_definition;
+use question_display_options;
+use question_engine;
+use stdClass;
+
+/**
+ * Class helper contains all the helper functions.
+ *
+ * @package    qbank_previewquestion
+ * @copyright  2010 The Open University
+ * @author     2021 Safat Shahin <safatshahin@catalyst-au.net>
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class helper {
+
+    /**
+     * Called via pluginfile.php -> question_pluginfile to serve files belonging to
+     * a question in a question_attempt when that attempt is a preview.
+     *
+     * @param stdClass $course course settings object
+     * @param stdClass $context context object
+     * @param string $component the name of the component we are serving files for.
+     * @param string $filearea the name of the file area.
+     * @param int $qubaid the question_usage this image belongs to.
+     * @param int $slot the relevant slot within the usage.
+     * @param array $args the remaining bits of the file path.
+     * @param bool $forcedownload whether the user must be forced to download the file.
+     * @param array $fileoptions options for the stored files
+     * @return void false if file not found, does not return if found - justsend the file
+     */
+    public static function question_preview_question_pluginfile($course, $context, $component,
+            $filearea, $qubaid, $slot, $args, $forcedownload, $fileoptions): void {
+        global $USER, $DB, $CFG;
+
+        list($context, $course, $cm) = get_context_info_array($context->id);
+        require_login($course, false, $cm);
+
+        $quba = question_engine::load_questions_usage_by_activity($qubaid);
+
+        if (!question_has_capability_on($quba->get_question($slot, false), 'use')) {
+            send_file_not_found();
+        }
+
+        $options = new question_display_options();
+        $options->feedback = question_display_options::VISIBLE;
+        $options->numpartscorrect = question_display_options::VISIBLE;
+        $options->generalfeedback = question_display_options::VISIBLE;
+        $options->rightanswer = question_display_options::VISIBLE;
+        $options->manualcomment = question_display_options::VISIBLE;
+        $options->history = question_display_options::VISIBLE;
+        if (!$quba->check_file_access($slot, $options, $component,
+                $filearea, $args, $forcedownload)) {
+            send_file_not_found();
+        }
+
+        $fs = get_file_storage();
+        $relativepath = implode('/', $args);
+        $fullpath = "/{$context->id}/{$component}/{$filearea}/{$relativepath}";
+        if (!$file = $fs->get_file_by_hash(sha1($fullpath)) or $file->is_directory()) {
+            send_file_not_found();
+        }
+
+        send_stored_file($file, 0, 0, $forcedownload, $fileoptions);
+    }
+
+    /**
+     * The the URL to use for actions relating to this preview.
+     *
+     * @param int $questionid the question being previewed
+     * @param int $qubaid the id of the question usage for this preview
+     * @param question_preview_options $options the options in use
+     * @param context $context context for the question preview
+     * @param moodle_url $returnurl url of the page to return to
+     * @param int|null $restartversion version of the question to use when next restarting the preview.
+     * @return moodle_url
+     */
+    public static function question_preview_action_url($questionid, $qubaid,
+            question_preview_options $options, $context, $returnurl = null, $restartversion = null): moodle_url {
+        $params = [
+                'id' => $questionid,
+                'previewid' => $qubaid,
+        ];
+        if ($context->contextlevel == CONTEXT_MODULE) {
+            $params['cmid'] = $context->instanceid;
+        } else if ($context->contextlevel == CONTEXT_COURSE) {
+            $params['courseid'] = $context->instanceid;
+        }
+        if ($returnurl !== null) {
+            $params['returnurl'] = $returnurl;
+        }
+        if ($restartversion !== null) {
+            $params['restartversion'] = $restartversion;
+        }
+        $params = array_merge($params, $options->get_url_params());
+        return new moodle_url('/question/bank/previewquestion/preview.php', $params);
+    }
+
+    /**
+     * The the URL to use for actions relating to this preview.
+     *
+     * @param int $questionid the question being previewed
+     * @param context $context the current moodle context
+     * @param int $previewid optional previewid to sign post saved previewed answers
+     * @param moodle_url $returnurl url of the page to return to
+     * @return moodle_url
+     */
+    public static function question_preview_form_url($questionid, $context, $previewid = null, $returnurl = null): moodle_url {
+        $params = [
+                'id' => $questionid,
+        ];
+        if ($context->contextlevel == CONTEXT_MODULE) {
+            $params['cmid'] = $context->instanceid;
+        } else if ($context->contextlevel == CONTEXT_COURSE) {
+            $params['courseid'] = $context->instanceid;
+        }
+        if ($previewid) {
+            $params['previewid'] = $previewid;
+        }
+        if ($returnurl !== null) {
+            $params['returnurl'] = $returnurl;
+        }
+        return new moodle_url('/question/bank/previewquestion/preview.php', $params);
+    }
+
+    /**
+     * Delete the current preview, if any, and redirect to start a new preview.
+     *
+     * @param int $previewid id of the preview while restarting it
+     * @param int $questionid id of the question in preview
+     * @param object $displayoptions display options for the question in preview
+     * @param object $context context of the question for preview
+     * @param moodle_url $returnurl url of the page to return to
+     * @param int|null $restartversion version of the question to use when next restarting the preview.
+     * @return void
+     */
+    public static function restart_preview($previewid, $questionid, $displayoptions, $context,
+        $returnurl = null, $restartversion = null): void {
+        global $DB;
+
+        if ($previewid) {
+            $transaction = $DB->start_delegated_transaction();
+            question_engine::delete_questions_usage_by_activity($previewid);
+            $transaction->allow_commit();
+        }
+        redirect(self::question_preview_url($questionid, $displayoptions->behaviour,
+                $displayoptions->maxmark, $displayoptions, $displayoptions->variant,
+                $context, $returnurl, $restartversion));
+    }
+
+    /**
+     * Generate the URL for starting a new preview of a given question with the given options.
+     *
+     * @param integer $questionid the question to preview
+     * @param string $preferredbehaviour the behaviour to use for the preview
+     * @param float $maxmark the maximum to mark the question out of
+     * @param question_display_options $displayoptions the display options to use
+     * @param int $variant the variant of the question to preview. If null, one will
+     *      be picked randomly
+     * @param object $context context to run the preview in (affects things like
+     *      filter settings, theme, lang, etc.) Defaults to $PAGE->context
+     * @param moodle_url $returnurl url of the page to return to
+     * @param int $restartversion The version of the question to use when restarting the preview.
+     * @return moodle_url the URL
+     */
+    public static function question_preview_url($questionid, $preferredbehaviour = null,
+            $maxmark = null, $displayoptions = null, $variant = null, $context = null, $returnurl = null,
+            $restartversion = null): moodle_url {
+
+        $params = ['id' => $questionid];
+
+        if (!is_null($restartversion)) {
+            $params['restartversion'] = $restartversion;
+        }
+        if (is_null($context)) {
+            global $PAGE;
+            $context = $PAGE->context;
+        }
+        if ($context->contextlevel == CONTEXT_MODULE) {
+            $params['cmid'] = $context->instanceid;
+        } else if ($context->contextlevel == CONTEXT_COURSE) {
+            $params['courseid'] = $context->instanceid;
+        }
+
+        if (!is_null($preferredbehaviour)) {
+            $params['behaviour'] = $preferredbehaviour;
+        }
+
+        if (!is_null($maxmark)) {
+            $params['maxmark'] = format_float($maxmark, -1);
+        }
+
+        if (!is_null($displayoptions)) {
+            $params['correctness']     = $displayoptions->correctness;
+            $params['marks']           = $displayoptions->marks;
+            $params['markdp']          = $displayoptions->markdp;
+            $params['feedback']        = (bool) $displayoptions->feedback;
+            $params['generalfeedback'] = (bool) $displayoptions->generalfeedback;
+            $params['rightanswer']     = (bool) $displayoptions->rightanswer;
+            $params['history']         = (bool) $displayoptions->history;
+        }
+
+        if (!is_null($returnurl)) {
+            $params['returnurl'] = $returnurl;
+        }
+
+        if ($variant) {
+            $params['variant'] = $variant;
+        }
+
+        return new moodle_url('/question/bank/previewquestion/preview.php', $params);
+    }
+
+    /**
+     * Popup params for the question preview.
+     *
+     * @return array that can be passed as $params to the {@see popup_action} constructor.
+     */
+    public static function question_preview_popup_params(): array {
+        return [
+                'height' => 600,
+                'width' => 800,
+        ];
+    }
+
+    /**
+     * Get the extra elements for preview from qbank plugins.
+     *
+     * @param  question_definition $question question definition object
+     * @param  int $courseid id of the course
+     * @return array
+     */
+    public static function get_preview_extra_elements(question_definition $question, int $courseid): array {
+        $plugins = get_plugin_list_with_function('qbank', 'preview_display');
+
+        $comment = '';
+        $extrahtml = [];
+        foreach ($plugins as $componentname => $plugin) {
+            $pluginhtml = component_callback($componentname, 'preview_display', [$question, $courseid]);
+            if ($componentname === 'qbank_comment') {
+                $comment = $pluginhtml;
+                continue;
+            }
+            $extrahtml[] = $pluginhtml;
+        }
+        return [$comment, $extrahtml];
+    }
+
+    /**
+     * Checks if question is the latest version.
+     *
+     * @param string $version Question version to check
+     * @param string $questionbankentryid Entry to check against
+     * @return bool
+     */
+    public static function is_latest(string $version, string $questionbankentryid): bool {
+        global $DB;
+
+        $sql = 'SELECT MAX(version) AS max
+                  FROM {question_versions}
+                 WHERE questionbankentryid = ?';
+        $latestversion = $DB->get_record_sql($sql, [$questionbankentryid]);
+
+        if (isset($latestversion->max)) {
+            return ($version === $latestversion->max) ? true : false;
+        }
+        return false;
+    }
+
+    /**
+     * Loads question version ids for current question.
+     *
+     * @param  string $questionbankentryid Question bank entry id
+     * @return array  $questionids Array containing question id as key and version as value.
+     */
+    public static function load_versions(string $questionbankentryid): array {
+        global $DB;
+
+        $questionids = [];
+        $sql = 'SELECT version, questionid
+                  FROM {question_versions}
+                 WHERE questionbankentryid = ?
+              ORDER BY version';
+
+        $versions = $DB->get_records_sql($sql, [$questionbankentryid]);
+        foreach ($versions as $key => $version) {
+            $questionids[$version->questionid] = $key;
+        }
+        return $questionids;
+    }
+
+    /**
+     * Return the question ID from the array of id => version that corresponds to the requested version.
+     *
+     * If the requested version is question_preview_options::ALWAYS_LATEST, this will return the latest version.
+     *
+     * @param array $versions
+     * @param int $restartversion
+     * @return ?int
+     */
+    public static function get_restart_id(array $versions, int $restartversion): ?int {
+        if ($restartversion === question_preview_options::ALWAYS_LATEST) {
+            return array_key_last($versions);
+        } else {
+            return array_search($restartversion, $versions) ?: null;
+        }
+    }
+}

