class DateTest

class DateTest extends UnitTestCase {
    
    /**
     * The mocked entity manager.
     *
     * @var \Drupal\Core\Entity\EntityTypeManagerInterface|\PHPUnit\Framework\MockObject\MockObject
     */
    protected $entityTypeManager;
    
    /**
     * The mocked language manager.
     *
     * @var \Drupal\Core\Language\LanguageManagerInterface|\PHPUnit\Framework\MockObject\MockObject
     */
    protected $languageManager;
    
    /**
     * The mocked string translation.
     *
     * @var \Drupal\Core\StringTranslation\TranslationInterface|\PHPUnit\Framework\MockObject\MockObject
     */
    protected $stringTranslation;
    
    /**
     * The mocked string translation.
     *
     * @var \Symfony\Component\HttpFoundation\RequestStack|\PHPUnit\Framework\MockObject\MockObject
     */
    protected $requestStack;
    
    /**
     * The mocked date formatter class.
     *
     * @var \Drupal\Core\Datetime\DateFormatter
     */
    protected $dateFormatter;
    
    /**
     * The date formatter class where methods can be stubbed.
     *
     * @var \Drupal\Core\Datetime\DateFormatter|\PHPUnit\Framework\MockObject\MockObject
     */
    protected $dateFormatterStub;
    protected function setUp() {
        parent::setUp();
        $entity_storage = $this->createMock('Drupal\\Core\\Entity\\EntityStorageInterface');
        $this->entityTypeManager = $this->createMock('Drupal\\Core\\Entity\\EntityTypeManagerInterface');
        $this->entityTypeManager
            ->expects($this->any())
            ->method('getStorage')
            ->with('date_format')
            ->willReturn($entity_storage);
        $this->languageManager = $this->createMock('Drupal\\Core\\Language\\LanguageManagerInterface');
        $this->stringTranslation = $this->createMock('Drupal\\Core\\StringTranslation\\TranslationInterface');
        $this->requestStack = $this->createMock('Symfony\\Component\\HttpFoundation\\RequestStack');
        $config_factory = $this->getConfigFactoryStub([
            'system.date' => [
                'country' => [
                    'default' => 'GB',
                ],
            ],
        ]);
        $container = new ContainerBuilder();
        $container->set('config.factory', $config_factory);
        $container->set('string_translation', $this->getStringTranslationStub());
        \Drupal::setContainer($container);
        $this->dateFormatter = new DateFormatter($this->entityTypeManager, $this->languageManager, $this->stringTranslation, $this->getConfigFactoryStub(), $this->requestStack);
        $this->dateFormatterStub = $this->getMockBuilder('\\Drupal\\Core\\Datetime\\DateFormatter')
            ->setConstructorArgs([
            $this->entityTypeManager,
            $this->languageManager,
            $this->stringTranslation,
            $this->getConfigFactoryStub(),
            $this->requestStack,
        ])
            ->setMethods([
            'formatDiff',
        ])
            ->getMock();
    }
    
    /**
     * Tests the formatInterval method.
     *
     * @dataProvider providerTestFormatInterval
     *
     * @covers ::formatInterval
     */
    public function testFormatInterval($interval, $granularity, $expected, $langcode = NULL) {
        // Mocks a simple formatPlural implementation.
        $this->stringTranslation
            ->expects($this->any())
            ->method('translateString')
            ->willReturnCallback(function (TranslatableMarkup $arg) {
            return $arg->getUntranslatedString();
        });
        // Check if the granularity is specified.
        if ($granularity) {
            $result = $this->dateFormatter
                ->formatInterval($interval, $granularity, $langcode);
        }
        else {
            $result = $this->dateFormatter
                ->formatInterval($interval);
        }
        $this->assertEquals(new TranslatableMarkup($expected, [], [
            'langcode' => $langcode,
        ], $this->stringTranslation), $result);
    }
    
