<?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_question;

use question_engine;

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

global $CFG;
require_once(__DIR__ . '/../lib.php');
require_once(__DIR__ . '/helpers.php');

/**
 * This file contains tests for the {@link question_attempt_iterator} class.
 *
 * @package    core_question
 * @category   test
 * @copyright  2009 The Open University
 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */
final class questionattemptiterator_test extends \advanced_testcase {
    private $quba;
    private $qas = array();
    private $iterator;

    protected function setUp(): void {
        parent::setUp();
        $this->quba = question_engine::make_questions_usage_by_activity('unit_test',
                \context_system::instance());
        $this->quba->set_preferred_behaviour('deferredfeedback');

        $slot = $this->quba->add_question(\test_question_maker::make_question('description'));
        $this->qas[$slot] = $this->quba->get_question_attempt($slot);

        $slot = $this->quba->add_question(\test_question_maker::make_question('description'));
        $this->qas[$slot] = $this->quba->get_question_attempt($slot);

        $this->iterator = $this->quba->get_attempt_iterator();
    }

    protected function tearDown(): void {
        $this->quba = null;
        $this->iterator = null;
        parent::tearDown();
    }

    public function test_foreach_loop(): void {
        $i = 1;
        foreach ($this->iterator as $key => $qa) {
            $this->assertEquals($i, $key);
            $this->assertSame($this->qas[$i], $qa);
            $i++;
        }
        $this->assertEquals(3, $i);
    }

    public function test_offsetExists_before_start(): void {
        $this->assertFalse(isset($this->iterator[0]));
    }

    public function test_offsetExists_at_start(): void {
        $this->assertTrue(isset($this->iterator[1]));
    }

    public function test_offsetExists_at_endt(): void {
        $this->assertTrue(isset($this->iterator[2]));
    }

    public function test_offsetExists_past_end(): void {
        $this->assertFalse(isset($this->iterator[3]));
    }

    public function test_offsetGet_before_start(): void {
        $this->expectException(\moodle_exception::class);
        $step = $this->iterator[0];
    }

    public function test_offsetGet_at_start(): void {
        $this->assertSame($this->qas[1], $this->iterator[1]);
    }

    public function test_offsetGet_at_end(): void {
        $this->assertSame($this->qas[2], $this->iterator[2]);
    }

    public function test_offsetGet_past_end(): void {
        $this->expectException(\moodle_exception::class);
        $step = $this->iterator[3];
    }

    public function test_cannot_set(): void {
        $this->expectException(\moodle_exception::class);
        $this->iterator[0] = null;
    }

    public function test_cannot_unset(): void {
        $this->expectException(\moodle_exception::class);
        unset($this->iterator[2]);
    }
}