question/bank/previewquestion/classes/output/renderer.php

@@ -0,0 +1,70 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+namespace qbank_previewquestion\output;
+
+use context;
+use qbank_previewquestion\helper;
+use qbank_previewquestion\question_preview_options;
+
+/**
+ * Class renderer for rendering preview url
+ *
+ * @package    qbank_previewquestion
+ * @copyright  2009 The Open University
+ * @author     2021 Safat Shahin <safatshahin@catalyst-au.net>
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class renderer extends \plugin_renderer_base {
+
+    /**
+     * Render an icon, optionally with the word 'Preview' beside it, to preview a given question.
+     *
+     * @param int $questionid the id of the question to be previewed.
+     * @param context $context the context in which the preview is happening.
+     *      Must be a course or category context.
+     * @param bool $showlabel if true, show the word 'Preview' after the icon.
+     *      If false, just show the icon.
+     */
+    public function question_preview_link($questionid, context $context, $showlabel) {
+        if ($showlabel) {
+            $alt = '';
+            $label = get_string('preview');
+            $attributes = [];
+        } else {
+            $alt = get_string('preview');
+            $label = '';
+            $attributes = ['title' => $alt];
+        }
+
+        $image = $this->pix_icon('t/preview', $alt, '', ['class' => 'iconsmall']);
+        $link = helper::question_preview_url($questionid, null, null, null, null, $context, null,
+                question_preview_options::ALWAYS_LATEST);
+        $action = new \popup_action('click', $link, 'questionpreview', helper::question_preview_popup_params());
+
+        return $this->action_link($link, $image . $label, $action, $attributes);
+    }
+
+    /**
+     * Render the preview page.
+     *
+     * @param array $previewdata
+     */
+    public function render_preview_page($previewdata) {
+        return $this->render_from_template('qbank_previewquestion/preview_question', $previewdata);
+    }
+
+}

question/bank/previewquestion/classes/plugin_feature.php

@@ -0,0 +1,34 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+namespace qbank_previewquestion;
+
+/**
+ * Class columns is the entrypoint for the columns.
+ *
+ * @package    qbank_previewquestion
+ * @copyright  2021 Catalyst IT Australia Pty Ltd
+ * @author     Safat Shahin <safatshahin@catalyst-au.net>
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class plugin_feature extends \core_question\local\bank\plugin_features_base{
+
+    public function get_question_actions($qbank): array {
+        return [
+            new preview_action($qbank)
+        ];
+    }
+}

question/bank/previewquestion/classes/preview_action.php

@@ -0,0 +1,69 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+namespace qbank_previewquestion;
+
+use core_question\local\bank\question_action_base;
+
+/**
+ * Question bank columns for the preview action icon.
+ *
+ * @package   qbank_previewquestion
+ * @copyright 2009 Tim Hunt
+ * @author    2021 Safat Shahin <safatshahin@catalyst-au.net>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class preview_action extends question_action_base {
+
+    /**
+     * @var string store this lang string for performance.
+     */
+    protected $strpreview;
+
+    public function init(): void {
+        parent::init();
+        $this->strpreview = get_string('preview');
+    }
+
+    public function get_menu_position(): int {
+        return 100;
+    }
+
+    protected function get_url_icon_and_label(\stdClass $question): array {
+        if (!\question_bank::is_qtype_installed($question->qtype)) {
+            // It sometimes happens that people end up with junk questions
+            // in their question bank of a type that is no longer installed.
+            // We cannot do most actions on them, because that leads to errors.
+            return [null, null, null];
+        }
+
+        if (question_has_capability_on($question, 'use')) {
+            $context = $this->qbank->get_most_specific_context();
+            // Default previews to always use the latest question version, unless we are previewing specific versions from the
+            // question history.
+            if ($this->qbank->is_listing_specific_versions()) {
+                $requestedversion = $question->version;
+            } else {
+                $requestedversion = question_preview_options::ALWAYS_LATEST;
+            }
+            $url = helper::question_preview_url($question->id, null, null,
+                                                    null, null, $context, $this->qbank->returnurl, $requestedversion);
+            return [$url, 't/preview', $this->strpreview];
+        } else {
+            return [null, null, null];
+        }
+    }
+}

