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/>.

namespace core_availability;

/**

 * Unit tests for the condition tree class and related logic.

 *

 * @package core_availability

 * @copyright 2014 The Open University

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

 */

class tree_test extends \advanced_testcase {

    public function setUp(): void {

        // Load the mock classes so they can be used.

        require_once(__DIR__ . '/fixtures/mock_condition.php');

        require_once(__DIR__ . '/fixtures/mock_info.php');

    }

    /**

     * Tests constructing a tree with errors.

     */

    public function test_construct_errors() {

        try {

            new tree('frog');

            $this->fail();

        } catch (\coding_exception $e) {

            $this->assertStringContainsString('not object', $e->getMessage());

        }

        try {

            new tree((object)array());

            $this->fail();

        } catch (\coding_exception $e) {

            $this->assertStringContainsString('missing ->op', $e->getMessage());

        }

        try {

            new tree((object)array('op' => '*'));

            $this->fail();

        } catch (\coding_exception $e) {

            $this->assertStringContainsString('unknown ->op', $e->getMessage());

        }

        try {

            new tree((object)array('op' => '|'));

            $this->fail();

        } catch (\coding_exception $e) {

            $this->assertStringContainsString('missing ->show', $e->getMessage());

        }

        try {

            new tree((object)array('op' => '|', 'show' => 0));

            $this->fail();

        } catch (\coding_exception $e) {

            $this->assertStringContainsString('->show not bool', $e->getMessage());

        }

        try {

            new tree((object)array('op' => '&'));

            $this->fail();

        } catch (\coding_exception $e) {

            $this->assertStringContainsString('missing ->showc', $e->getMessage());

        }

        try {

            new tree((object)array('op' => '&', 'showc' => 0));

            $this->fail();

        } catch (\coding_exception $e) {

            $this->assertStringContainsString('->showc not array', $e->getMessage());

        }

        try {

            new tree((object)array('op' => '&', 'showc' => array(0)));

            $this->fail();

        } catch (\coding_exception $e) {

            $this->assertStringContainsString('->showc value not bool', $e->getMessage());

        }

        try {

            new tree((object)array('op' => '|', 'show' => true));

            $this->fail();

        } catch (\coding_exception $e) {

            $this->assertStringContainsString('missing ->c', $e->getMessage());

        }

        try {

            new tree((object)array('op' => '|', 'show' => true,

                    'c' => 'side'));

            $this->fail();

        } catch (\coding_exception $e) {

            $this->assertStringContainsString('->c not array', $e->getMessage());

        }

        try {

            new tree((object)array('op' => '|', 'show' => true,

                    'c' => array(3)));

            $this->fail();

        } catch (\coding_exception $e) {

            $this->assertStringContainsString('child not object', $e->getMessage());

        }

        try {

            new tree((object)array('op' => '|', 'show' => true,

                    'c' => array((object)array('type' => 'doesnotexist'))));

            $this->fail();

        } catch (\coding_exception $e) {

            $this->assertStringContainsString('Unknown condition type: doesnotexist', $e->getMessage());

        }

        try {

            new tree((object)array('op' => '|', 'show' => true,

                    'c' => array((object)array())));

            $this->fail();

        } catch (\coding_exception $e) {

            $this->assertStringContainsString('missing ->op', $e->getMessage());

        }

        try {

            new tree((object)array('op' => '&',

                    'c' => array((object)array('op' => '&', 'c' => array())),

                    'showc' => array(true, true)

                    ));

            $this->fail();

        } catch (\coding_exception $e) {

            $this->assertStringContainsString('->c, ->showc mismatch', $e->getMessage());

        }

    }

    /**

     * Tests constructing a tree with plugin that does not exist (ignored).

     */

    public function test_construct_ignore_missing_plugin() {

        // Construct a tree with & combination of one condition that doesn't exist.

        $tree = new tree(tree::get_root_json(array(

                (object)array('type' => 'doesnotexist')), tree::OP_OR), true);

        // Expected result is an empty tree with | condition, shown.

        $this->assertEquals('+|()', (string)$tree);

    }

    /**

     * Tests constructing a tree with subtrees using all available operators.

