Proyectos de Subversion Moodle

<?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 file contains helper classes for testing the question engine.

 *

 * @package    moodlecore

 * @subpackage questionengine

 * @copyright  2009 The Open University

 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

 */

defined('MOODLE_INTERNAL') || die();

global $CFG;

require_once(__DIR__ . '/../lib.php');

require_once($CFG->dirroot . '/lib/phpunit/lib.php');

/**

 * Makes some protected methods of question_attempt public to facilitate testing.

 *

 * @copyright  2009 The Open University

 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

 */

class testable_question_attempt extends question_attempt {

    public function add_step(question_attempt_step $step) {

        parent::add_step($step);

    }

    public function set_min_fraction($fraction) {

        $this->minfraction = $fraction;

    }

    public function set_max_fraction($fraction) {

        $this->maxfraction = $fraction;

    }

    public function set_behaviour(question_behaviour $behaviour) {

        $this->behaviour = $behaviour;

    }

}

/**

 * Test subclass to allow access to some protected data so that the correct

 * behaviour can be verified.

 *

 * @copyright  2012 The Open University

 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

 */

class testable_question_engine_unit_of_work extends question_engine_unit_of_work {

    public function get_modified() {

        return $this->modified;

    }

    public function get_attempts_added() {

        return $this->attemptsadded;

    }

    public function get_attempts_modified() {

        return $this->attemptsmodified;

    }

    public function get_steps_added() {

        return $this->stepsadded;

    }

    public function get_steps_modified() {

        return $this->stepsmodified;

    }

    public function get_steps_deleted() {

        return $this->stepsdeleted;

    }

    public function get_metadata_added() {

        return $this->metadataadded;

    }

    public function get_metadata_modified() {

        return $this->metadatamodified;

    }

}

/**

 * Base class for question type test helpers.

 *

 * @copyright  2011 The Open University

 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

 */

abstract class question_test_helper {

    /**

     * @return array of example question names that can be passed as the $which

     * argument of {@link test_question_maker::make_question} when $qtype is

     * this question type.

     */

    abstract public function get_test_questions();

    /**

     * Set up a form to create a question in $cat. This method also sets cat and contextid on $questiondata object.

     * @param object $cat the category

     * @param object $questiondata form initialisation requires question data.

     * @return moodleform

     */

    public static function get_question_editing_form($cat, $questiondata) {

        $catcontext = context::instance_by_id($cat->contextid, MUST_EXIST);

        $contexts = new core_question\local\bank\question_edit_contexts($catcontext);

        $dataforformconstructor = new stdClass();

        $dataforformconstructor->createdby = $questiondata->createdby;

        $dataforformconstructor->qtype = $questiondata->qtype;

        $dataforformconstructor->contextid = $questiondata->contextid = $catcontext->id;

        $dataforformconstructor->category = $questiondata->category = $cat->id;

        $dataforformconstructor->status = $questiondata->status;

        $dataforformconstructor->formoptions = new stdClass();

        $dataforformconstructor->formoptions->canmove = true;

        $dataforformconstructor->formoptions->cansaveasnew = true;

        $dataforformconstructor->formoptions->canedit = true;

        $dataforformconstructor->formoptions->repeatelements = true;

        $qtype = question_bank::get_qtype($questiondata->qtype);

        return  $qtype->create_editing_form('question.php', $dataforformconstructor, $cat, $contexts, true);

    }

}

/**

 * This class creates questions of various types, which can then be used when

 * testing.

 *

 * @copyright  2009 The Open University

 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

 */

class test_question_maker {

    const STANDARD_OVERALL_CORRECT_FEEDBACK = 'Well done!';

    const STANDARD_OVERALL_PARTIALLYCORRECT_FEEDBACK =

        'Parts, but only parts, of your response are correct.';

    const STANDARD_OVERALL_INCORRECT_FEEDBACK = 'That is not right at all.';

    /** @var array qtype => qtype test helper class. */

    protected static $testhelpers = array();

    /**

     * Just make a question_attempt at a question. Useful for unit tests that

     * need to pass a $qa to methods that call format_text. Probably not safe

     * to use for anything beyond that.

     * @param question_definition $question a question.

     * @param number $maxmark the max mark to set.

     * @return question_attempt the question attempt.