question/bank/previewquestion/classes/privacy/provider.php

@@ -0,0 +1,32 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+namespace qbank_previewquestion\privacy;
+
+/**
+ * Privacy Subsystem for qbank_previewquestion implementing null_provider.
+ *
+ * @package    qbank_previewquestion
+ * @copyright  2021 Catalyst IT Australia Pty Ltd
+ * @author     Safat Shahin <safatshahin@catalyst-au.net>
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class provider implements \core_privacy\local\metadata\null_provider {
+
+    public static function get_reason(): string {
+        return 'privacy:metadata';
+    }
+}

question/bank/previewquestion/classes/question_preview_options.php

@@ -0,0 +1,144 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+namespace qbank_previewquestion;
+
+use question_display_options;
+
+/**
+ * Displays question preview options as default and set the options.
+ *
+ * Setting default, getting and setting user preferences in question preview options.
+ *
+ * @package    qbank_previewquestion
+ * @copyright  2010 The Open University
+ * @author     2021 Safat Shahin <safatshahin@catalyst-au.net>
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class question_preview_options extends question_display_options {
+
+    /** @var string the behaviour to use for this preview. */
+    public $behaviour;
+
+    /** @var number the maximum mark to use for this preview. */
+    public $maxmark;
+
+    /** @var int the variant of the question to preview. */
+    public $variant;
+
+    /** @var string prefix to append to field names to get user_preference names. */
+    const OPTIONPREFIX = 'question_preview_options_';
+
+    /** @var int Special value for question version ID to indicate that we should always use the latest version */
+    const ALWAYS_LATEST = 0;
+
+    /**
+     * Constructor.
+     * @param \stdClass $question
+     */
+    public function __construct($question) {
+        $this->behaviour = 'deferredfeedback';
+        $this->maxmark = $question->defaultmark;
+        $this->variant = null;
+        $this->correctness = self::VISIBLE;
+        $this->marks = self::MARK_AND_MAX;
+        $this->markdp = get_config('quiz', 'decimalpoints');
+        $this->feedback = self::VISIBLE;
+        $this->numpartscorrect = $this->feedback;
+        $this->generalfeedback = self::VISIBLE;
+        $this->rightanswer = self::VISIBLE;
+        $this->history = self::HIDDEN;
+        $this->flags = self::HIDDEN;
+        $this->manualcomment = self::HIDDEN;
+    }
+
+    /**
+     * Names of the options we store in the user preferences table.
+     * @return array
+     */
+    protected function get_user_pref_fields(): array {
+        return ['behaviour', 'correctness', 'marks', 'markdp', 'feedback', 'generalfeedback', 'rightanswer', 'history'];
+    }
+
+    /**
+     * Names and param types of the options we read from the request.
+     * @return array
+     */
+    protected function get_field_types(): array {
+        return [
+                'behaviour' => PARAM_ALPHA,
+                'maxmark' => PARAM_LOCALISEDFLOAT,
+                'variant' => PARAM_INT,
+                'correctness' => PARAM_BOOL,
+                'marks' => PARAM_INT,
+                'markdp' => PARAM_INT,
+                'feedback' => PARAM_BOOL,
+                'generalfeedback' => PARAM_BOOL,
+                'rightanswer' => PARAM_BOOL,
+                'history' => PARAM_BOOL,
+        ];
+    }
+
+    /**
+     * Load the value of the options from the user_preferences table.
+     */
+    public function load_user_defaults(): void {
+        $defaults = get_config('question_preview');
+        foreach ($this->get_user_pref_fields() as $field) {
+            $this->$field = get_user_preferences(
+                    self::OPTIONPREFIX . $field, $defaults->$field);
+        }
+        $this->numpartscorrect = $this->feedback;
+    }
+
+    /**
+     * Save a change to the user's preview options to the database.
+     * @param object $newoptions
+     */
+    public function save_user_preview_options($newoptions): void {
+        foreach ($this->get_user_pref_fields() as $field) {
+            if (isset($newoptions->$field)) {
+                set_user_preference(self::OPTIONPREFIX . $field, $newoptions->$field);
+            }
+        }
+    }
+
+    /**
+     * Set the value of any fields included in the request.
+     */
+    public function set_from_request(): void {
+        foreach ($this->get_field_types() as $field => $type) {
+            $this->$field = optional_param($field, $this->$field, $type);
+        }
+        $this->numpartscorrect = $this->feedback;
+    }
+
+    /**
+     * Parameters needed in the URL when continuing this preview.
+     *
+     * @return array URL fragment.
+     */
+    public function get_url_params(): array {
+        $params = [];
+        foreach ($this->get_field_types() as $field => $notused) {
+            if ($field === 'behaviour' || $field === 'maxmark' || is_null($this->$field)) {
+                continue;
+            }
+            $params[$field] = $this->$field;
+        }
+        return $params;
+    }
+}

question/bank/previewquestion/lang/en/qbank_previewquestion.php

@@ -0,0 +1,42 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * Strings for component qbank_previewquestion, language 'en'
+ *
+ * @package    qbank_previewquestion
+ * @copyright  2021 Catalyst IT Australia Pty Ltd
+ * @author     Safat Shahin <safatshahin@catalyst-au.net>
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+$string['alwayslatest'] = 'Always latest';
+$string['newerversion'] = 'This preview is using an older version of the question. {$a->restartbutton}';
+$string['pluginname'] = 'Preview question';
+$string['privacy:metadata'] = 'The Preview question question bank plugin does not store any personal data.';
+// Tag related errors.
+$string['tagclosebutton'] = 'Close';
+$string['tagerror'] = 'No question was found with following tags: {$a}. Please change or remove tags filtering.';
+$string['tagsnotfound'] = 'Tags not found';
+// Form string(s).
+$string['previewoptions'] = 'Preview options';
+$string['questionversion'] = 'Question version';
+$string['restartnow'] = 'Use latest version';
+$string['theoptionsyouselectonlyaffectthepreview'] = 'These settings are for testing the question. The options you select only affect the preview.';
+// Preview title.
+$string['versiontitle'] = 'Version {$a}';
+$string['versiontitlelatest'] = 'Version {$a} (latest)';
+

question/bank/previewquestion/lib.php

@@ -0,0 +1,41 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * Callback methods for preview question component
+ *
+ * @package     qbank_previewquestion
+ * @copyright   2023 Paul Holden <paulh@moodle.com>
+ * @license     http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+declare(strict_types=1);
+
+/**
+ * Get the current user preferences that are available
+ *
+ * @return array[]
+ */
+function qbank_previewquestion_user_preferences(): array {
+    return [
+        'core_question_preview_techinfo_collapsed' => [
+            'type' => PARAM_BOOL,
+            'null' => NULL_NOT_ALLOWED,
+            'default' => true,
+            'permissioncallback' => [core_user::class, 'is_current_user'],
+        ],
+    ];
+}

