<?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/>.

/**
 * Unit tests for the lib/upgradelib.php library.
 *
 * @package   core
 * @category  phpunit
 * @copyright 2013 onwards Eloy Lafuente (stronk7) {@link http://stronk7.com}
 * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */

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

global $CFG;
require_once($CFG->libdir.'/upgradelib.php');


/**
 * Tests various classes and functions in upgradelib.php library.
 */
class core_upgradelib_testcase extends advanced_testcase {

    /**
     * Test the {@link upgrade_stale_php_files_present() function
     */
    public function test_upgrade_stale_php_files_present() {
        // Just call the function, must return bool false always
        // if there aren't any old files in the codebase.
        $this->assertFalse(upgrade_stale_php_files_present());
    }

    /**
     * Populate some fake grade items into the database with specified
     * sortorder and course id.
     *
     * NOTE: This function doesn't make much attempt to respect the
     * gradebook internals, its simply used to fake some data for
     * testing the upgradelib function. Please don't use it for other
     * purposes.
     *
     * @param int $courseid id of course
     * @param int $sortorder numeric sorting order of item
     * @return stdClass grade item object from the database.
     */
    private function insert_fake_grade_item_sortorder($courseid, $sortorder) {
        global $DB, $CFG;
        require_once($CFG->libdir.'/gradelib.php');

        $item = new stdClass();
        $item->courseid = $courseid;
        $item->sortorder = $sortorder;
        $item->gradetype = GRADE_TYPE_VALUE;
        $item->grademin = 30;
        $item->grademax = 110;
        $item->itemnumber = 1;
        $item->iteminfo = '';
        $item->timecreated = time();
        $item->timemodified = time();

        $item->id = $DB->insert_record('grade_items', $item);

        return $DB->get_record('grade_items', array('id' => $item->id));
    }

    public function test_upgrade_fix_missing_root_folders_draft() {
        global $DB, $SITE;

        $this->resetAfterTest(true);

        $user = $this->getDataGenerator()->create_user();
        $usercontext = context_user::instance($user->id);
        $this->setUser($user);
        $resource1 = $this->getDataGenerator()->get_plugin_generator('mod_resource')
            ->create_instance(array('course' => $SITE->id));
        $context = context_module::instance($resource1->cmid);
        $draftitemid = 0;
        file_prepare_draft_area($draftitemid, $context->id, 'mod_resource', 'content', 0);

        $queryparams = array(
            'component' => 'user',
            'contextid' => $usercontext->id,
            'filearea' => 'draft',
            'itemid' => $draftitemid,
        );

        // Make sure there are two records in files for the draft file area and one of them has filename '.'.
        $records = $DB->get_records_menu('files', $queryparams, '', 'id, filename');
        $this->assertEquals(2, count($records));
        $this->assertTrue(in_array('.', $records));
        $originalhash = $DB->get_field('files', 'pathnamehash', $queryparams + array('filename' => '.'));

        // Delete record with filename '.' and make sure it does not exist any more.
        $DB->delete_records('files', $queryparams + array('filename' => '.'));

        $records = $DB->get_records_menu('files', $queryparams, '', 'id, filename');
        $this->assertEquals(1, count($records));
        $this->assertFalse(in_array('.', $records));

        // Run upgrade script and make sure the record is restored.
        upgrade_fix_missing_root_folders_draft();

        $records = $DB->get_records_menu('files', $queryparams, '', 'id, filename');
        $this->assertEquals(2, count($records));
        $this->assertTrue(in_array('.', $records));
        $newhash = $DB->get_field('files', 'pathnamehash', $queryparams + array('filename' => '.'));
        $this->assertEquals($originalhash, $newhash);
    }

    /**
     * Test upgrade minmaxgrade step.
     */
    public function test_upgrade_minmaxgrade() {
        global $CFG, $DB;
        require_once($CFG->libdir . '/gradelib.php');
        $initialminmax = $CFG->grade_minmaxtouse;
        $this->resetAfterTest();

        $c1 = $this->getDataGenerator()->create_course();
        $c2 = $this->getDataGenerator()->create_course();
        $c3 = $this->getDataGenerator()->create_course();
        $u1 = $this->getDataGenerator()->create_user();
        $a1 = $this->getDataGenerator()->create_module('assign', array('course' => $c1, 'grade' => 100));
        $a2 = $this->getDataGenerator()->create_module('assign', array('course' => $c2, 'grade' => 100));
        $a3 = $this->getDataGenerator()->create_module('assign', array('course' => $c3, 'grade' => 100));