     */

    public static function get_a_qa($question, $maxmark = 3) {

        return new question_attempt($question, 13, null, $maxmark);

    }

    /**

     * Initialise the common fields of a question of any type.

     */

    public static function initialise_a_question($q) {

        global $USER;

        $q->id = 0;

        $q->category = 0;

        $q->idnumber = null;

        $q->parent = 0;

        $q->questiontextformat = FORMAT_HTML;

        $q->generalfeedbackformat = FORMAT_HTML;

        $q->defaultmark = 1;

        $q->penalty = 0.3333333;

        $q->length = 1;

        $q->stamp = make_unique_id_code();

        $q->status = \core_question\local\bank\question_version_status::QUESTION_STATUS_READY;

        $q->version = 1;

        $q->timecreated = time();

        $q->timemodified = time();

        $q->createdby = $USER->id;

        $q->modifiedby = $USER->id;

    }

    public static function initialise_question_data($qdata) {

        global $USER;

        $qdata->id = 0;

        $qdata->category = 0;

        $qdata->idnumber = null;

        $qdata->contextid = 0;

        $qdata->parent = 0;

        $qdata->questiontextformat = FORMAT_HTML;

        $qdata->generalfeedbackformat = FORMAT_HTML;

        $qdata->defaultmark = 1;

        $qdata->penalty = 0.3333333;

        $qdata->length = 1;

        $qdata->stamp = make_unique_id_code();

        $qdata->status = \core_question\local\bank\question_version_status::QUESTION_STATUS_READY;

        $qdata->version = 1;

        $qdata->timecreated = time();

        $qdata->timemodified = time();

        $qdata->createdby = $USER->id;

        $qdata->modifiedby = $USER->id;

        $qdata->hints = array();

    }

    /**

     * Get the test helper class for a particular question type.

     * @param $qtype the question type name, e.g. 'multichoice'.

     * @return question_test_helper the test helper class.

     */

    public static function get_test_helper($qtype) {

        global $CFG;

        if (array_key_exists($qtype, self::$testhelpers)) {

            return self::$testhelpers[$qtype];

        }

        $file = core_component::get_plugin_directory('qtype', $qtype) . '/tests/helper.php';

        if (!is_readable($file)) {

            throw new coding_exception('Question type ' . $qtype .

                ' does not have test helper code.');

        }

        include_once($file);

        $class = 'qtype_' . $qtype . '_test_helper';

        if (!class_exists($class)) {

            throw new coding_exception('Class ' . $class . ' is not defined in ' . $file);

        }

        self::$testhelpers[$qtype] = new $class();

        return self::$testhelpers[$qtype];

    }

    /**

     * Call a method on a qtype_{$qtype}_test_helper class and return the result.

     *

     * @param string $methodtemplate e.g. 'make_{qtype}_question_{which}';

     * @param string $qtype the question type to get a test question for.

     * @param string $which one of the names returned by the get_test_questions

     *      method of the relevant qtype_{$qtype}_test_helper class.

     * @param unknown_type $which

     */

    protected static function call_question_helper_method($methodtemplate, $qtype, $which = null) {

        $helper = self::get_test_helper($qtype);

        $available = $helper->get_test_questions();

        if (is_null($which)) {

            $which = reset($available);

        } else if (!in_array($which, $available)) {

            throw new coding_exception('Example question ' . $which . ' of type ' .

                $qtype . ' does not exist.');

        }

        $method = str_replace(array('{qtype}', '{which}'),

            array($qtype,    $which), $methodtemplate);

        if (!method_exists($helper, $method)) {

            throw new coding_exception('Method ' . $method . ' does not exist on the ' .

                $qtype . ' question type test helper class.');

        }

        return $helper->$method();

    }

    /**

     * Question types can provide a number of test question defintions.

     * They do this by creating a qtype_{$qtype}_test_helper class that extends

     * question_test_helper. The get_test_questions method returns the list of

     * test questions available for this question type.

     *

     * @param string $qtype the question type to get a test question for.

     * @param string $which one of the names returned by the get_test_questions

     *      method of the relevant qtype_{$qtype}_test_helper class.

     * @return question_definition the requested question object.

     */

    public static function make_question($qtype, $which = null) {

        return self::call_question_helper_method('make_{qtype}_question_{which}',

            $qtype, $which);

    }

    /**

     * Like {@link make_question()} but returns the datastructure from

     * get_question_options instead of the question_definition object.