question/bank/previewquestion/preview.php

@@ -0,0 +1,332 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * This page displays a preview of a question
+ *
+ * The preview uses the option settings from the activity within which the question
+ * is previewed or the default settings if no activity is specified. The question session
+ * information is stored in the session as an array of subsequent states rather
+ * than in the database.
+ *
+ * @package    qbank_previewquestion
+ * @copyright  Alex Smith {@link http://maths.york.ac.uk/serving_maths}
+ * @author     2021 Safat Shahin <safatshahin@catalyst-au.net> and numerous contributors.
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+require_once(__DIR__ . '/../../../config.php');
+require_once($CFG->libdir . '/questionlib.php');
+
+use \core\notification;
+use qbank_previewquestion\form\preview_options_form;
+use qbank_previewquestion\question_preview_options;
+use qbank_previewquestion\helper;
+
+/**
+ * The maximum number of variants previewable. If there are more variants than this for a question
+ * then we only allow the selection of the first x variants.
+ *
+ * @var integer
+ */
+define('QUESTION_PREVIEW_MAX_VARIANTS', 100);
+
+\core_question\local\bank\helper::require_plugin_enabled('qbank_previewquestion');
+
+// Get and validate question id.
+$id = required_param('id', PARAM_INT);
+$returnurl = optional_param('returnurl', null, PARAM_LOCALURL);
+$restartversion = optional_param('restartversion', question_preview_options::ALWAYS_LATEST, PARAM_INT);
+
+$question = question_bank::load_question($id);
+
+if ($returnurl) {
+    $returnurl = new moodle_url($returnurl);
+}
+
+// Were we given a particular context to run the question in?
+// This affects things like filter settings, or forced theme or language.
+if ($cmid = optional_param('cmid', 0, PARAM_INT)) {
+    $cm = get_coursemodule_from_id(false, $cmid);
+    require_login($cm->course, false, $cm);
+    $context = context_module::instance($cmid);
+
+} else if ($courseid = optional_param('courseid', 0, PARAM_INT)) {
+    require_login($courseid);
+    $context = context_course::instance($courseid);
+
+} else {
+    require_login();
+    $category = $DB->get_record('question_categories', ['id' => $question->category], '*', MUST_EXIST);
+    $context = context::instance_by_id($category->contextid);
+    $PAGE->set_context($context);
+    // Note that in the other cases, require_login will set the correct page context.
+}
+question_require_capability_on($question, 'use');
+$PAGE->set_pagelayout('popup');
+
+// Get and validate display options.
+$maxvariant = min($question->get_num_variants(), QUESTION_PREVIEW_MAX_VARIANTS);
+$options = new question_preview_options($question);
+$options->load_user_defaults();
+$options->set_from_request();
+$options->versioninfo = false;
+$PAGE->set_url(helper::question_preview_url($id, $options->behaviour, $options->maxmark,
+        $options, $options->variant, $context, null, $restartversion));
+
+// Get and validate existing preview, or start a new one.
+$previewid = optional_param('previewid', 0, PARAM_INT);
+
+if ($previewid) {
+    try {
+        $quba = question_engine::load_questions_usage_by_activity($previewid);
+
+    } catch (Exception $e) {
+        // This may not seem like the right error message to display, but
+        // actually from the user point of view, it makes sense.
+        throw new moodle_exception('submissionoutofsequencefriendlymessage', 'question',
+                helper::question_preview_url($question->id, $options->behaviour,
+                        $options->maxmark, $options, $options->variant, $context, null, $restartversion), null, $e);
+    }
+
+    if ($quba->get_owning_context()->instanceid != $USER->id) {
+        throw new moodle_exception('notyourpreview', 'question');
+    }
+
+    $slot = $quba->get_first_question_number();
+    $usedquestion = $quba->get_question($slot, false);
+    if ($usedquestion->id != $question->id) {
+        throw new moodle_exception('questionidmismatch', 'question');
+    }
+    $question = $usedquestion;
+    $options->variant = $quba->get_variant($slot);
+
+} else {
+    $quba = question_engine::make_questions_usage_by_activity(
+            'core_question_preview', context_user::instance($USER->id));
+    $quba->set_preferred_behaviour($options->behaviour);
+    $slot = $quba->add_question($question, $options->maxmark);
+
+    if ($options->variant) {
+        $options->variant = min($maxvariant, max(1, $options->variant));
+    } else {
+        $options->variant = rand(1, $maxvariant);
+    }
+
+    $quba->start_question($slot, $options->variant);
+
+    $transaction = $DB->start_delegated_transaction();
+    question_engine::save_questions_usage_by_activity($quba);
+    $transaction->allow_commit();
+}
+$options->behaviour = $quba->get_preferred_behaviour();
+$options->maxmark = $quba->get_question_max_mark($slot);
+
+$versionids = helper::load_versions($question->questionbankentryid);
+// Create the settings form, and initialise the fields.
+$optionsform = new preview_options_form(helper::question_preview_form_url($question->id, $context, $previewid, $returnurl),
+        [
+            'quba' => $quba,
+            'maxvariant' => $maxvariant,
+            'versions' => array_combine(array_values($versionids), array_values($versionids)),
+            'restartversion' => $restartversion,
+        ]);
+$optionsform->set_data($options);
+
+// Process change of settings, if that was requested.
+if ($newoptions = $optionsform->get_submitted_data()) {
+    // Set user preferences.
+    $options->save_user_preview_options($newoptions);
+    if (!isset($newoptions->variant)) {
+        $newoptions->variant = $options->variant;
+    }
+    $questionid = helper::get_restart_id($versionids, $restartversion);
+    if (isset($newoptions->saverestart)) {
+        helper::restart_preview($previewid, $questionid, $newoptions, $context, $returnurl, $newoptions->restartversion);
+    }
+}
+
+// Prepare a URL that is used in various places.
+$actionurl = helper::question_preview_action_url($question->id, $quba->get_id(), $options, $context, $returnurl, $restartversion);
+
+// Process any actions from the buttons at the bottom of the form.
+if (data_submitted() && confirm_sesskey()) {
+
+    try {
+
+        if (optional_param('restart', false, PARAM_BOOL)) {
+            $questionid = helper::get_restart_id($versionids, $restartversion);
+            helper::restart_preview($previewid, $questionid, $options, $context, $returnurl, $restartversion);
+
+        } else if (optional_param('fill', null, PARAM_BOOL)) {
+            $correctresponse = $quba->get_correct_response($slot);
+            if (!is_null($correctresponse)) {
+                $quba->process_action($slot, $correctresponse);
+
+                $transaction = $DB->start_delegated_transaction();
+                question_engine::save_questions_usage_by_activity($quba);
+                $transaction->allow_commit();
+            }
+            redirect($actionurl);
+
+        } else if (optional_param('finish', null, PARAM_BOOL)) {
+            $quba->process_all_actions();
+            $quba->finish_all_questions();
+
+            $transaction = $DB->start_delegated_transaction();
+            question_engine::save_questions_usage_by_activity($quba);
+            $transaction->allow_commit();
+            redirect($actionurl);
+
+        } else {
+            $quba->process_all_actions();
+
+            $transaction = $DB->start_delegated_transaction();
+            question_engine::save_questions_usage_by_activity($quba);
+            $transaction->allow_commit();
+
+            $mdlscrollto = optional_param('mdlscrollto', '', PARAM_RAW);
+            if ($mdlscrollto !== '') {
+                $actionurl->param('mdlscrollto', (int) $mdlscrollto);
+            }
+            redirect($actionurl);
+        }
+
+    } catch (question_out_of_sequence_exception $e) {
+        throw new moodle_exception('submissionoutofsequencefriendlymessage', 'question', $actionurl);
+
+    } catch (Exception $e) {
+        // This sucks, if we display our own custom error message, there is no way
+        // to display the original stack trace.
+        $debuginfo = '';
+        if (!empty($e->debuginfo)) {
+            $debuginfo = $e->debuginfo;
+        }
+        throw new moodle_exception('errorprocessingresponses', 'question', $actionurl,
+                $e->getMessage(), $debuginfo);
+    }
+}
+
+if ($question->length) {
+    $displaynumber = '1';
+} else {
+    $displaynumber = 'i';
+}
+$restartdisabled = [];
+$finishdisabled = [];
+$filldisabled = [];
+if ($quba->get_question_state($slot)->is_finished()) {
+    $finishdisabled = ['disabled' => 'disabled'];
+    $filldisabled = ['disabled' => 'disabled'];
+}
+// If question type cannot give us a correct response, disable this button.
+if (is_null($quba->get_correct_response($slot))) {
+    $filldisabled = ['disabled' => 'disabled'];
+}
+if (!$previewid) {
+    $restartdisabled = ['disabled' => 'disabled'];
+}
+
+// Prepare technical info to be output.
+$qa = $quba->get_question_attempt($slot);
+$technical = [];
+$technical[] = get_string('behaviourbeingused', 'question',
+        question_engine::get_behaviour_name($qa->get_behaviour_name()));
+$technical[] = get_string('technicalinfominfraction', 'question', $qa->get_min_fraction());
+$technical[] = get_string('technicalinfomaxfraction', 'question', $qa->get_max_fraction());
+$technical[] = get_string('technicalinfovariant', 'question', $qa->get_variant());
+$technical[] = get_string('technicalinfoquestionsummary', 'question', s($qa->get_question_summary()));
+$technical[] = get_string('technicalinforightsummary', 'question', s($qa->get_right_answer_summary()));
+$technical[] = get_string('technicalinforesponsesummary', 'question', s($qa->get_response_summary()));
+$technical[] = get_string('technicalinfostate', 'question', '' . $qa->get_state());
+
+// Start output.
+$title = get_string('previewquestion', 'question', format_string($question->name));
+$headtags = question_engine::initialise_js() . $quba->render_question_head_html($slot);
+$PAGE->set_title($title);
+$PAGE->set_heading($title);
+echo $OUTPUT->header();
+
+$previewdata = [];
+
+$previewdata['questionicon'] = print_question_icon($question);
+$previewdata['questionidumber'] = $question->idnumber;
+$previewdata['questiontitle'] = $question->name;
+$versioninfo = new \core_question\output\question_version_info($question);
+$previewdata['versiontitle'] = $versioninfo->export_for_template($OUTPUT);
+if ($versioninfo->version !== $versioninfo->latestversion) {
+    if ($restartversion == question_preview_options::ALWAYS_LATEST) {
+        $newerversionparams = (object) [
+            'currentversion' => $question->version,
+            'latestversion' => max($versionids),
+            'restartbutton' => $OUTPUT->render_from_template('qbank_previewquestion/restartbutton', []),
+        ];
+        $newversionurl = clone $actionurl;
+        $newversionurl->param('restart', 1);
+        $previewdata['newerversionurl'] = $newversionurl;
+        $previewdata['newerversion'] = get_string('newerversion', 'qbank_previewquestion', $newerversionparams);
+    }
+}
+
+$previewdata['actionurl'] = $actionurl;
+$previewdata['session'] = sesskey();
+$previewdata['slot'] = $slot;
+// Output of the question.
+$previewdata['question'] = $quba->render_question($slot, $options, $displaynumber);
+$previewdata['restartdisabled'] = html_writer::attributes($restartdisabled);
+$previewdata['finishdisabled'] = html_writer::attributes($finishdisabled);
+$previewdata['filldisabled'] = html_writer::attributes($filldisabled);
+// Output the technical info.
+$previewdata['techinfo'] = print_collapsible_region_start('', 'techinfo', get_string('technicalinfo', 'question'),
+        'core_question_preview_techinfo_collapsed', true, true, $OUTPUT->help_icon('technicalinfo', 'question'));
+foreach ($technical as $info) {
+    $previewdata['techinfo'] .= html_writer::tag('p', $info, ['class' => 'notifytiny']);
+}
+$previewdata['techinfo'] .= print_collapsible_region_end(true);
+
+// Display the settings form.
+$previewdata['options'] = $optionsform->render();
+
+list($comment, $extraelements) = helper::get_preview_extra_elements($question, $COURSE->id);
+
+if (!empty($comment)) {
+    $previewdata['comments'] = $comment;
+}
+
+if (!empty($extraelements)) {
+    $elements = [];
+    foreach ($extraelements as $extraelement) {
+        $element = new stdClass();
+        $element->extrapreviewelements = $extraelement;
+        $elements[] = $element;
+    }
+    $previewdata['extrapreviewelements'] = $elements;
+}
+
+$previewdata['redirect'] = false;
+if (!is_null($returnurl)) {
+    $previewdata['redirect'] = true;
+    $previewdata['redirecturl'] = $returnurl;
+}
+$closeurl = new moodle_url('/question/edit.php', ['courseid' => $COURSE->id]);
+echo $PAGE->get_renderer('qbank_previewquestion')->render_preview_page($previewdata);
+
+// Log the preview of this question.
+$event = \core\event\question_viewed::create_from_question_instance($question, $context);
+$event->trigger();
+
+$PAGE->requires->js_call_amd('qbank_previewquestion/preview', 'init', [$previewdata['redirect'], $closeurl->__toString()]);
+echo $OUTPUT->footer();