     */

    public function test_construct_just_trees() {

        $structure = tree::get_root_json(array(

                tree::get_nested_json(array(), tree::OP_OR),

                tree::get_nested_json(array(

                    tree::get_nested_json(array(), tree::OP_NOT_OR)), tree::OP_NOT_AND)),

                tree::OP_AND, array(true, true));

        $tree = new tree($structure);

        $this->assertEquals('&(+|(),+!&(!|()))', (string)$tree);

    }

    /**

     * Tests constructing tree using the mock plugin.

     */

    public function test_construct_with_mock_plugin() {

        $structure = tree::get_root_json(array(

                self::mock(array('a' => true, 'm' => ''))), tree::OP_OR);

        $tree = new tree($structure);

        $this->assertEquals('+|({mock:y,})', (string)$tree);

    }

    /**

     * Tests the check_available and get_result_information functions.

     */

    public function test_check_available() {

        global $USER;

        // Setup.

        $this->resetAfterTest();

        $info = new \core_availability\mock_info();

        $this->setAdminUser();

        $information = '';

        // No conditions.

        $structure = tree::get_root_json(array(), tree::OP_OR);

        list ($available, $information) = $this->get_available_results(

                $structure, $info, $USER->id);

        $this->assertTrue($available);

        // One condition set to yes.

        $structure->c = array(

                self::mock(array('a' => true)));

        list ($available, $information) = $this->get_available_results(

                $structure, $info, $USER->id);

        $this->assertTrue($available);

        // One condition set to no.

        $structure->c = array(

                self::mock(array('a' => false, 'm' => 'no')));

        list ($available, $information) = $this->get_available_results(

                $structure, $info, $USER->id);

        $this->assertFalse($available);

        $this->assertEquals('SA: no', $information);

        // Two conditions, OR, resolving as true.

        $structure->c = array(

                self::mock(array('a' => false, 'm' => 'no')),

                self::mock(array('a' => true)));

        list ($available, $information) = $this->get_available_results(

                $structure, $info, $USER->id);

        $this->assertTrue($available);

        $this->assertEquals('', $information);

        // Two conditions, OR, resolving as false.

        $structure->c = array(

                self::mock(array('a' => false, 'm' => 'no')),

                self::mock(array('a' => false, 'm' => 'way')));

        list ($available, $information) = $this->get_available_results(

                $structure, $info, $USER->id);

        $this->assertFalse($available);

        $this->assertMatchesRegularExpression('~any of.*no.*way~', $information);

        // Two conditions, OR, resolving as false, no display.

        $structure->show = false;

        list ($available, $information) = $this->get_available_results(

                $structure, $info, $USER->id);

        $this->assertFalse($available);

        $this->assertEquals('', $information);

        // Two conditions, AND, resolving as true.

        $structure->op = '&';

        unset($structure->show);

        $structure->showc = array(true, true);

        $structure->c = array(

                self::mock(array('a' => true)),

                self::mock(array('a' => true)));

        list ($available, $information) = $this->get_available_results(

                $structure, $info, $USER->id);

        $this->assertTrue($available);

        // Two conditions, AND, one false.

        $structure->c = array(

                self::mock(array('a' => false, 'm' => 'wom')),

                self::mock(array('a' => true, 'm' => '')));

        list ($available, $information) = $this->get_available_results(

                $structure, $info, $USER->id);

        $this->assertFalse($available);

        $this->assertEquals('SA: wom', $information);

        // Two conditions, AND, both false.

        $structure->c = array(

                self::mock(array('a' => false, 'm' => 'wom')),

                self::mock(array('a' => false, 'm' => 'bat')));

        list ($available, $information) = $this->get_available_results(

                $structure, $info, $USER->id);

        $this->assertFalse($available);

        $this->assertMatchesRegularExpression('~wom.*bat~', $information);

        // Two conditions, AND, both false, show turned off for one. When

        // show is turned off, that means if you don't have that condition

        // you don't get to see anything at all.

        $structure->showc[0] = false;

        list ($available, $information) = $this->get_available_results(

                $structure, $info, $USER->id);

        $this->assertFalse($available);

        $this->assertEquals('', $information);

        $structure->showc[0] = true;

        // Two conditions, NOT OR, both false.

        $structure->op = '!|';

        list ($available, $information) = $this->get_available_results(

                $structure, $info, $USER->id);

        $this->assertTrue($available);

        // Two conditions, NOT OR, one true.