     *

     * @param string $qtype the question type to get a test question for.

     * @param string $which one of the names returned by the get_test_questions

     *      method of the relevant qtype_{$qtype}_test_helper class.

     * @return stdClass the requested question object.

     */

    public static function get_question_data($qtype, $which = null) {

        return self::call_question_helper_method('get_{qtype}_question_data_{which}',

            $qtype, $which);

    }

    /**

     * Like {@link make_question()} but returns the data what would be saved from

     * the question editing form instead of the question_definition object.

     *

     * @param string $qtype the question type to get a test question for.

     * @param string $which one of the names returned by the get_test_questions

     *      method of the relevant qtype_{$qtype}_test_helper class.

     * @return stdClass the requested question object.

     */

    public static function get_question_form_data($qtype, $which = null) {

        return self::call_question_helper_method('get_{qtype}_question_form_data_{which}',

            $qtype, $which);

    }

    /**

     * Makes a multichoice question with choices 'A', 'B' and 'C' shuffled. 'A'

     * is correct, defaultmark 1.

     * @return qtype_multichoice_single_question

     */

    public static function make_a_multichoice_single_question() {

        question_bank::load_question_definition_classes('multichoice');

        $mc = new qtype_multichoice_single_question();

        self::initialise_a_question($mc);

        $mc->name = 'Multi-choice question, single response';

        $mc->questiontext = 'The answer is A.';

        $mc->generalfeedback = 'You should have selected A.';

        $mc->qtype = question_bank::get_qtype('multichoice');

        $mc->shuffleanswers = 1;

        $mc->answernumbering = 'abc';

        $mc->showstandardinstruction = 0;

        $mc->answers = array(

            13 => new question_answer(13, 'A', 1, 'A is right', FORMAT_HTML),

            14 => new question_answer(14, 'B', -0.3333333, 'B is wrong', FORMAT_HTML),

            15 => new question_answer(15, 'C', -0.3333333, 'C is wrong', FORMAT_HTML),

        );

        return $mc;

    }

    /**

     * Makes a multichoice question with choices 'A', 'B', 'C' and 'D' shuffled.

     * 'A' and 'C' is correct, defaultmark 1.

     * @return qtype_multichoice_multi_question

     */

    public static function make_a_multichoice_multi_question() {

        question_bank::load_question_definition_classes('multichoice');

        $mc = new qtype_multichoice_multi_question();

        self::initialise_a_question($mc);

        $mc->name = 'Multi-choice question, multiple response';

        $mc->questiontext = 'The answer is A and C.';

        $mc->generalfeedback = 'You should have selected A and C.';

        $mc->qtype = question_bank::get_qtype('multichoice');

        $mc->shuffleanswers = 1;

        $mc->answernumbering = 'abc';

        $mc->showstandardinstruction = 0;

        self::set_standard_combined_feedback_fields($mc);

        $mc->answers = array(

            13 => new question_answer(13, 'A', 0.5, 'A is part of the right answer', FORMAT_HTML),

            14 => new question_answer(14, 'B', -1, 'B is wrong', FORMAT_HTML),

            15 => new question_answer(15, 'C', 0.5, 'C is part of the right answer', FORMAT_HTML),

            16 => new question_answer(16, 'D', -1, 'D is wrong', FORMAT_HTML),

        );

        return $mc;

    }

    /**

     * Makes a matching question to classify 'Dog', 'Frog', 'Toad' and 'Cat' as

     * 'Mammal', 'Amphibian' or 'Insect'.

     * defaultmark 1. Stems are shuffled by default.

     * @return qtype_match_question

     */

    public static function make_a_matching_question() {

        return self::make_question('match');

    }

    /**

     * Makes a truefalse question with correct ansewer true, defaultmark 1.