        $cm1 = get_coursemodule_from_instance('assign', $a1->id);
        $ctx1 = context_module::instance($cm1->id);
        $assign1 = new assign($ctx1, $cm1, $c1);

        $cm2 = get_coursemodule_from_instance('assign', $a2->id);
        $ctx2 = context_module::instance($cm2->id);
        $assign2 = new assign($ctx2, $cm2, $c2);

        $cm3 = get_coursemodule_from_instance('assign', $a3->id);
        $ctx3 = context_module::instance($cm3->id);
        $assign3 = new assign($ctx3, $cm3, $c3);

        // Give a grade to the student.
        $ug = $assign1->get_user_grade($u1->id, true);
        $ug->grade = 10;
        $assign1->update_grade($ug);

        $ug = $assign2->get_user_grade($u1->id, true);
        $ug->grade = 20;
        $assign2->update_grade($ug);

        $ug = $assign3->get_user_grade($u1->id, true);
        $ug->grade = 30;
        $assign3->update_grade($ug);


        // Run the upgrade.
        upgrade_minmaxgrade();

        // Nothing has happened.
        $this->assertFalse($DB->record_exists('config', array('name' => 'show_min_max_grades_changed_' . $c1->id)));
        $this->assertSame(false, grade_get_setting($c1->id, 'minmaxtouse', false, true));
        $this->assertFalse($DB->record_exists('grade_items', array('needsupdate' => 1, 'courseid' => $c1->id)));
        $this->assertFalse($DB->record_exists('config', array('name' => 'show_min_max_grades_changed_' . $c2->id)));
        $this->assertSame(false, grade_get_setting($c2->id, 'minmaxtouse', false, true));
        $this->assertFalse($DB->record_exists('grade_items', array('needsupdate' => 1, 'courseid' => $c2->id)));
        $this->assertFalse($DB->record_exists('config', array('name' => 'show_min_max_grades_changed_' . $c3->id)));
        $this->assertSame(false, grade_get_setting($c3->id, 'minmaxtouse', false, true));
        $this->assertFalse($DB->record_exists('grade_items', array('needsupdate' => 1, 'courseid' => $c3->id)));

        // Create inconsistency in c1 and c2.
        $giparams = array('itemtype' => 'mod', 'itemmodule' => 'assign', 'iteminstance' => $a1->id,
                'courseid' => $c1->id, 'itemnumber' => 0);
        $gi = grade_item::fetch($giparams);
        $gi->grademin = 5;
        $gi->update();

        $giparams = array('itemtype' => 'mod', 'itemmodule' => 'assign', 'iteminstance' => $a2->id,
                'courseid' => $c2->id, 'itemnumber' => 0);
        $gi = grade_item::fetch($giparams);
        $gi->grademax = 50;
        $gi->update();


        // C1 and C2 should be updated, but the course setting should not be set.
        $CFG->grade_minmaxtouse = GRADE_MIN_MAX_FROM_GRADE_GRADE;

        // Run the upgrade.
        upgrade_minmaxgrade();

        // C1 and C2 were partially updated.
        $this->assertTrue($DB->record_exists('config', array('name' => 'show_min_max_grades_changed_' . $c1->id)));
        $this->assertSame(false, grade_get_setting($c1->id, 'minmaxtouse', false, true));
        $this->assertTrue($DB->record_exists('grade_items', array('needsupdate' => 1, 'courseid' => $c1->id)));
        $this->assertTrue($DB->record_exists('config', array('name' => 'show_min_max_grades_changed_' . $c2->id)));
        $this->assertSame(false, grade_get_setting($c2->id, 'minmaxtouse', false, true));
        $this->assertTrue($DB->record_exists('grade_items', array('needsupdate' => 1, 'courseid' => $c2->id)));

        // Nothing has happened for C3.
        $this->assertFalse($DB->record_exists('config', array('name' => 'show_min_max_grades_changed_' . $c3->id)));
        $this->assertSame(false, grade_get_setting($c3->id, 'minmaxtouse', false, true));
        $this->assertFalse($DB->record_exists('grade_items', array('needsupdate' => 1, 'courseid' => $c3->id)));


        // Course setting should not be set on a course that has the setting already.
        $CFG->grade_minmaxtouse = GRADE_MIN_MAX_FROM_GRADE_ITEM;
        grade_set_setting($c1->id, 'minmaxtouse', -1); // Sets different value than constant to check that it remained the same.