    /**
     * Provides some test data for the format interval test.
     */
    public function providerTestFormatInterval() {
        $data = [
            // Checks for basic seconds.
[
                1,
                1,
                '1 sec',
            ],
            [
                1,
                2,
                '1 sec',
            ],
            [
                2,
                1,
                '2 sec',
            ],
            [
                2,
                2,
                '2 sec',
            ],
            // Checks for minutes with seconds.
[
                61,
                1,
                '1 min',
            ],
            [
                61,
                2,
                '1 min 1 sec',
            ],
            [
                62,
                2,
                '1 min 2 sec',
            ],
            [
                121,
                1,
                '2 min',
            ],
            [
                121,
                2,
                '2 min 1 sec',
            ],
            // Check for hours with minutes and seconds.
[
                3601,
                1,
                '1 hour',
            ],
            [
                3601,
                2,
                '1 hour',
            ],
            // Check for higher units.
[
                86401,
                1,
                '1 day',
            ],
            [
                604800,
                1,
                '1 week',
            ],
            [
                2592000 * 2,
                1,
                '2 months',
            ],
            [
                31536000 * 2,
                1,
                '2 years',
            ],
            // Check for a complicated one with months weeks and days.
[
                2592000 * 2 + 604800 * 3 + 86400 * 4,
                3,
                '2 months 3 weeks 4 days',
            ],
            // Check for the langcode.
[
                61,
                1,
                '1 min',
                'xxx-lolspeak',
            ],
            // Check with an unspecified granularity.
[
                61,
                NULL,
                '1 min 1 sec',
            ],
        ];
        return $data;
    }
    
    /**
     * Tests the formatInterval method for 0 second.
     */
    public function testFormatIntervalZeroSecond() {
        $result = $this->dateFormatter
            ->formatInterval(0, 1, 'xxx-lolspeak');
        $this->assertEquals(new TranslatableMarkup('0 sec', [], [
            'langcode' => 'xxx-lolspeak',
        ], $this->stringTranslation), $result);
    }
    
    /**
     * Tests the getSampleDateFormats method.
     *
     * @covers \Drupal\Core\Datetime\DateFormatter::getSampleDateFormats
     */
    public function testGetSampleDateFormats() {
        $timestamp = strtotime('2015-03-22 14:23:00');
        $expected = $this->dateFormatter
            ->getSampleDateFormats('en', $timestamp, 'Australia/Sydney');
        // Removed characters related to timezone 'e' and 'T', as test does not have
        // timezone set.
        $date_characters = 'dDjlNSwzWFmMntLoYyaABgGhHisuIOPZcrU';
        $date_chars = str_split($date_characters);
        foreach ($date_chars as $val) {
            $this->assertEquals($expected[$val], date($val, $timestamp));
        }
    }
    
    /**
     * Tests the formatTimeDiffUntil method.
     *
     * @covers ::formatTimeDiffUntil
     */
    public function testFormatTimeDiffUntil() {
        $expected = '1 second';
        $request_time = $this->createTimestamp('2013-12-11 10:09:08');
        $timestamp = $this->createTimestamp('2013-12-11 10:09:09');
        $options = [];
        // Mocks the formatDiff function of the dateformatter object.
        $this->dateFormatterStub
            ->expects($this->at(0))
            ->method('formatDiff')
            ->with($timestamp, $request_time, $options)
            ->will($this->returnValue($expected));
        $this->dateFormatterStub
            ->expects($this->at(1))
            ->method('formatDiff')
            ->with($timestamp, $request_time, $options + [
            'return_as_object' => TRUE,
        ])
            ->will($this->returnValue(new FormattedDateDiff('1 second', 1)));
        $request = Request::createFromGlobals();
        $request->server
            ->set('REQUEST_TIME', $request_time);
        // Mocks a the request stack getting the current request.
        $this->requestStack
            ->expects($this->any())
            ->method('getCurrentRequest')
            ->willReturn($request);
        $this->assertEquals($expected, $this->dateFormatterStub
            ->formatTimeDiffSince($timestamp, $options));
        $options['return_as_object'] = TRUE;
        $expected_object = new FormattedDateDiff('1 second', 1);
        $this->assertEquals($expected_object, $this->dateFormatterStub
            ->formatTimeDiffSince($timestamp, $options));
    }
    
    /**
     * Tests the formatTimeDiffSince method.
     *
     * @covers ::formatTimeDiffSince
     */
    public function testFormatTimeDiffSince() {
        $expected = '1 second';
        $timestamp = $this->createTimestamp('2013-12-11 10:09:07');
        $request_time = $this->createTimestamp('2013-12-11 10:09:08');
        $options = [];
        // Mocks the formatDiff function of the dateformatter object.
        $this->dateFormatterStub
            ->expects($this->at(0))
            ->method('formatDiff')
            ->with($request_time, $timestamp, $options)
            ->will($this->returnValue($expected));
        $this->dateFormatterStub
            ->expects($this->at(1))
            ->method('formatDiff')
            ->with($request_time, $timestamp, $options + [
            'return_as_object' => TRUE,
        ])
            ->will($this->returnValue(new FormattedDateDiff('1 second', 1)));
        $request = Request::createFromGlobals();
        $request->server
            ->set('REQUEST_TIME', $request_time);
        // Mocks a the request stack getting the current request.
        $this->requestStack
            ->expects($this->any())
            ->method('getCurrentRequest')
            ->willReturn($request);
        $this->assertEquals($expected, $this->dateFormatterStub
            ->formatTimeDiffUntil($timestamp, $options));
        $options['return_as_object'] = TRUE;
        $expected_object = new FormattedDateDiff('1 second', 1);
        $this->assertEquals($expected_object, $this->dateFormatterStub
            ->formatTimeDiffUntil($timestamp, $options));
    }
    