     * @return qtype_essay_question

     */

    public static function make_an_essay_question() {

        question_bank::load_question_definition_classes('essay');

        $essay = new qtype_essay_question();

        self::initialise_a_question($essay);

        $essay->name = 'Essay question';

        $essay->questiontext = 'Write an essay.';

        $essay->generalfeedback = 'I hope you wrote an interesting essay.';

        $essay->penalty = 0;

        $essay->qtype = question_bank::get_qtype('essay');

        $essay->responseformat = 'editor';

        $essay->responserequired = 1;

        $essay->responsefieldlines = 15;

        $essay->attachments = 0;

        $essay->attachmentsrequired = 0;

        $essay->responsetemplate = '';

        $essay->responsetemplateformat = FORMAT_MOODLE;

        $essay->graderinfo = '';

        $essay->graderinfoformat = FORMAT_MOODLE;

        return $essay;

    }

    /**

     * Add some standard overall feedback to a question. You need to use these

     * specific feedback strings for the corresponding contains_..._feedback

     * methods in {@link qbehaviour_walkthrough_test_base} to works.

     * @param question_definition|stdClass $q the question to add the feedback to.

     */

    public static function set_standard_combined_feedback_fields($q) {

        $q->correctfeedback = self::STANDARD_OVERALL_CORRECT_FEEDBACK;

        $q->correctfeedbackformat = FORMAT_HTML;

        $q->partiallycorrectfeedback = self::STANDARD_OVERALL_PARTIALLYCORRECT_FEEDBACK;

        $q->partiallycorrectfeedbackformat = FORMAT_HTML;

        $q->shownumcorrect = true;

        $q->incorrectfeedback = self::STANDARD_OVERALL_INCORRECT_FEEDBACK;

        $q->incorrectfeedbackformat = FORMAT_HTML;

    }

    /**

     * Add some standard overall feedback to a question's form data.

     */

    public static function set_standard_combined_feedback_form_data($form) {

        $form->correctfeedback = array('text' => self::STANDARD_OVERALL_CORRECT_FEEDBACK,

                                    'format' => FORMAT_HTML);

        $form->partiallycorrectfeedback = array('text' => self::STANDARD_OVERALL_PARTIALLYCORRECT_FEEDBACK,

                                             'format' => FORMAT_HTML);

        $form->shownumcorrect = true;

        $form->incorrectfeedback = array('text' => self::STANDARD_OVERALL_INCORRECT_FEEDBACK,

                                    'format' => FORMAT_HTML);

    }

}

/**

 * Helper for tests that need to simulate records loaded from the database.

 *

 * @copyright  2009 The Open University

 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

 */

abstract class testing_db_record_builder {

    public static function build_db_records(array $table) {

        $columns = array_shift($table);

        $records = array();

        foreach ($table as $row) {

            if (count($row) != count($columns)) {

                throw new coding_exception("Row contains the wrong number of fields.");

            }

            $rec = new stdClass();

            foreach ($columns as $i => $name) {

                $rec->$name = $row[$i];

            }

            $records[] = $rec;

        }

        return $records;

    }

}

/**

 * Helper base class for tests that need to simulate records loaded from the

 * database.

 *

 * @copyright  2009 The Open University

 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

 */

abstract class data_loading_method_test_base extends advanced_testcase {

    public function build_db_records(array $table) {

        return testing_db_record_builder::build_db_records($table);

    }

}

abstract class question_testcase extends advanced_testcase {

    /**

     * Tolerance accepted in some unit tests when float operations are involved.

     */

    const GRADE_DELTA = 0.00000005;

    public function assert($expectation, $compare, $notused = '') {

        if (get_class($expectation) === 'question_pattern_expectation') {

            $this->assertMatchesRegularExpression($expectation->pattern, $compare,

                    'Expected regex ' . $expectation->pattern . ' not found in ' . $compare);

            return;

        } else if (get_class($expectation) === 'question_no_pattern_expectation') {

            $this->assertDoesNotMatchRegularExpression($expectation->pattern, $compare,

                    'Unexpected regex ' . $expectation->pattern . ' found in ' . $compare);

            return;

        } else if (get_class($expectation) === 'question_contains_tag_with_attributes') {

            $this->assertTag(array('tag'=>$expectation->tag, 'attributes'=>$expectation->expectedvalues), $compare,

                    'Looking for a ' . $expectation->tag . ' with attributes ' . html_writer::attributes($expectation->expectedvalues) . ' in ' . $compare);

            foreach ($expectation->forbiddenvalues as $k=>$v) {

                $attr = $expectation->expectedvalues;

                $attr[$k] = $v;

                $this->assertNotTag(array('tag'=>$expectation->tag, 'attributes'=>$attr), $compare,