        $structure->c[0]->a = true;

        list ($available, $information) = $this->get_available_results(

                $structure, $info, $USER->id);

        $this->assertFalse($available);

        $this->assertEquals('SA: !wom', $information);

        // Two conditions, NOT OR, both true.

        $structure->c[1]->a = true;

        list ($available, $information) = $this->get_available_results(

                $structure, $info, $USER->id);

        $this->assertFalse($available);

        $this->assertMatchesRegularExpression('~!wom.*!bat~', $information);

        // Two conditions, NOT AND, both true.

        $structure->op = '!&';

        unset($structure->showc);

        $structure->show = true;

        list ($available, $information) = $this->get_available_results(

                $structure, $info, $USER->id);

        $this->assertFalse($available);

        $this->assertMatchesRegularExpression('~any of.*!wom.*!bat~', $information);

        // Two conditions, NOT AND, one true.

        $structure->c[1]->a = false;

        list ($available, $information) = $this->get_available_results(

                $structure, $info, $USER->id);

        $this->assertTrue($available);

        // Nested NOT conditions; true.

        $structure->c = array(

                tree::get_nested_json(array(

                    self::mock(array('a' => true, 'm' => 'no'))), tree::OP_NOT_AND));

        list ($available, $information) = $this->get_available_results(

                $structure, $info, $USER->id);

        $this->assertTrue($available);

        // Nested NOT conditions; false (note no ! in message).

        $structure->c[0]->c[0]->a = false;

        list ($available, $information) = $this->get_available_results(

                $structure, $info, $USER->id);

        $this->assertFalse($available);

        $this->assertEquals('SA: no', $information);

        // Nested condition groups, message test.

        $structure->op = '|';

        $structure->c = array(

                tree::get_nested_json(array(

                    self::mock(array('a' => false, 'm' => '1')),

                    self::mock(array('a' => false, 'm' => '2'))

                    ), tree::OP_AND),

                self::mock(array('a' => false, 'm' => 3)));

        list ($available, $information) = $this->get_available_results(

                $structure, $info, $USER->id);

        $this->assertFalse($available);

        $this->assertMatchesRegularExpression('~<ul.*<ul.*<li.*1.*<li.*2.*</ul>.*<li.*3~', $information);

    }

    /**

     * Shortcut function to check availability and also get information.

     *

     * @param \stdClass $structure Tree structure

     * @param \core_availability\info $info Location info

     * @param int $userid User id

     */

    protected function get_available_results($structure, \core_availability\info $info, $userid) {

        global $PAGE, $OUTPUT;

        $tree = new tree($structure);

        $result = $tree->check_available(false, $info, true, $userid);

        $information = $tree->get_result_information($info, $result);

        if (!is_string($information)) {

            $renderable = new \core_availability\output\availability_info($information);

            $information = str_replace(array("\r", "\n"), '', $OUTPUT->render($renderable));

        }

        return array($result->is_available(), $information);

    }

    /**

     * Shortcut function to render the full availability information.

     *

     * @param \stdClass $structure Tree structure

     * @param \core_availability\info $info Location info

     */

    protected function render_full_information($structure, \core_availability\info $info) {

        global $OUTPUT;

        $tree = new tree($structure);

        $information = $tree->get_full_information($info);

        $renderable = new \core_availability\output\availability_info($information);

        $html = $OUTPUT->render($renderable);

        return str_replace(array("\r", "\n"), '', $html);

    }

    /**

     * Tests the is_available_for_all() function.

     */

    public function test_is_available_for_all() {

        // Empty tree is always available.

        $structure = tree::get_root_json(array(), tree::OP_OR);

        $tree = new tree($structure);

        $this->assertTrue($tree->is_available_for_all());

        // Tree with normal item in it, not always available.

        $structure->c[0] = (object)array('type' => 'mock');

        $tree = new tree($structure);

        $this->assertFalse($tree->is_available_for_all());

        // OR tree with one always-available item.

        $structure->c[1] = self::mock(array('all' => true));

        $tree = new tree($structure);

        $this->assertTrue($tree->is_available_for_all());

        // AND tree with one always-available and one not.