    /**
     * Tests the formatDiff method.
     *
     * @dataProvider providerTestFormatDiff
     *
     * @covers ::formatDiff
     */
    public function testformatDiff($expected, $max_age, $timestamp1, $timestamp2, $options = []) {
        // Mocks a simple translateString implementation.
        $this->stringTranslation
            ->expects($this->any())
            ->method('translateString')
            ->willReturnCallback(function (TranslatableMarkup $arg) {
            return $arg->getUntranslatedString();
        });
        if (isset($options['langcode'])) {
            $expected_markup = new TranslatableMarkup($expected, [], [
                'langcode' => $options['langcode'],
            ], $this->stringTranslation);
        }
        else {
            $expected_markup = new TranslatableMarkup($expected, [], [], $this->stringTranslation);
        }
        $this->assertEquals($expected_markup, $this->dateFormatter
            ->formatDiff($timestamp1, $timestamp2, $options));
        $options['return_as_object'] = TRUE;
        $expected_object = new FormattedDateDiff($expected, $max_age);
        $this->assertEquals($expected_object, $this->dateFormatter
            ->formatDiff($timestamp1, $timestamp2, $options));
    }
    
    /**
     * Data provider for testformatDiff().
     */
    public function providerTestFormatDiff() {
        // This is the fixed request time in the test.
        $request_time = $this->createTimestamp('2013-12-11 10:09:08');
        $granularity_3 = [
            'granularity' => 3,
        ];
        $granularity_4 = [
            'granularity' => 4,
        ];
        $langcode_en = [
            'langcode' => 'en',
        ];
        $langcode_lolspeak = [
            'langcode' => 'xxx-lolspeak',
        ];
        $non_strict = [
            'strict' => FALSE,
        ];
        $data = [
            // Checks for equal timestamps.
[
                '0 seconds',
                0,
                $request_time,
                $request_time,
            ],
            // Checks for seconds only.
[
                '1 second',
                1,
                $this->createTimestamp('2013-12-11 10:09:07'),
                $request_time,
            ],
            [
                '1 second',
                1,
                $this->createTimestamp('2013-12-11 10:09:07'),
                $request_time,
            ],
            [
                '1 second',
                1,
                $this->createTimestamp('2013-12-11 10:09:07'),
                $request_time,
                $granularity_3 + $langcode_en,
            ],
            [
                '1 second',
                1,
                $this->createTimestamp('2013-12-11 10:09:07'),
                $request_time,
                $granularity_4 + $langcode_lolspeak,
            ],
            [
                '2 seconds',
                1,
                $this->createTimestamp('2013-12-11 10:09:06'),
                $request_time,
            ],
            [
                '59 seconds',
                1,
                $this->createTimestamp('2013-12-11 10:08:09'),
                $request_time,
            ],
            [
                '59 seconds',
                1,
                $this->createTimestamp('2013-12-11 10:08:09'),
                $request_time,
            ],
            // Checks for minutes and possibly seconds.
[
                '1 minute',
                60,
                $this->createTimestamp('2013-12-11 10:08:08'),
                $request_time,
            ],
            [
                '1 minute',
                60,
                $this->createTimestamp('2013-12-11 10:08:08'),
                $request_time,
            ],
            [
                '1 minute 1 second',
                1,
                $this->createTimestamp('2013-12-11 10:08:07'),
                $request_time,
            ],
            [
                '1 minute 59 seconds',
                1,
                $this->createTimestamp('2013-12-11 10:07:09'),
                $request_time,
            ],
            [
                '2 minutes',
                60,
                $this->createTimestamp('2013-12-11 10:07:08'),
                $request_time,
            ],
            [
                '2 minutes 1 second',
                1,
                $this->createTimestamp('2013-12-11 10:07:07'),
                $request_time,
            ],
            [
                '2 minutes 2 seconds',
                1,
                $this->createTimestamp('2013-12-11 10:07:06'),
                $request_time,
            ],
            [
                '2 minutes 2 seconds',
                1,
                $this->createTimestamp('2013-12-11 10:07:06'),
                $request_time,
                $granularity_3,
            ],
            [
                '2 minutes 2 seconds',
                1,
                $this->createTimestamp('2013-12-11 10:07:06'),
                $request_time,
                $granularity_4,
            ],
            [
                '30 minutes',
                60,
                $this->createTimestamp('2013-12-11 09:39:08'),
                $request_time,
            ],
            [
                '59 minutes 59 seconds',
                1,
                $this->createTimestamp('2013-12-11 09:09:09'),