question/bank/previewquestion/templates/preview_question.mustache

@@ -0,0 +1,116 @@
+{{!
+    This file is part of Moodle - http://moodle.org/
+
+    Moodle is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    Moodle is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+}}
+{{!
+    @template qbank_previewquestion/preview_question
+
+    The preview page for the question type preview.
+    * actionurl - Url to post to
+    * session - Moodle session
+    * slot - The identifying number of the first question that was added to this usage
+    * question - The html of the actual question from the engine
+    * questionicon - The icon of the question type
+    * questiontitle - The name of the question
+    * versiontitle - The string for displaying the version
+    * questionidumber - The idnumber of the question
+    * restartdisabled - The attributes to enable or disable the button, same for finishdisabled and filldisabled
+    * techinfo - Technical information like fraction, state, behaviour etc
+    * exporttoxml - Link to export the question to xml
+    * redirecturl - Url to the base view
+    * comments - Comments api html
+    * extrapreviewelements - Any plugin implementing the callback and sending extra html to view something in the preview page
+
+    Example context (json):
+    {
+        "actionurl": "/",
+        "session": "E2PwCfrnzz",
+        "slot": "1",
+        "question": "<div>question html</div>",
+        "questionicon": "<i class='icon fa fa-search-plus fa-fw' title='Preview question' aria-label='Preview question'></i>",
+        "questiontitle": "Question title",
+        "versiontitle": {
+            "versioninfo": "Version 3 (latest)"
+        },
+        "questionidumber": "qidnumber1",
+        "restartdisabled": "disabled='disabled'",
+        "finishdisabled": "disabled='disabled'",
+        "filldisabled": "disabled='disabled'",
+        "techinfo": "<div>Behaviour being used: Deferred feedback</div>",
+        "redirecturl": "/",
+        "exporttoxml": "Download this question in Moodle XML format",
+        "comments": "html from comments api",
+        "extrapreviewelements": "<div>callback to get html from plugins need to show info in preview</div>"
+    }
+}}
+<form id="responseform" method="post" action="{{{actionurl}}}" enctype="multipart/form-data" autocomplete="off">
+    <div class="d-flex">
+        <h2 class="mt-2">{{{questionicon}}}</h2>
+        <h2 class="ml-2 mt-2"> {{questiontitle}}</h2>
+        <h3 class="px-2 py-1 ml-2 mt-2">
+            {{#versiontitle}}
+                {{>core_question/question_version_info}}
+            {{/versiontitle}}
+        </h3>
+    </div>
+    {{#newerversion}}
+    <div class="alert alert-primary">
+        {{{newerversion}}}
+    </div>
+    {{/newerversion}}
+    <div class="d-flex">
+        <div class="bg-primary text-white h-50 px-2 mt-n2">
+            <span class="accesshide">ID number</span>
+            {{questionidumber}}
+        </div>
+    </div>
+    <br>
+    <div>
+        <input type="hidden" name="sesskey" value="{{session}}">
+        <input type="hidden" name="slots" value="{{slot}}">
+        <input type="hidden" name="scrollpos" value="" id="scrollpos">
+    </div>
+    {{{question}}}
+    <div id="previewcontrols" class="controls input-group">
+        <input type="submit" name="restart" value="{{#str}} restart, question{{/str}}" class="btn btn-secondary mr-1 mb-1" id="id_restart_question_preview" {{{restartdisabled}}}>
+        <input type="submit" name="save" value="{{#str}} save, question{{/str}}" class="btn btn-secondary mr-1 mb-1" id="id_save_question_preview" {{{finishdisabled}}}>
+        <input type="submit" name="fill" value="{{#str}} fillincorrect, question{{/str}}" class="btn btn-secondary mr-1 mb-1" {{{filldisabled}}}>
+        <input type="submit" name="finish" value="{{#str}} submitandfinish, question{{/str}}" class="btn btn-secondary mr-1 mb-1" id="id_finish_question_preview" {{{finishdisabled}}}>
+        {{^redirect}}
+            <input type="button" name="close" value="{{#str}} closepreview, question{{/str}}" class="btn btn-secondary mr-1 mb-1" id="close-previewquestion-page">
+        {{/redirect}}
+        {{#redirect}}
+            <a href="{{{redirecturl}}}" class="btn btn-secondary mr-1 mb-1" role="button">{{#str}} closepreview, question{{/str}}</a>
+        {{/redirect}}
+    </div>
+</form>
+<br>
+{{#comments}}
+    <a data-toggle="collapse" href="#commentcollapse" role="button" aria-expanded="false" aria-controls="commentcollapse">
+        {{#pix}} t/collapsed, core {{/pix}}
+        {{#str}} commentplural, qbank_comment{{/str}}
+    </a>
+    <div class="collapse" id="commentcollapse">
+        {{{comments}}}
+    </div>
+    {{{options}}}
+{{/comments}}
+{{^comments}}
+    {{{options}}}
+{{/comments}}
+{{{techinfo}}}
+{{#extrapreviewelements}}
+    {{{extrapreviewelements}}}
+{{/extrapreviewelements}}