        $structure->op = '&';

        $structure->showc = array(true, true);

        unset($structure->show);

        $tree = new tree($structure);

        $this->assertFalse($tree->is_available_for_all());

        // Test NOT conditions (items not always-available).

        $structure->op = '!&';

        $structure->show = true;

        unset($structure->showc);

        $tree = new tree($structure);

        $this->assertFalse($tree->is_available_for_all());

        // Test again with one item always-available for NOT mode.

        $structure->c[1]->allnot = true;

        $tree = new tree($structure);

        $this->assertTrue($tree->is_available_for_all());

    }

    /**

     * Tests the get_full_information() function.

     */

    public function test_get_full_information() {

        global $PAGE;

        // Setup.

        $info = new \core_availability\mock_info();

        // No conditions.

        $structure = tree::get_root_json(array(), tree::OP_OR);

        $tree = new tree($structure);

        $this->assertEquals('', $tree->get_full_information($info));

        // Condition (normal and NOT).

        $structure->c = array(

                self::mock(array('m' => 'thing')));

        $tree = new tree($structure);

        $this->assertEquals('SA: [FULL]thing',

                $tree->get_full_information($info));

        $structure->op = '!&';

        $tree = new tree($structure);

        $this->assertEquals('SA: ![FULL]thing',

                $tree->get_full_information($info));

        // Complex structure.

        $structure->op = '|';

        $structure->c = array(

                tree::get_nested_json(array(

                    self::mock(array('m' => '1')),

                    self::mock(array('m' => '2'))), tree::OP_AND),

                self::mock(array('m' => 3)));

        $this->assertMatchesRegularExpression('~<ul.*<ul.*<li.*1.*<li.*2.*</ul>.*<li.*3~',

                $this->render_full_information($structure, $info));

        // Test intro messages before list. First, OR message.

        $structure->c = array(

                self::mock(array('m' => '1')),

                self::mock(array('m' => '2'))

        );

        $this->assertMatchesRegularExpression('~Not available unless any of:.*<ul~',

                $this->render_full_information($structure, $info));

        // Now, OR message when not shown.

        $structure->show = false;

        $this->assertMatchesRegularExpression('~hidden.*<ul~',

                $this->render_full_information($structure, $info));

        // AND message.

        $structure->op = '&';

        unset($structure->show);

        $structure->showc = array(false, false);

        $this->assertMatchesRegularExpression('~Not available unless:.*<ul~',

                $this->render_full_information($structure, $info));

        // Hidden markers on items.

        $this->assertMatchesRegularExpression('~1.*hidden.*2.*hidden~',

                $this->render_full_information($structure, $info));

        // Hidden markers on child tree and items.

        $structure->c[1] = tree::get_nested_json(array(

                self::mock(array('m' => '2')),

                self::mock(array('m' => '3'))), tree::OP_AND);

        $this->assertMatchesRegularExpression('~1.*hidden.*All of \(hidden.*2.*3~',

                $this->render_full_information($structure, $info));

        $structure->c[1]->op = '|';

        $this->assertMatchesRegularExpression('~1.*hidden.*Any of \(hidden.*2.*3~',

                $this->render_full_information($structure, $info));

        // Hidden markers on single-item display, AND and OR.

        $structure->showc = array(false);

        $structure->c = array(

                self::mock(array('m' => '1'))

        );

        $tree = new tree($structure);

        $this->assertMatchesRegularExpression('~1.*hidden~',

                $tree->get_full_information($info));

        unset($structure->showc);

        $structure->show = false;

        $structure->op = '|';

        $tree = new tree($structure);

        $this->assertMatchesRegularExpression('~1.*hidden~',

                $tree->get_full_information($info));

        // Hidden marker if single item is tree.

        $structure->c[0] = tree::get_nested_json(array(

                self::mock(array('m' => '1')),

                self::mock(array('m' => '2'))), tree::OP_AND);

        $this->assertMatchesRegularExpression('~Not available \(hidden.*1.*2~',

                $this->render_full_information($structure, $info));

        // Single item tree containing single item.

        unset($structure->c[0]->c[1]);

        $tree = new tree($structure);

        $this->assertMatchesRegularExpression('~SA.*1.*hidden~',

                $tree->get_full_information($info));

    }

    /**

     * Tests the is_empty() function.