                $request_time,
            ],
            [
                '59 minutes 59 seconds',
                1,
                $this->createTimestamp('2013-12-11 09:09:09'),
                $request_time,
            ],
            // Checks for hours and possibly minutes or seconds.
[
                '1 hour',
                3600,
                $this->createTimestamp('2013-12-11 09:09:08'),
                $request_time,
            ],
            [
                '1 hour',
                3600,
                $this->createTimestamp('2013-12-11 09:09:08'),
                $request_time,
            ],
            [
                '1 hour',
                3600,
                $this->createTimestamp('2013-12-11 09:09:07'),
                $request_time,
            ],
            [
                '1 hour',
                3600,
                $this->createTimestamp('2013-12-11 09:09:06'),
                $request_time,
            ],
            [
                '1 hour 1 minute',
                60,
                $this->createTimestamp('2013-12-11 09:08:08'),
                $request_time,
            ],
            [
                '1 hour 1 minute 1 second',
                1,
                $this->createTimestamp('2013-12-11 09:08:07'),
                $request_time,
                $granularity_3,
            ],
            [
                '1 hour 1 minute 2 seconds',
                1,
                $this->createTimestamp('2013-12-11 09:08:06'),
                $request_time,
                $granularity_4,
            ],
            [
                '1 hour 30 minutes',
                60,
                $this->createTimestamp('2013-12-11 08:39:08'),
                $request_time,
            ],
            [
                '2 hours',
                3600,
                $this->createTimestamp('2013-12-11 08:09:08'),
                $request_time,
            ],
            [
                '23 hours 59 minutes',
                60,
                $this->createTimestamp('2013-12-10 10:10:08'),
                $request_time,
            ],
            // Checks for days and possibly hours, minutes or seconds.
[
                '1 day',
                86400,
                $this->createTimestamp('2013-12-10 10:09:08'),
                $request_time,
            ],
            [
                '1 day',
                86400,
                $this->createTimestamp('2013-12-10 10:09:07'),
                $request_time,
            ],
            [
                '1 day 1 hour',
                3600,
                $this->createTimestamp('2013-12-10 09:09:08'),
                $request_time,
            ],
            [
                '1 day 1 hour 1 minute',
                60,
                $this->createTimestamp('2013-12-10 09:08:07'),
                $request_time,
                $granularity_3 + $langcode_en,
            ],
            [
                '1 day 1 hour 1 minute 1 second',
                1,
                $this->createTimestamp('2013-12-10 09:08:07'),
                $request_time,
                $granularity_4 + $langcode_lolspeak,
            ],
            [
                '1 day 2 hours 2 minutes 2 seconds',
                1,
                $this->createTimestamp('2013-12-10 08:07:06'),
                $request_time,
                $granularity_4,
            ],
            [
                '2 days',
                86400,
                $this->createTimestamp('2013-12-09 10:09:08'),
                $request_time,
            ],
            [
                '2 days',
                86400,
                $this->createTimestamp('2013-12-09 10:07:08'),
                $request_time,
            ],
            [
                '2 days 2 hours',
                3600,
                $this->createTimestamp('2013-12-09 08:09:08'),
                $request_time,
            ],
            [
                '2 days 2 hours 2 minutes',
                60,
                $this->createTimestamp('2013-12-09 08:07:06'),
                $request_time,
                $granularity_3 + $langcode_en,
            ],
            [
                '2 days 2 hours 2 minutes 2 seconds',
                1,
                $this->createTimestamp('2013-12-09 08:07:06'),
                $request_time,
                $granularity_4 + $langcode_lolspeak,
            ],
            // Checks for weeks and possibly days, hours, minutes or seconds.
[
                '1 week',
                7 * 86400,
                $this->createTimestamp('2013-12-04 10:09:08'),
                $request_time,
            ],
            [
                '1 week 1 day',
                86400,
                $this->createTimestamp('2013-12-03 10:09:08'),
                $request_time,
            ],
            [
                '2 weeks',
                7 * 86400,
                $this->createTimestamp('2013-11-27 10:09:08'),
                $request_time,
            ],
            [
                '2 weeks 2 days',
                86400,
                $this->createTimestamp('2013-11-25 08:07:08'),
                $request_time,
            ],
            [
                '2 weeks 2 days 2 hours 2 minutes',
                60,
                $this->createTimestamp('2013-11-25 08:07:08'),
                $request_time,
                $granularity_4,