                        $expectation->tag . ' had a ' . $k . ' attribute that should not be there in ' . $compare);

            }

            return;

        } else if (get_class($expectation) === 'question_contains_tag_with_attribute') {

            $attr = array($expectation->attribute=>$expectation->value);

            $this->assertTag(array('tag'=>$expectation->tag, 'attributes'=>$attr), $compare,

                    'Looking for a ' . $expectation->tag . ' with attribute ' . html_writer::attributes($attr) . ' in ' . $compare);

            return;

        } else if (get_class($expectation) === 'question_does_not_contain_tag_with_attributes') {

            $this->assertNotTag(array('tag'=>$expectation->tag, 'attributes'=>$expectation->attributes), $compare,

                    'Unexpected ' . $expectation->tag . ' with attributes ' . html_writer::attributes($expectation->attributes) . ' found in ' . $compare);

            return;

        } else if (get_class($expectation) === 'question_contains_select_expectation') {

            $tag = array('tag'=>'select', 'attributes'=>array('name'=>$expectation->name),

                'children'=>array('count'=>count($expectation->choices)));

            if ($expectation->enabled === false) {

                $tag['attributes']['disabled'] = 'disabled';

            } else if ($expectation->enabled === true) {

                // TODO

            }

            foreach(array_keys($expectation->choices) as $value) {

                if ($expectation->selected === $value) {

                    $tag['child'] = array('tag'=>'option', 'attributes'=>array('value'=>$value, 'selected'=>'selected'));

                } else {

                    $tag['child'] = array('tag'=>'option', 'attributes'=>array('value'=>$value));

                }

            }

            $this->assertTag($tag, $compare, 'expected select not found in ' . $compare);

            return;

        } else if (get_class($expectation) === 'question_check_specified_fields_expectation') {

            $expect = (array)$expectation->expect;

            $compare = (array)$compare;

            foreach ($expect as $k=>$v) {

                if (!array_key_exists($k, $compare)) {

                    $this->fail("Property {$k} does not exist");

                }

                if ($v != $compare[$k]) {

                    $this->fail("Property {$k} is different");

                }

            }

            $this->assertTrue(true);

            return;

        } else if (get_class($expectation) === 'question_contains_tag_with_contents') {

            $this->assertTag(array('tag'=>$expectation->tag, 'content'=>$expectation->content), $compare,

                    'Looking for a ' . $expectation->tag . ' with content ' . $expectation->content . ' in ' . $compare);

            return;

        }

        throw new coding_exception('Unknown expectiontion:'.get_class($expectation));

    }

    /**

     * Use this function rather than assert when checking the value of options within a select element.

     *

     * @param question_contains_select_expectation $expectation The select expectation class

     * @param string $html The rendered output to check against

     */

    public function assert_select_options($expectation, $html) {

        if (get_class($expectation) !== 'question_contains_select_expectation') {

            throw new coding_exception('Unsuitable expectiontion: '.get_class($expectation));

        }

        $dom = new DOMDocument();

        $dom->loadHTML($html);

        $selects = $dom->getElementsByTagName('select');

        foreach ($selects as $select) {

            if ($select->getAttribute('name') == $expectation->name) {

                $options = $select->getElementsByTagName('option');

                foreach ($options as $key => $option) {

                    if ($key == 0) {

                        // Check the value of the first option. This is often 'Choose...' or a nbsp.

                        // Note it is necessary to pass a nbsp character in the test here and not just ' '.

                        // Many tests do not require checking of this option.

                        if (isset($expectation->choices[$option->getAttribute('value')])) {

                            $this->assertEquals($expectation->choices[$option->getAttribute('value')], $option->textContent);

                        }

                        continue;

                    }

                    // Check the value of the options in the select.

                    $this->assertEquals($expectation->choices[$option->getAttribute('value')], $option->textContent);

                    if ($expectation->selected && $option->getAttribute('value') == $expectation->selected) {

                        // Check the right option is selected.

                        $this->assertTrue(!empty($option->getAttribute('selected')));

                    }

                }

                if ($expectation->enabled) {

                    // Check the select element is enabled.

                    $this->assertTrue(!$select->getAttribute('disabled'));

                }

            }

        }

        return;

    }

    /**

     * Check that 2 XML strings are the same, ignoring differences in line endings.