question/bank/previewquestion/templates/restartbutton.mustache

@@ -0,0 +1,27 @@
+{{!
+    This file is part of Moodle - http://moodle.org/
+
+    Moodle is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    Moodle is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+}}
+{{!
+    @template qbank_previewquestion/restartbutton
+
+    A button to restart the preview.
+
+    Example context (json):
+    {
+    }
+}}
+<input type="submit" name="restart" value="{{#str}}restartnow, qbank_previewquestion{{/str}}"
+       class="btn btn-secondary" id="id_restartnow_question_preview">

question/bank/previewquestion/tests/behat/preview_question.feature

@@ -0,0 +1,169 @@
+@qbank @qbank_previewquestion
+Feature: A teacher can preview questions in the question bank
+  In order to ensure the questions are properly created
+  As a teacher
+  I need to preview the questions
+
+  Background:
+    Given the following "users" exist:
+      | username | firstname | lastname | email            |
+      | teacher1 | Teacher   | 1        | teacher1@example.com |
+    And the following "courses" exist:
+      | fullname | shortname | format |
+      | Course 1 | C1        | weeks  |
+    And the following "activities" exist:
+      | activity   | name      | course | idnumber |
+      | quiz       | Test quiz | C1     | quiz1    |
+    And the following "course enrolments" exist:
+      | user     | course | role           |
+      | teacher1 | C1     | editingteacher |
+    And the following "question categories" exist:
+      | contextlevel | reference | name           |
+      | Course       | C1        | Test questions |
+    And the following "questions" exist:
+      | questioncategory | qtype     | name                          |
+      | Test questions   | numerical | Test question to be previewed |
+    And I am on the "Test quiz" "mod_quiz > question bank" page logged in as "teacher1"
+    When I choose "Preview" action for "Test question to be previewed" in the question bank
+
+  Scenario: Question preview shows the question and other information
+    Then the state of "What is pi to two d.p.?" question is shown as "Not yet answered"
+    And I should see "(latest)"
+    And I should see "Marked out of 1.00"
+    And I should see "Technical information"
+    And I should see "Display options"
+    And I should see "Preview options"
+    And I should see "Comments"
+    And I click on "Comments" "link"
+    And I should see "Save comment"
+    And I should see "ID number"
+    And "Numerical" "icon" should exist
+    And I should see "Version"
+    And I click on "Preview options" "link"
+    And I should see "These settings are for testing the question. The options you select only affect the preview."
+    And I should see "Question version"
+
+  Scenario: Preview lets the teacher see what happens when an answer is saved
+    When I set the field "Answer:" to "1"
+    And I press "Save"
+    Then the state of "What is pi to two d.p.?" question is shown as "Answer saved"
+
+  Scenario: Preview lets the teacher see what happens when an answer is submitted
+    When I set the field "Answer:" to "3.14"
+    And I press "Submit and finish"
+    Then the state of "What is pi to two d.p.?" question is shown as "Correct"
+
+  Scenario: Preview lets the teacher see what happens with different review options
+    Given I set the field "Answer:" to "3.14"
+    And I press "Submit and finish"
+    And I press "Display options"
+    When I set the field "Whether correct" to "Not shown"
+    And I set the field "Decimal places in grades" to "5"
+    And I press "Update display options"
+    And I set the field "Answer:" to "3.14"
+    And I press "Submit and finish"
+    Then the state of "What is pi to two d.p.?" question is shown as "Complete"
+    And I should see "1.00000"
+
+  Scenario: Preview lets the teacher see what happens with different behaviours
+    When I press "Preview options"
+    And I set the field "How questions behave" to "Immediate feedback"
+    And I set the field "Marked out of" to "3"
+    And I press "Save preview options and start again"
+    And I set the field "Answer:" to "3.1"
+    And I press "Check"
+    Then the state of "What is pi to two d.p.?" question is shown as "Incorrect"
+    And I should see "Mark 0.00 out of 3.00"
+    And I should see "Not accurate enough."
+
+  Scenario: Preview lets the teacher "Start again" while previewing
+    Given I set the field "Answer:" to "1"
+    And I press "Submit and finish"
+    When I press "Start again"
+    Then the state of "What is pi to two d.p.?" question is shown as "Not yet answered"
+
+  Scenario: Preview lets the teacher "Fill in correct response" while previewing
+    When I press "Fill in correct responses"
+    Then the field "Answer:" matches value "3.14"
+
+  Scenario: Preview a question with very small grade
+    When I press "Preview options"
+    And I set the field "Marked out of" to "0.00000123456789"
+    And I press "Save preview options and start again"
+    Then the field "Marked out of" matches value "0.00000123456789"
+
+  Scenario: Question version is updated when edited and teacher can change question version
+    Given I should see "Version 1"
+    And I press "Close preview"
+    And I choose "Edit question" action for "Test question to be previewed" in the question bank
+    And I set the field "Question name" to "New version"
+    And I set the field "Question text" to "New text version"
+    And I click on "submitbutton" "button"
+    And I choose "Preview" action for "New version" in the question bank
+    When I expand all fieldsets
+    And I should see "Version 2"
+    And I should see "(latest)"
+    And I should see "New version"
+    And I should see "New text version"
+    And I should not see "Test question to be previewed"
+    And I should not see "Version 1"
+    And I should see "1" in the "Question version" "select"
+    And I should see "2" in the "Question version" "select"
+    And I set the field "Question version" to "1"
+    And I press "Save preview options and start again"
+    Then I should see "Version 1"
+    And I should not see "Version 2"
+    And I should not see "(latest)"
+
+  Scenario: The preview always uses the latest question version by default.
+    Given the following "core_question > updated questions" exist:
+      | questioncategory | question                      | questiontext       |
+      | Test questions   | Test question to be previewed | Question version 2 |
+    And I should see "Version 1 (latest)"
+    And I expand all fieldsets
+    And the field "Question version" matches value "Always latest"
+    And I set the field "Answer:" to "3.14"
+    And I press "Submit and finish"
+    And I should see "Version 1"
+    When I press "Start again"
+    Then I should not see "Version 1"
+    And I should see "Version 2 (latest)"
+
+  Scenario: Detect a newer version during always latest preview and offer to switch to the latest
+    Given I should not see "This preview is using version 1"
+    And the following "core_question > updated questions" exist:
+      | questioncategory | question                      | questiontext       |
+      | Test questions   | Test question to be previewed | Question version 2 |
+    And I should see "Version 1 (latest)"
+    And I set the field "Answer:" to "3.14"
+    When I press "Submit and finish"
+    And I should see "This preview is using an older version of the question."
+    And I press "Use latest version"
+    Then I should not see "Version 1"
+    And I should see "Version 2 (latest)"
+
+  Scenario: Previewing from the question history will not always show the latest version
+    Given I press "Close preview"
+    And the following "core_question > updated questions" exist:
+      | questioncategory | question                      | questiontext       |
+      | Test questions   | Test question to be previewed | Question version 2 |
+    And I choose "History" action for "Test question to be previewed" in the question bank
+    And I choose "Preview" action for "Test question to be previewed" in the question bank
+    And I should see "Version 1 (of 2)"
+    And I expand all fieldsets
+    And the field "Question version" matches value "1"
+    And I set the field "Answer:" to "3.14"
+    And I press "Submit and finish"
+    And I should see "Version 1 (of 2)"
+    And I should not see "The latest version is 2."
+    And the following "core_question > updated questions" exist:
+      | questioncategory | question                      | questiontext       |
+      | Test questions   | Test question to be previewed | Question version 3 |
+    When I press "Start again"
+    Then I should see "Version 1 (of 3)"
+    And I should not see "Version 3 (latest)"
+
+  Scenario: Question preview can be closed
+    And I press "Close preview"
+    Then I should not see "(latest)"
+    And I should see "Test quiz"