     */

    public function test_is_empty() {

        // Tree with nothing in should be empty.

        $structure = tree::get_root_json(array(), tree::OP_OR);

        $tree = new tree($structure);

        $this->assertTrue($tree->is_empty());

        // Tree with something in is not empty.

        $structure = tree::get_root_json(array(self::mock(array('m' => '1'))), tree::OP_OR);

        $tree = new tree($structure);

        $this->assertFalse($tree->is_empty());

    }

    /**

     * Tests the get_all_children() function.

     */

    public function test_get_all_children() {

        // Create a tree with nothing in.

        $structure = tree::get_root_json(array(), tree::OP_OR);

        $tree1 = new tree($structure);

        // Create second tree with complex structure.

        $structure->c = array(

                tree::get_nested_json(array(

                    self::mock(array('m' => '1')),

                    self::mock(array('m' => '2'))

                ), tree::OP_OR),

                self::mock(array('m' => 3)));

        $tree2 = new tree($structure);

        // Check list of conditions from both trees.

        $this->assertEquals(array(), $tree1->get_all_children('core_availability\condition'));

        $result = $tree2->get_all_children('core_availability\condition');

        $this->assertEquals(3, count($result));

        $this->assertEquals('{mock:n,1}', (string)$result[0]);

        $this->assertEquals('{mock:n,2}', (string)$result[1]);

        $this->assertEquals('{mock:n,3}', (string)$result[2]);

        // Check specific type, should give same results.

        $result2 = $tree2->get_all_children('availability_mock\condition');

        $this->assertEquals($result, $result2);

    }

    /**

     * Tests the update_dependency_id() function.

     */

    public function test_update_dependency_id() {

        // Create tree with structure of 3 mocks.

        $structure = tree::get_root_json(array(

                tree::get_nested_json(array(

                    self::mock(array('table' => 'frogs', 'id' => 9)),

                    self::mock(array('table' => 'zombies', 'id' => 9))

                )),

                self::mock(array('table' => 'frogs', 'id' => 9))));

        // Get 'before' value.

        $tree = new tree($structure);

        $before = $tree->save();

        // Try replacing a table or id that isn't used.

        $this->assertFalse($tree->update_dependency_id('toads', 9, 13));

        $this->assertFalse($tree->update_dependency_id('frogs', 7, 8));

        $this->assertEquals($before, $tree->save());

        // Replace the zombies one.

        $this->assertTrue($tree->update_dependency_id('zombies', 9, 666));

        $after = $tree->save();

        $this->assertEquals(666, $after->c[0]->c[1]->id);

        // And the frogs one.

        $this->assertTrue($tree->update_dependency_id('frogs', 9, 3));

        $after = $tree->save();

        $this->assertEquals(3, $after->c[0]->c[0]->id);

        $this->assertEquals(3, $after->c[1]->id);

    }

    /**

     * Tests the filter_users function.

     */

    public function test_filter_users() {

        $info = new \core_availability\mock_info();

        $checker = new capability_checker($info->get_context());

        // Don't need to create real users in database, just use these ids.

        $users = array(1 => null, 2 => null, 3 => null);

        // Test basic tree with one condition that doesn't filter.

        $structure = tree::get_root_json(array(self::mock(array())));

        $tree = new tree($structure);

        $result = $tree->filter_user_list($users, false, $info, $checker);

        ksort($result);

        $this->assertEquals(array(1, 2, 3), array_keys($result));

        // Now a tree with one condition that filters.

        $structure = tree::get_root_json(array(self::mock(array('filter' => array(2, 3)))));

        $tree = new tree($structure);

        $result = $tree->filter_user_list($users, false, $info, $checker);

        ksort($result);

        $this->assertEquals(array(2, 3), array_keys($result));

        // Tree with two conditions that both filter (|).

        $structure = tree::get_root_json(array(

                self::mock(array('filter' => array(3))),

                self::mock(array('filter' => array(1)))), tree::OP_OR);

        $tree = new tree($structure);

        $result = $tree->filter_user_list($users, false, $info, $checker);

        ksort($result);

        $this->assertEquals(array(1, 3), array_keys($result));

        // Tree with OR condition one of which doesn't filter.