     *

     * @param string $expectedxml The expected XML string

     * @param string $xml The XML string to check

     */

    public function assert_same_xml($expectedxml, $xml) {

        $this->assertEquals(

            phpunit_util::normalise_line_endings($expectedxml),

            phpunit_util::normalise_line_endings($xml)

        );

    }

}

class question_contains_tag_with_contents {

    public $tag;

    public $content;

    public $message;

    public function __construct($tag, $content, $message = '') {

        $this->tag = $tag;

        $this->content = $content;

        $this->message = $message;

    }

}

class question_check_specified_fields_expectation {

    public $expect;

    public $message;

    function __construct($expected, $message = '') {

        $this->expect = $expected;

        $this->message = $message;

    }

}

class question_contains_select_expectation {

    public $name;

    public $choices;

    public $selected;

    public $enabled;

    public $message;

    public function __construct($name, $choices, $selected = null, $enabled = null, $message = '') {

        $this->name = $name;

        $this->choices = $choices;

        $this->selected = $selected;

        $this->enabled = $enabled;

        $this->message = $message;

    }

}

class question_does_not_contain_tag_with_attributes {

    public $tag;

    public $attributes;

    public $message;

    public function __construct($tag, $attributes, $message = '') {

        $this->tag = $tag;

        $this->attributes = $attributes;

        $this->message = $message;

    }

}

class question_contains_tag_with_attribute {

    public $tag;

    public $attribute;

    public $value;

    public $message;

    public function __construct($tag, $attribute, $value, $message = '') {

        $this->tag = $tag;

        $this->attribute = $attribute;

        $this->value = $value;

        $this->message = $message;

    }

}

class question_contains_tag_with_attributes {

    public $tag;

    public $expectedvalues = array();

    public $forbiddenvalues = array();

    public $message;

    public function __construct($tag, $expectedvalues, $forbiddenvalues=array(), $message = '') {

        $this->tag = $tag;

        $this->expectedvalues = $expectedvalues;

        $this->forbiddenvalues = $forbiddenvalues;

        $this->message = $message;

    }

}

class question_pattern_expectation {

    public $pattern;

    public $message;

    public function __construct($pattern, $message = '') {

        $this->pattern = $pattern;

        $this->message = $message;

    }

}

class question_no_pattern_expectation {

    public $pattern;

    public $message;

    public function __construct($pattern, $message = '') {

        $this->pattern = $pattern;

        $this->message = $message;

    }

}

/**

 * Helper base class for question walk-through tests.

 *

 * The purpose of tests that use this base class is to simulate the entire

 * interaction of a student making an attempt at a question. Therefore,

 * these are not really unit tests. They would more accurately be described

 * as integration tests. However, whether they are unit tests or not,

 * it works well to implement them in PHPUnit.

 *

 * Historically, tests like this were made because Moodle did not have anything

 * like Behat for end-to-end testing. Even though we do now have Behat, it makes

 * sense to keep these walk-through tests. They run massively faster than Behat

 * tests, which gives you a much faster feedback loop while doing development.

 * They also make it quite easy to test things like regrading the attempt after

 * the question has been edited, which would be possible but very fiddly in Behat.

 *

 * Ideally, the full set of tests for the question class of a question type would be:

 *

 * 1. A lot of unit tests for each qtype_myqtype_question class method

 *    like grade_response, is_complete_response, is_same_response, ...

 *

 * 2. Several of these walk-through tests, to test the end-to-end interaction

 *    of a student with a question, for example with different behaviours.

 *

 * 3. Just one Behat test, using question preview, to verify that everything

 *    is plugged together correctly and works when used through the UI.

 *

 * What one would expect to see in one of these walk-through tests is:

 *

 * // 1. Set up a question: $q.

 *

 * // 2. A call to $this->start_attempt_at_question($q, ...); with the relevant options.

 *

 * // 3. Some number of calls to $this->process_submission passing an array of simulated

 * //    POST data that matches what would be sent back be submitting a form that contains

 * //    the form fields that are output by rendering the question. This is like clicking

 * //    the 'Check' button in a question, or navigating to the next page in a quiz.

 *

 * // 4. A call to $this->finish(); which is the equivalent of clicking

 * //    'Submit all and finish' in the quiz.