question/bank/previewquestion/tests/behat/preview_question_action.feature

@@ -0,0 +1,43 @@
+@qbank @qbank_previewquestion
+Feature: Use the qbank plugin manager page for previewquestion
+  In order to check the plugin behaviour with enable and disable
+
+  Background:
+    Given the following "courses" exist:
+      | fullname | shortname | category |
+      | Course 1 | C1        | 0        |
+    And the following "activities" exist:
+      | activity   | name      | course | idnumber |
+      | quiz       | Test quiz | C1     | quiz1    |
+    And the following "question categories" exist:
+      | contextlevel | reference | name           |
+      | Course         | C1     | Test questions |
+    And the following "questions" exist:
+      | questioncategory | qtype     | name           | questiontext              |
+      | Test questions   | truefalse | First question | Answer the first question |
+
+  Scenario: Enable/disable previewquestion column from the base view
+    Given I log in as "admin"
+    When I navigate to "Plugins > Question bank plugins > Manage question bank plugins" in site administration
+    And I should see "Preview question"
+    And I click on "Disable" "link" in the "Preview question" "table_row"
+    And I am on the "Test quiz" "mod_quiz > question bank" page
+    Then the "Preview" item should not exist in the "Edit" action menu of the "First question" "table_row"
+    And I navigate to "Plugins > Question bank plugins > Manage question bank plugins" in site administration
+    And I click on "Enable" "link" in the "Preview question" "table_row"
+    And I am on the "Test quiz" "mod_quiz > question bank" page
+    And the "Preview" item should exist in the "Edit" action menu of the "First question" "table_row"
+
+  Scenario: Enable/disable preview button from question edit form
+    Given I log in as "admin"
+    When I navigate to "Plugins > Question bank plugins > Manage question bank plugins" in site administration
+    And I should see "Preview question"
+    And I click on "Disable" "link" in the "Preview question" "table_row"
+    And I am on the "Test quiz" "mod_quiz > question bank" page
+    And I choose "Edit question" action for "First question" in the question bank
+    Then I should not see "Preview" in the "region-main" "region"
+    And I navigate to "Plugins > Question bank plugins > Manage question bank plugins" in site administration
+    And I click on "Enable" "link" in the "Preview question" "table_row"
+    And I am on the "Test quiz" "mod_quiz > question bank" page
+    And I choose "Edit question" action for "First question" in the question bank
+    And I should see "Preview" in the "region-main" "region"