        $structure = tree::get_root_json(array(

                self::mock(array('filter' => array(3))),

                self::mock(array())), tree::OP_OR);

        $tree = new tree($structure);

        $result = $tree->filter_user_list($users, false, $info, $checker);

        ksort($result);

        $this->assertEquals(array(1, 2, 3), array_keys($result));

        // Tree with two condition that both filter (&).

        $structure = tree::get_root_json(array(

                self::mock(array('filter' => array(2, 3))),

                self::mock(array('filter' => array(1, 2)))));

        $tree = new tree($structure);

        $result = $tree->filter_user_list($users, false, $info, $checker);

        ksort($result);

        $this->assertEquals(array(2), array_keys($result));

        // Tree with child tree with NOT condition.

        $structure = tree::get_root_json(array(

                tree::get_nested_json(array(

                    self::mock(array('filter' => array(1)))), tree::OP_NOT_AND)));

        $tree = new tree($structure);

        $result = $tree->filter_user_list($users, false, $info, $checker);

        ksort($result);

        $this->assertEquals(array(2, 3), array_keys($result));

    }

    /**

     * Tests the get_json methods in tree (which are mainly for use in testing

     * but might be used elsewhere).

     */

    public function test_get_json() {

        // Create a simple child object (fake).

        $child = (object)array('type' => 'fake');

        $childstr = json_encode($child);

        // Minimal case.

        $this->assertEquals(

                (object)array('op' => '&', 'c' => array()),

                tree::get_nested_json(array()));

        // Children and different operator.

        $this->assertEquals(

                (object)array('op' => '|', 'c' => array($child, $child)),

                tree::get_nested_json(array($child, $child), tree::OP_OR));

        // Root empty.

        $this->assertEquals('{"op":"&","c":[],"showc":[]}',

                json_encode(tree::get_root_json(array(), tree::OP_AND)));

        // Root with children (multi-show operator).

        $this->assertEquals('{"op":"&","c":[' . $childstr . ',' . $childstr .

                    '],"showc":[true,true]}',

                json_encode(tree::get_root_json(array($child, $child), tree::OP_AND)));

        // Root with children (single-show operator).

        $this->assertEquals('{"op":"|","c":[' . $childstr . ',' . $childstr .

                    '],"show":true}',

                json_encode(tree::get_root_json(array($child, $child), tree::OP_OR)));

        // Root with children (specified show boolean).

        $this->assertEquals('{"op":"&","c":[' . $childstr . ',' . $childstr .

                    '],"showc":[false,false]}',

                json_encode(tree::get_root_json(array($child, $child), tree::OP_AND, false)));

        // Root with children (specified show array).

        $this->assertEquals('{"op":"&","c":[' . $childstr . ',' . $childstr .

                    '],"showc":[true,false]}',

                json_encode(tree::get_root_json(array($child, $child), tree::OP_AND, array(true, false))));

    }

    /**

     * Tests the behaviour of the counter in unique_sql_parameter().

     *

     * There was a problem with static counters used to implement a sequence of

     * parameter placeholders (MDL-53481). As always with static variables, it

     * is a bit tricky to unit test the behaviour reliably as it depends on the

     * actual tests executed and also their order.

     *

     * To minimise risk of false expected behaviour, this test method should be

     * first one where {@link core_availability\tree::get_user_list_sql()} is

     * used. We also use higher number of condition instances to increase the

     * risk of the counter collision, should there remain a problem.

     */

    public function test_unique_sql_parameter_behaviour() {

        global $DB;

        $this->resetAfterTest();

        $generator = $this->getDataGenerator();

        // Create a test course with multiple groupings and groups and a student in each of them.

        $course = $generator->create_course();

        $user = $generator->create_user();

        $studentroleid = $DB->get_field('role', 'id', array('shortname' => 'student'));

        $generator->enrol_user($user->id, $course->id, $studentroleid);

        // The total number of groupings and groups must not be greater than 61.

        // There is a limit in MySQL on the max number of joined tables.