        // Run the upgrade.
        upgrade_minmaxgrade();

        // C2 was updated.
        $this->assertSame((string) GRADE_MIN_MAX_FROM_GRADE_GRADE, grade_get_setting($c2->id, 'minmaxtouse', false, true));

        // Nothing has happened for C1.
        $this->assertSame('-1', grade_get_setting($c1->id, 'minmaxtouse', false, true));

        // Nothing has happened for C3.
        $this->assertFalse($DB->record_exists('config', array('name' => 'show_min_max_grades_changed_' . $c3->id)));
        $this->assertSame(false, grade_get_setting($c3->id, 'minmaxtouse', false, true));
        $this->assertFalse($DB->record_exists('grade_items', array('needsupdate' => 1, 'courseid' => $c3->id)));


        // Final check, this time we'll unset the default config.
        unset($CFG->grade_minmaxtouse);
        grade_set_setting($c1->id, 'minmaxtouse', null);

        // Run the upgrade.
        upgrade_minmaxgrade();

        // C1 was updated.
        $this->assertSame((string) GRADE_MIN_MAX_FROM_GRADE_GRADE, grade_get_setting($c1->id, 'minmaxtouse', false, true));

        // Nothing has happened for C3.
        $this->assertFalse($DB->record_exists('config', array('name' => 'show_min_max_grades_changed_' . $c3->id)));
        $this->assertSame(false, grade_get_setting($c3->id, 'minmaxtouse', false, true));
        $this->assertFalse($DB->record_exists('grade_items', array('needsupdate' => 1, 'courseid' => $c3->id)));

        // Restore value.
        $CFG->grade_minmaxtouse = $initialminmax;
    }

    public function test_upgrade_extra_credit_weightoverride() {
        global $DB, $CFG;

        $this->resetAfterTest(true);

        require_once($CFG->libdir . '/db/upgradelib.php');

        $c = array();
        $a = array();
        $gi = array();
        for ($i=0; $i<5; $i++) {
            $c[$i] = $this->getDataGenerator()->create_course();
            $a[$i] = array();
            $gi[$i] = array();
            for ($j=0;$j<3;$j++) {
                $a[$i][$j] = $this->getDataGenerator()->create_module('assign', array('course' => $c[$i], 'grade' => 100));
                $giparams = array('itemtype' => 'mod', 'itemmodule' => 'assign', 'iteminstance' => $a[$i][$j]->id,
                    'courseid' => $c[$i]->id, 'itemnumber' => 0);
                $gi[$i][$j] = grade_item::fetch($giparams);
            }
        }

        // Case 1: Course $c[0] has aggregation method different from natural.
        $coursecategory = grade_category::fetch_course_category($c[0]->id);
        $coursecategory->aggregation = GRADE_AGGREGATE_WEIGHTED_MEAN;
        $coursecategory->update();
        $gi[0][1]->aggregationcoef = 1;
        $gi[0][1]->update();
        $gi[0][2]->weightoverride = 1;
        $gi[0][2]->update();

        // Case 2: Course $c[1] has neither extra credits nor overrides

        // Case 3: Course $c[2] has extra credits but no overrides
        $gi[2][1]->aggregationcoef = 1;
        $gi[2][1]->update();

        // Case 4: Course $c[3] has no extra credits and has overrides
        $gi[3][2]->weightoverride = 1;
        $gi[3][2]->update();

        // Case 5: Course $c[4] has both extra credits and overrides
        $gi[4][1]->aggregationcoef = 1;
        $gi[4][1]->update();
        $gi[4][2]->weightoverride = 1;
        $gi[4][2]->update();

        // Run the upgrade script and make sure only course $c[4] was marked as needed to be fixed.
        upgrade_extra_credit_weightoverride();