question/bank/previewquestion/tests/qbank_preview_helper_test.php

@@ -0,0 +1,271 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+namespace qbank_previewquestion;
+
+use context_course;
+use moodle_url;
+use core\plugininfo\qbank;
+use question_bank;
+use question_engine;
+use stdClass;
+
+/**
+ * Helper tests for question preview.
+ *
+ * @package    qbank_previewquestion
+ * @copyright  2021 Catalyst IT Australia Pty Ltd
+ * @author     Safat Shahin <safatshahin@catalyst-au.net>
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ * @coversDefaultClass \qbank_previewquestion\helper
+ */
+class qbank_preview_helper_test extends \advanced_testcase {
+
+    /**
+     * @var bool|\context|\context_course $context
+     */
+    public $context;
+
+    /**
+     * @var object $questiondata;
+     */
+    public $questiondata;
+
+    /**
+     * @var \question_usage_by_activity $quba
+     */
+    public $quba;
+
+    /**
+     * @var question_preview_options $options
+     */
+    public $options;
+
+    /**
+     * @var \moodle_url $returnurl
+     */
+    public $returnurl;
+
+    /**
+     * Test set up.
+     *
+     * This is executed before running any test in this file.
+     */
+    public function setUp(): void {
+        global $USER;
+        $this->resetAfterTest();
+        $this->setAdminUser();
+        $generator = $this->getDataGenerator();
+        $questiongenerator = $generator->get_plugin_generator('core_question');
+        // Create a course.
+        $course = $generator->create_course();
+        $this->context = context_course::instance($course->id);
+        // Create a question in the default category.
+        $contexts = new \core_question\local\bank\question_edit_contexts($this->context);
+        $cat = question_make_default_categories($contexts->all());
+        $this->questiondata = $questiongenerator->create_question('numerical', null,
+                ['name' => 'Example question', 'category' => $cat->id]);
+        $this->quba = question_engine::make_questions_usage_by_activity('core_question_preview',
+            \context_user::instance($USER->id));
+        $this->options = new question_preview_options($this->questiondata);
+        $this->options->load_user_defaults();
+        $this->options->set_from_request();
+        $this->returnurl = new moodle_url('/question/edit.php');
+    }
+
+    /**
+     * Test the preview action url from the helper class.
+     *
+     * @covers ::question_preview_action_url
+     */
+    public function test_question_preview_action_url(): void {
+        $actionurl = helper::question_preview_action_url($this->questiondata->id, $this->quba->get_id(), $this->options,
+                $this->context, $this->returnurl, question_preview_options::ALWAYS_LATEST);
+        $params = [
+           'id' => $this->questiondata->id,
+           'previewid' => $this->quba->get_id(),
+           'returnurl' => $this->returnurl,
+           'courseid' => $this->context->instanceid,
+           'restartversion' => question_preview_options::ALWAYS_LATEST,
+        ];
+        $params = array_merge($params, $this->options->get_url_params());
+        $expectedurl = new moodle_url('/question/bank/previewquestion/preview.php', $params);
+        $this->assertEquals($expectedurl, $actionurl);
+    }
+
+    /**
+     * Test the preview action url from the helper class when no restartversion is passed.
+     *
+     * @covers ::question_preview_action_url
+     */
+    public function test_question_preview_action_url_no_restartversion(): void {
+        $actionurl = helper::question_preview_action_url($this->questiondata->id, $this->quba->get_id(), $this->options,
+                $this->context, $this->returnurl);
+        $params = [
+            'id' => $this->questiondata->id,
+            'previewid' => $this->quba->get_id(),
+            'returnurl' => $this->returnurl,
+            'courseid' => $this->context->instanceid
+        ];
+        $params = array_merge($params, $this->options->get_url_params());
+        $expectedurl = new moodle_url('/question/bank/previewquestion/preview.php', $params);
+        $this->assertEquals($expectedurl, $actionurl);
+    }
+
+    /**
+     * Test the preview form url from the helper class.
+     *
+     * @covers ::question_preview_form_url
+     */
+    public function test_question_preview_form_url(): void {
+        $formurl = helper::question_preview_form_url(
+                $this->questiondata->id, $this->context, $this->quba->get_id(), $this->returnurl);
+        $params = [
+            'id' => $this->questiondata->id,
+            'previewid' => $this->quba->get_id(),
+            'returnurl' => $this->returnurl,
+            'courseid' => $this->context->instanceid
+        ];
+        $expectedurl = new moodle_url('/question/bank/previewquestion/preview.php', $params);
+        $this->assertEquals($expectedurl, $formurl);
+    }
+
+    /**
+     * Test the preview url from the helper class.
+     *
+     * @covers ::question_preview_url
+     */
+    public function test_question_preview_url(): void {
+        $previewurl = helper::question_preview_url($this->questiondata->id, $this->options->behaviour, $this->options->maxmark,
+                $this->options, $this->options->variant, $this->context, null, question_preview_options::ALWAYS_LATEST);
+        $params = [
+            'id' => $this->questiondata->id,
+            'behaviour' => $this->options->behaviour,
+            'maxmark' => $this->options->maxmark,
+            'courseid' => $this->context->instanceid,
+            'restartversion' => question_preview_options::ALWAYS_LATEST,
+        ];
+        // Extra params for options.
+        $params['correctness']     = $this->options->correctness;
+        $params['marks']           = $this->options->marks;
+        $params['markdp']          = $this->options->markdp;
+        $params['feedback']        = (bool) $this->options->feedback;
+        $params['generalfeedback'] = (bool) $this->options->generalfeedback;
+        $params['rightanswer']     = (bool) $this->options->rightanswer;
+        $params['history']         = (bool) $this->options->history;
+        $expectedurl = new moodle_url('/question/bank/previewquestion/preview.php', $params);
+        $this->assertEquals($expectedurl, $previewurl);
+    }
+
+
+    /**
+     * Test the preview url from the helper class.
+     *
+     * @covers ::question_preview_url
+     */
+    public function test_question_preview_url_no_restartversion(): void {
+        $previewurl = helper::question_preview_url($this->questiondata->id, $this->options->behaviour, $this->options->maxmark,
+                $this->options, $this->options->variant, $this->context, null);
+        $params = [
+            'id' => $this->questiondata->id,
+            'behaviour' => $this->options->behaviour,
+            'maxmark' => $this->options->maxmark,
+            'courseid' => $this->context->instanceid,
+        ];
+        // Extra params for options.
+        $params['correctness']     = $this->options->correctness;
+        $params['marks']           = $this->options->marks;
+        $params['markdp']          = $this->options->markdp;
+        $params['feedback']        = (bool) $this->options->feedback;
+        $params['generalfeedback'] = (bool) $this->options->generalfeedback;
+        $params['rightanswer']     = (bool) $this->options->rightanswer;
+        $params['history']         = (bool) $this->options->history;
+        $expectedurl = new moodle_url('/question/bank/previewquestion/preview.php', $params);
+        $this->assertEquals($expectedurl, $previewurl);
+    }
+
+    /**
+     * Test the preview comment callback if available.
+     *
+     * @covers ::get_preview_extra_elements
+     */
+    public function test_get_preview_extra_elements(): void {
+        global $PAGE;
+        $PAGE->set_url('/');
+
+        $question = \question_bank::load_question($this->questiondata->id);
+        list($comment, $extraelements) = helper::get_preview_extra_elements($question, $this->context->instanceid);
+        if (qbank::is_plugin_enabled('qbank_comment')) {
+            $this->assertStringContainsString("comment-area", $comment);
+        } else {
+            $this->assertEquals('', $comment);
+        }
+    }
+
+    /**
+     * Test method load_versions().
+     *
+     * @covers ::load_versions
+     */
+    public function test_load_versions(): void {
+        $this->resetAfterTest();
+
+        $generator = $this->getDataGenerator()->get_plugin_generator('core_question');
+        $qcat1 = $generator->create_question_category(['name' => 'My category', 'sortorder' => 1, 'idnumber' => 'myqcat']);
+        $questiongenerated = $generator->create_question('description', null, ['name' => 'q1', 'category' => $qcat1->id]);
+
+        $qtypeobj = question_bank::get_qtype($questiongenerated->qtype);
+        $question = question_bank::load_question($questiongenerated->id);
+        $versionids = helper::load_versions($question->questionbankentryid);
+        $this->assertEquals([
+            $question->id => 1,
+        ], $versionids);
+
+        $fromform = new stdClass();
+        $fromform->name = 'Name edited';
+        $fromform->category = $qcat1->id;
+        $questiontwo = $qtypeobj->save_question($questiongenerated, $fromform);
+        $versionids = helper::load_versions($question->questionbankentryid);
+        $this->assertSame([
+            $question->id => 1,
+            $questiontwo->id => 2,
+        ], $versionids);
+    }
+
+    /**
+     * Test method get_restart_id().
+     *
+     * This should return the value of the specified version number, or the latest version if ALWAYS_LATEST is passed.
+     *
+     * @covers ::get_restart_id
+     * @return void
+     */
+    public function test_get_restart_id(): void {
+        $versions = [
+            100 => 1,
+            200 => 2,
+            300 => 3
+        ];
+
+        $this->assertEquals(100, helper::get_restart_id($versions, 1));
+        $this->assertEquals(200, helper::get_restart_id($versions, 2));
+        $this->assertEquals(300, helper::get_restart_id($versions, 3));
+        $this->assertEquals(300, helper::get_restart_id($versions, question_preview_options::ALWAYS_LATEST));
+        $this->assertNull(helper::get_restart_id($versions, 4));
+        $this->assertNull(helper::get_restart_id([], 1));
+        $this->assertNull(helper::get_restart_id([], question_preview_options::ALWAYS_LATEST));
+    }
+}

question/bank/previewquestion/version.php

@@ -0,0 +1,31 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * Version information for qbank_previewquestion.
+ *
+ * @package    qbank_previewquestion
+ * @copyright  2021 Catalyst IT Australia Pty Ltd
+ * @author     Safat Shahin <safatshahin@catalyst-au.net>
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+defined('MOODLE_INTERNAL') || die();
+
+$plugin->component = 'qbank_previewquestion';
+$plugin->version   = 2024042200;
+$plugin->requires  = 2024041600;
+$plugin->maturity  = MATURITY_STABLE;