        $groups = [];

        for ($i = 0; $i < 25; $i++) {

            $group = $generator->create_group(array('courseid' => $course->id));

            groups_add_member($group, $user);

            $groups[] = $group;

        }

        $groupings = [];

        for ($i = 0; $i < 25; $i++) {

            $groupings[] = $generator->create_grouping(array('courseid' => $course->id));

        }

        foreach ($groupings as $grouping) {

            foreach ($groups as $group) {

                groups_assign_grouping($grouping->id, $group->id);

            }

        }

        $info = new \core_availability\mock_info($course);

        // Make a huge tree with 'AND' of all groups and groupings conditions.

        $conditions = [];

        foreach ($groups as $group) {

            $conditions[] = \availability_group\condition::get_json($group->id);

        }

        foreach ($groupings as $groupingid) {

            $conditions[] = \availability_grouping\condition::get_json($grouping->id);

        }

        shuffle($conditions);

        $tree = new tree(tree::get_root_json($conditions));

        list($sql, $params) = $tree->get_user_list_sql(false, $info, false);

        // This must not throw exception.

        $DB->fix_sql_params($sql, $params);

    }

    /**

     * Tests get_user_list_sql.

     */

    public function test_get_user_list_sql() {

        global $DB;

        $this->resetAfterTest();

        $generator = $this->getDataGenerator();

        // Create a test course with 2 groups and users in each combination of them.

        $course = $generator->create_course();

        $group1 = $generator->create_group(array('courseid' => $course->id));

        $group2 = $generator->create_group(array('courseid' => $course->id));

        $userin1 = $generator->create_user();

        $userin2 = $generator->create_user();

        $userinboth = $generator->create_user();

        $userinneither = $generator->create_user();

        $studentroleid = $DB->get_field('role', 'id', array('shortname' => 'student'));

        foreach (array($userin1, $userin2, $userinboth, $userinneither) as $user) {

            $generator->enrol_user($user->id, $course->id, $studentroleid);

        }

        groups_add_member($group1, $userin1);

        groups_add_member($group2, $userin2);

        groups_add_member($group1, $userinboth);

        groups_add_member($group2, $userinboth);

        $info = new \core_availability\mock_info($course);

        // Tree with single group condition.

        $tree = new tree(tree::get_root_json(array(

            \availability_group\condition::get_json($group1->id)

            )));

        list($sql, $params) = $tree->get_user_list_sql(false, $info, false);

        $result = $DB->get_fieldset_sql($sql, $params);

        sort($result);

        $this->assertEquals(array($userin1->id, $userinboth->id), $result);

        // Tree with 'AND' of both group conditions.

        $tree = new tree(tree::get_root_json(array(

            \availability_group\condition::get_json($group1->id),

            \availability_group\condition::get_json($group2->id)

        )));

        list($sql, $params) = $tree->get_user_list_sql(false, $info, false);

        $result = $DB->get_fieldset_sql($sql, $params);

        sort($result);

        $this->assertEquals(array($userinboth->id), $result);

        // Tree with 'AND' of both group conditions.

        $tree = new tree(tree::get_root_json(array(

            \availability_group\condition::get_json($group1->id),

            \availability_group\condition::get_json($group2->id)

        ), tree::OP_OR));

        list($sql, $params) = $tree->get_user_list_sql(false, $info, false);

        $result = $DB->get_fieldset_sql($sql, $params);

        sort($result);

        $this->assertEquals(array($userin1->id, $userin2->id, $userinboth->id), $result);

        // Check with flipped logic (NOT above level of tree).

        list($sql, $params) = $tree->get_user_list_sql(true, $info, false);

        $result = $DB->get_fieldset_sql($sql, $params);

        sort($result);

        $this->assertEquals(array($userinneither->id), $result);

        // Tree with 'OR' of group conditions and a non-filtering condition.

        // The non-filtering condition should mean that ALL users are included.

        $tree = new tree(tree::get_root_json(array(

            \availability_group\condition::get_json($group1->id),

            \availability_date\condition::get_json(\availability_date\condition::DIRECTION_UNTIL, 3)

        ), tree::OP_OR));

        list($sql, $params) = $tree->get_user_list_sql(false, $info, false);

        $this->assertEquals('', $sql);

        $this->assertEquals(array(), $params);

    }

    /**

     * Utility function to build the PHP structure representing a mock condition.

     *

     * @param array $params Mock parameters

     * @return \stdClass Structure object

     */

    protected static function mock(array $params) {

        $params['type'] = 'mock';

        return (object)$params;

    }

}