        $this->assertTrue(empty($CFG->{'gradebook_calculations_freeze_' . $c[0]->id}));
        $this->assertTrue(empty($CFG->{'gradebook_calculations_freeze_' . $c[1]->id}));
        $this->assertTrue(empty($CFG->{'gradebook_calculations_freeze_' . $c[2]->id}));
        $this->assertTrue(empty($CFG->{'gradebook_calculations_freeze_' . $c[3]->id}));
        $this->assertEquals(20150619, $CFG->{'gradebook_calculations_freeze_' . $c[4]->id});

        set_config('gradebook_calculations_freeze_' . $c[4]->id, null);

        // Run the upgrade script for a single course only.
        upgrade_extra_credit_weightoverride($c[0]->id);
        $this->assertTrue(empty($CFG->{'gradebook_calculations_freeze_' . $c[0]->id}));
        upgrade_extra_credit_weightoverride($c[4]->id);
        $this->assertEquals(20150619, $CFG->{'gradebook_calculations_freeze_' . $c[4]->id});
    }

    /**
     * Test the upgrade function for flagging courses with calculated grade item problems.
     */
    public function test_upgrade_calculated_grade_items_freeze() {
        global $DB, $CFG;

        $this->resetAfterTest();

        require_once($CFG->libdir . '/db/upgradelib.php');

        // Create a user.
        $user = $this->getDataGenerator()->create_user();

        // Create a couple of courses.
        $course1 = $this->getDataGenerator()->create_course();
        $course2 = $this->getDataGenerator()->create_course();
        $course3 = $this->getDataGenerator()->create_course();

        // Enrol the user in the courses.
        $studentrole = $DB->get_record('role', array('shortname' => 'student'));
        $maninstance1 = $DB->get_record('enrol', array('courseid' => $course1->id, 'enrol' => 'manual'), '*', MUST_EXIST);
        $maninstance2 = $DB->get_record('enrol', array('courseid' => $course2->id, 'enrol' => 'manual'), '*', MUST_EXIST);
        $maninstance3 = $DB->get_record('enrol', array('courseid' => $course3->id, 'enrol' => 'manual'), '*', MUST_EXIST);
        $manual = enrol_get_plugin('manual');
        $manual->enrol_user($maninstance1, $user->id, $studentrole->id);
        $manual->enrol_user($maninstance2, $user->id, $studentrole->id);
        $manual->enrol_user($maninstance3, $user->id, $studentrole->id);

        // To create the data we need we freeze the grade book to use the old behaviour.
        set_config('gradebook_calculations_freeze_' . $course1->id, 20150627);
        set_config('gradebook_calculations_freeze_' . $course2->id, 20150627);
        set_config('gradebook_calculations_freeze_' . $course3->id, 20150627);
        $CFG->grade_minmaxtouse = 2;

        // Creating a category for a grade item.
        $gradecategory = new grade_category();
        $gradecategory->fullname = 'calculated grade category';
        $gradecategory->courseid = $course1->id;
        $gradecategory->insert();
        $gradecategoryid = $gradecategory->id;

        // This is a manual grade item.
        $gradeitem = new grade_item();
        $gradeitem->itemname = 'grade item one';
        $gradeitem->itemtype = 'manual';
        $gradeitem->categoryid = $gradecategoryid;
        $gradeitem->courseid = $course1->id;
        $gradeitem->idnumber = 'gi1';
        $gradeitem->insert();

        // Changing the category into a calculated grade category.
        $gradecategoryitem = grade_item::fetch(array('iteminstance' => $gradecategory->id));
        $gradecategoryitem->calculation = '=##gi' . $gradeitem->id . '##/2';
        $gradecategoryitem->update();

        // Setting a grade for the student.
        $grade = $gradeitem->get_grade($user->id, true);
        $grade->finalgrade = 50;
        $grade->update();
        // Creating all the grade_grade items.
        grade_regrade_final_grades($course1->id);
        // Updating the grade category to a new grade max and min.
        $gradecategoryitem->grademax = 50;
        $gradecategoryitem->grademin = 5;
        $gradecategoryitem->update();

        // Different manual grade item for course 2. We are creating a course with a calculated grade item that has a grade max of
        // 50. The grade_grade will have a rawgrademax of 100 regardless.
        $gradeitem = new grade_item();
        $gradeitem->itemname = 'grade item one';
        $gradeitem->itemtype = 'manual';
        $gradeitem->courseid = $course2->id;
        $gradeitem->idnumber = 'gi1';
        $gradeitem->grademax = 25;
        $gradeitem->insert();