 *

 * // 5. After each of steps 2-4 above, one would expect to see a certain amount of

 * //    validation of the state of the question and how the question is rendered,

 * //    using methods like $this->check_current_state(), $this->check_current_output, etc.

 *

 * The best way to work out how to write tests like this is probably to look at

 * some examples in other question types or question behaviours.

 *

 * In writing these tests, it is worth noting the following points:

 *

 * a) The easiest mistake to make is at step 3. You need to ensure that your

 *    simulated post data actually matches what gets sent back when the

 *    question is submitted in the browser. Try checking it against the

 *    HTTP POST requests you see in your browser when the question is submitted.

 *    Some question types have a $q->prepare_simulated_post_data() method that

 *    can help with this.

 *

 * b) In the past, tests like these used to contain even more repetitive code,

 *    and so they were re-factored to add the helper methods like

 *    start_attempt_at_question, process_submission, finish. That change had

 *    good effects, like reducing duplicate code. However, there were down-sides.

 *    The extra layers of indirection hide what is going on, which means these

 *    tests are harder to understand until you know what the helpers are doing.

 *    If you want an interesting exercise, take one of the walk-through tests,

 *    and inline all the helpers. This might be a good way to understand more about

 *    the question engine API. However, having made the everything-inlined code

 *    and learned from the process, you should then just throw it away.

 *

 * c) The way check_current_output works is weird. When these tests were first written

 *    Moodle used SimpleTest for unit tests and check_current_output os written in a

 *    style that made sense there. When we moved to PHPUnit, a quick and dirty

 *    conversion was done. That was a pragmatic move at the time, and we just have

 *    to live with the result. Sorry. (And: don't copy that style for new things.)

 *

 * @copyright  2009 The Open University

 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

 */

abstract class qbehaviour_walkthrough_test_base extends question_testcase {

    /** @var question_display_options */

    protected $displayoptions;

    /** @var question_usage_by_activity */

    protected $quba;

    /** @var int The slot number of the question_attempt we are using in $quba. */

    protected $slot;

    /**

     * @var string after {@link render()} has been called, this contains the

     * display of the question in its current state.

     */

    protected $currentoutput = '';

    protected function setUp(): void {

        parent::setUp();

        $this->resetAfterTest();

        $this->setAdminUser();

        $this->displayoptions = new question_display_options();

        $this->quba = question_engine::make_questions_usage_by_activity('unit_test',

            context_system::instance());

    }

    protected function tearDown(): void {

        $this->displayoptions = null;

        $this->quba = null;

        parent::tearDown();

    }

    protected function start_attempt_at_question($question, $preferredbehaviour,

                                                 $maxmark = null, $variant = 1) {

        $this->quba->set_preferred_behaviour($preferredbehaviour);

        $this->slot = $this->quba->add_question($question, $maxmark);

        $this->quba->start_question($this->slot, $variant);

    }

    /**

     * Convert an array of data destined for one question to the equivalent POST data.

     * @param array $data the data for the quetsion.

     * @return array the complete post data.

     */

    protected function response_data_to_post($data) {

        $prefix = $this->quba->get_field_prefix($this->slot);

        $fulldata = array(

            'slots' => $this->slot,

            $prefix . ':sequencecheck' => $this->get_question_attempt()->get_sequence_check_count(),

        );

        foreach ($data as $name => $value) {

            $fulldata[$prefix . $name] = $value;

        }

        return $fulldata;

    }

    protected function process_submission($data) {

        // Backwards compatibility.

        reset($data);

        if (count($data) == 1 && key($data) === '-finish') {

            $this->finish();

        }

        $this->quba->process_all_actions(time(), $this->response_data_to_post($data));

    }

    protected function process_autosave($data) {

        $this->quba->process_all_autosaves(null, $this->response_data_to_post($data));

    }

    protected function finish() {

        $this->quba->finish_all_questions();

    }

    protected function manual_grade($comment, $mark, $commentformat = null) {

        $this->quba->manual_grade($this->slot, $comment, $mark, $commentformat);

    }

    protected function save_quba(moodle_database $db = null) {

        question_engine::save_questions_usage_by_activity($this->quba, $db);

    }

    protected function load_quba(moodle_database $db = null) {

        $this->quba = question_engine::load_questions_usage_by_activity($this->quba->get_id(), $db);

    }

    protected function delete_quba() {

        question_engine::delete_questions_usage_by_activity($this->quba->get_id());

        $this->quba = null;

    }

    /**

     * Asserts if the manual comment for the question is equal to the provided arguments.

     * @param $comment Comment text

     * @param $commentformat Comment format

     */

    protected function check_comment($comment, $commentformat) {

        $actualcomment = $this->quba->get_question_attempt($this->slot)->get_manual_comment();

        $this->assertEquals(

                [$comment, $commentformat],

                [$actualcomment[0], $actualcomment[1]]

        );

    }

    protected function check_current_state($state) {

        $this->assertEquals($state, $this->quba->get_question_state($this->slot),

            'Questions is in the wrong state.');

    }

    protected function check_current_mark($mark) {

        if (is_null($mark)) {

            $this->assertNull($this->quba->get_question_mark($this->slot));

        } else {

            if ($mark == 0) {

                // PHP will think a null mark and a mark of 0 are equal,

                // so explicity check not null in this case.

                $this->assertNotNull($this->quba->get_question_mark($this->slot));

            }

            $this->assertEqualsWithDelta($mark, $this->quba->get_question_mark($this->slot),

                 0.000001, 'Expected mark and actual mark differ.');

        }

    }

    /**

     * Generate the HTML rendering of the question in its current state in

     * $this->currentoutput so that it can be verified.

     */

    protected function render() {

        $this->quba->preload_all_step_users();

        $this->currentoutput = $this->quba->render_question($this->slot, $this->displayoptions);

    }

    protected function check_output_contains_text_input($name, $value = null, $enabled = true) {

        $attributes = array(

            'type' => 'text',

            'name' => $this->quba->get_field_prefix($this->slot) . $name,

        );

        if (!is_null($value)) {

            $attributes['value'] = $value;

        }

        if (!$enabled) {

            $attributes['readonly'] = 'readonly';

        }

        $matcher = $this->get_tag_matcher('input', $attributes);

        $this->assertTag($matcher, $this->currentoutput,

                'Looking for an input with attributes ' . html_writer::attributes($attributes) . ' in ' . $this->currentoutput);

        if ($enabled) {

            $matcher['attributes']['readonly'] = 'readonly';

            $this->assertNotTag($matcher, $this->currentoutput,

                    'input with attributes ' . html_writer::attributes($attributes) .

                    ' should not be read-only in ' . $this->currentoutput);

        }

    }

    protected function check_output_contains_text_input_with_class($name, $class = null) {

        $attributes = array(

            'type' => 'text',

            'name' => $this->quba->get_field_prefix($this->slot) . $name,

        );

        if (!is_null($class)) {

            $attributes['class'] = 'regexp:/\b' . $class . '\b/';

        }

        $matcher = $this->get_tag_matcher('input', $attributes);

        $this->assertTag($matcher, $this->currentoutput,

                'Looking for an input with attributes ' . html_writer::attributes($attributes) . ' in ' . $this->currentoutput);

    }

    protected function check_output_does_not_contain_text_input_with_class($name, $class = null) {

        $attributes = array(

            'type' => 'text',

            'name' => $this->quba->get_field_prefix($this->slot) . $name,

        );

        if (!is_null($class)) {

            $attributes['class'] = 'regexp:/\b' . $class . '\b/';

        }

        $matcher = $this->get_tag_matcher('input', $attributes);

        $this->assertNotTag($matcher, $this->currentoutput,

                'Unexpected input with attributes ' . html_writer::attributes($attributes) . ' found in ' . $this->currentoutput);

    }

    protected function check_output_contains_hidden_input($name, $value) {

        $attributes = array(

            'type' => 'hidden',

            'name' => $this->quba->get_field_prefix($this->slot) . $name,

            'value' => $value,

        );

        $this->assertTag($this->get_tag_matcher('input', $attributes), $this->currentoutput,

                'Looking for a hidden input with attributes ' . html_writer::attributes($attributes) . ' in ' . $this->currentoutput);

    }

    protected function check_output_contains($string) {

        $this->render();

        $this->assertStringContainsString($string, $this->currentoutput,

                'Expected string ' . $string . ' not found in ' . $this->currentoutput);

    }

    protected function check_output_does_not_contain($string) {