        // Calculated grade item for course 2.
        $calculatedgradeitem = new grade_item();
        $calculatedgradeitem->itemname = 'calculated grade';
        $calculatedgradeitem->itemtype = 'manual';
        $calculatedgradeitem->courseid = $course2->id;
        $calculatedgradeitem->calculation = '=##gi' . $gradeitem->id . '##*2';
        $calculatedgradeitem->grademax = 50;
        $calculatedgradeitem->insert();

        // Assigning a grade for the user.
        $grade = $gradeitem->get_grade($user->id, true);
        $grade->finalgrade = 10;
        $grade->update();

        // Setting all of the grade_grade items.
        grade_regrade_final_grades($course2->id);

        // Different manual grade item for course 3. We are creating a course with a calculated grade item that has a grade max of
        // 50. The grade_grade will have a rawgrademax of 100 regardless.
        $gradeitem = new grade_item();
        $gradeitem->itemname = 'grade item one';
        $gradeitem->itemtype = 'manual';
        $gradeitem->courseid = $course3->id;
        $gradeitem->idnumber = 'gi1';
        $gradeitem->grademax = 25;
        $gradeitem->insert();

        // Calculated grade item for course 2.
        $calculatedgradeitem = new grade_item();
        $calculatedgradeitem->itemname = 'calculated grade';
        $calculatedgradeitem->itemtype = 'manual';
        $calculatedgradeitem->courseid = $course3->id;
        $calculatedgradeitem->calculation = '=##gi' . $gradeitem->id . '##*2';
        $calculatedgradeitem->grademax = 50;
        $calculatedgradeitem->insert();

        // Assigning a grade for the user.
        $grade = $gradeitem->get_grade($user->id, true);
        $grade->finalgrade = 10;
        $grade->update();

        // Setting all of the grade_grade items.
        grade_regrade_final_grades($course3->id);
        // Need to do this first before changing the other courses, otherwise they will be flagged too early.
        set_config('gradebook_calculations_freeze_' . $course3->id, null);
        upgrade_calculated_grade_items($course3->id);
        $this->assertEquals(20150627, $CFG->{'gradebook_calculations_freeze_' . $course3->id});

        // Change the setting back to null.
        set_config('gradebook_calculations_freeze_' . $course1->id, null);
        set_config('gradebook_calculations_freeze_' . $course2->id, null);
        // Run the upgrade.
        upgrade_calculated_grade_items();
        // The setting should be set again after the upgrade.
        $this->assertEquals(20150627, $CFG->{'gradebook_calculations_freeze_' . $course1->id});
        $this->assertEquals(20150627, $CFG->{'gradebook_calculations_freeze_' . $course2->id});
    }

    function test_upgrade_calculated_grade_items_regrade() {
        global $DB, $CFG;

        $this->resetAfterTest();

        require_once($CFG->libdir . '/db/upgradelib.php');

        // Create a user.
        $user = $this->getDataGenerator()->create_user();

        // Create a course.
        $course = $this->getDataGenerator()->create_course();

        // Enrol the user in the course.
        $studentrole = $DB->get_record('role', array('shortname' => 'student'));
        $maninstance1 = $DB->get_record('enrol', array('courseid' => $course->id, 'enrol' => 'manual'), '*', MUST_EXIST);
        $manual = enrol_get_plugin('manual');
        $manual->enrol_user($maninstance1, $user->id, $studentrole->id);

        set_config('upgrade_calculatedgradeitemsonlyregrade', 1);

        // Creating a category for a grade item.
        $gradecategory = new grade_category();
        $gradecategory->fullname = 'calculated grade category';
        $gradecategory->courseid = $course->id;
        $gradecategory->insert();
        $gradecategoryid = $gradecategory->id;

        // This is a manual grade item.
        $gradeitem = new grade_item();
        $gradeitem->itemname = 'grade item one';
        $gradeitem->itemtype = 'manual';
        $gradeitem->categoryid = $gradecategoryid;
        $gradeitem->courseid = $course->id;
        $gradeitem->idnumber = 'gi1';
        $gradeitem->insert();

        // Changing the category into a calculated grade category.
        $gradecategoryitem = grade_item::fetch(array('iteminstance' => $gradecategory->id));
        $gradecategoryitem->calculation = '=##gi' . $gradeitem->id . '##/2';
        $gradecategoryitem->grademax = 50;
        $gradecategoryitem->grademin = 15;
        $gradecategoryitem->update();

        // Setting a grade for the student.
        $grade = $gradeitem->get_grade($user->id, true);
        $grade->finalgrade = 50;
        $grade->update();

        grade_regrade_final_grades($course->id);
        $grade = grade_grade::fetch(array('itemid' => $gradecategoryitem->id, 'userid' => $user->id));
        $grade->rawgrademax = 100;
        $grade->rawgrademin = 0;
        $grade->update();
        $this->assertNotEquals($gradecategoryitem->grademax, $grade->rawgrademax);
        $this->assertNotEquals($gradecategoryitem->grademin, $grade->rawgrademin);

        // This is the function that we are testing. If we comment out this line, then the test fails because the grade items
        // are not flagged for regrading.
        upgrade_calculated_grade_items();
        grade_regrade_final_grades($course->id);

        $grade = grade_grade::fetch(array('itemid' => $gradecategoryitem->id, 'userid' => $user->id));

        $this->assertEquals($gradecategoryitem->grademax, $grade->rawgrademax);
        $this->assertEquals($gradecategoryitem->grademin, $grade->rawgrademin);
    }

    public function test_upgrade_course_tags() {
        global $DB, $CFG;

        $this->resetAfterTest();

        require_once($CFG->libdir . '/db/upgradelib.php');

        // Running upgrade script when there are no tags.
        upgrade_course_tags();
        $this->assertFalse($DB->record_exists('tag_instance', array()));

        // No course entries.
        $DB->insert_record('tag_instance', array('itemid' => 123, 'tagid' => 101, 'tiuserid' => 0,
            'itemtype' => 'post', 'component' => 'core', 'contextid' => 1));
        $DB->insert_record('tag_instance', array('itemid' => 333, 'tagid' => 103, 'tiuserid' => 1002,
            'itemtype' => 'post', 'component' => 'core', 'contextid' => 1));

        upgrade_course_tags();
        $records = array_values($DB->get_records('tag_instance', array(), 'id', '*'));
        $this->assertEquals(2, count($records));
        $this->assertEquals(123, $records[0]->itemid);
        $this->assertEquals(333, $records[1]->itemid);

        // Imagine we have tags 101, 102, 103, ... and courses 1, 2, 3, ... and users 1001, 1002, ... .
        $keys = array('itemid', 'tagid', 'tiuserid');
        $valuesets = array(
            array(1, 101, 0),
            array(1, 102, 0),

            array(2, 102, 0),
            array(2, 103, 1001),

            array(3, 103, 0),
            array(3, 103, 1001),

            array(3, 104, 1006),
            array(3, 104, 1001),
            array(3, 104, 1002),
        );

        foreach ($valuesets as $values) {
            $DB->insert_record('tag_instance', array_combine($keys, $values) +
                    array('itemtype' => 'course', 'component' => 'core', 'contextid' => 1));
        }

        upgrade_course_tags();
        // There are 8 records in 'tag_instance' table and 7 of them do not have tiuserid (except for one 'post').
        $records = array_values($DB->get_records('tag_instance', array(), 'id', '*'));
        $this->assertEquals(8, count($records));
        $this->assertEquals(7, $DB->count_records('tag_instance', array('tiuserid' => 0)));
        // Course 1 is mapped to tags 101 and 102.
        $this->assertEquals(array(101, 102), array_values($DB->get_fieldset_select('tag_instance', 'tagid',
                'itemtype = ? AND itemid = ? ORDER BY tagid', array('course', 1))));
        // Course 2 is mapped to tags 102 and 103.
        $this->assertEquals(array(102, 103), array_values($DB->get_fieldset_select('tag_instance', 'tagid',
                'itemtype = ? AND itemid = ? ORDER BY tagid', array('course', 2))));
        // Course 1 is mapped to tags 101 and 102.
        $this->assertEquals(array(103, 104), array_values($DB->get_fieldset_select('tag_instance', 'tagid',
                'itemtype = ? AND itemid = ? ORDER BY tagid', array('course', 3))));
    }
}