            ],
            [
                '4 weeks',
                7 * 86400,
                $this->createTimestamp('2013-11-13 10:09:08'),
                $request_time,
            ],
            [
                '4 weeks 1 day',
                86400,
                $this->createTimestamp('2013-11-12 10:09:08'),
                $request_time,
            ],
            // Checks for months and possibly days, hours, minutes or seconds.
[
                '1 month',
                30 * 86400,
                $this->createTimestamp('2013-11-11 10:09:08'),
                $request_time,
            ],
            [
                '1 month',
                30 * 86400,
                $this->createTimestamp('2013-11-11 10:09:07'),
                $request_time,
            ],
            [
                '1 month',
                30 * 86400,
                $this->createTimestamp('2013-11-11 09:09:08'),
                $request_time,
            ],
            [
                '1 month',
                30 * 86400,
                $this->createTimestamp('2013-11-11 09:08:07'),
                $request_time,
                $granularity_3,
            ],
            [
                '1 month',
                30 * 86400,
                $this->createTimestamp('2013-11-11 09:08:07'),
                $request_time,
                $granularity_4,
            ],
            [
                '1 month 4 weeks',
                7 * 86400,
                $this->createTimestamp('2013-10-13 10:09:08'),
                $request_time,
            ],
            [
                '1 month 4 weeks 1 day',
                86400,
                $this->createTimestamp('2013-10-13 10:09:08'),
                $request_time,
                $granularity_3,
            ],
            [
                '1 month 4 weeks',
                7 * 86400,
                $this->createTimestamp('2013-10-12 10:09:08'),
                $request_time,
            ],
            [
                '1 month 4 weeks 2 days',
                86400,
                $this->createTimestamp('2013-10-12 10:09:08'),
                $request_time,
                $granularity_3,
            ],
            [
                '2 months',
                30 * 86400,
                $this->createTimestamp('2013-10-11 10:09:08'),
                $request_time,
            ],
            [
                '2 months',
                30 * 86400,
                $this->createTimestamp('2013-10-10 10:09:08'),
                $request_time,
            ],
            [
                '2 months',
                30 * 86400,
                $this->createTimestamp('2013-10-09 08:07:06'),
                $request_time,
            ],
            [
                '2 months',
                30 * 86400,
                $this->createTimestamp('2013-10-09 08:07:06'),
                $request_time,
                $granularity_3,
            ],
            [
                '2 months',
                30 * 86400,
                $this->createTimestamp('2013-10-09 08:07:06'),
                $request_time,
                $granularity_4,
            ],
            [
                '6 months',
                30 * 86400,
                $this->createTimestamp('2013-06-09 10:09:08'),
                $request_time,
            ],
            [
                '11 months',
                30 * 86400,
                $this->createTimestamp('2013-01-11 07:09:08'),
                $request_time,
            ],
            [
                '11 months 4 weeks',
                7 * 86400,
                $this->createTimestamp('2012-12-12 10:09:08'),
                $request_time,
            ],
            [
                '11 months 4 weeks 2 days',
                86400,
                $this->createTimestamp('2012-12-12 10:09:08'),
                $request_time,
                $granularity_3,
            ],
            // Checks for years and possibly months, days, hours, minutes or seconds.
[
                '1 year',
                365 * 86400,
                $this->createTimestamp('2012-12-11 10:09:08'),
                $request_time,
            ],
            [
                '1 year',
                365 * 86400,
                $this->createTimestamp('2012-12-11 10:08:08'),
                $request_time,
            ],
            [
                '1 year',
                365 * 86400,
                $this->createTimestamp('2012-12-10 10:09:08'),
                $request_time,
            ],
            [
                '2 years',
                365 * 86400,
                $this->createTimestamp('2011-12-11 10:09:08'),
                $request_time,
            ],
            [
                '2 years',
                365 * 86400,
                $this->createTimestamp('2011-12-11 10:07:08'),
                $request_time,
            ],
            [
                '2 years',
                365 * 86400,
                $this->createTimestamp('2011-12-09 10:09:08'),
                $request_time,
            ],
            [
                '2 years 2 months',
                30 * 86400,
                $this->createTimestamp('2011-10-09 08:07:06'),
                $request_time,
                $granularity_3,
            ],
            [
                '2 years 2 months',
                30 * 86400,
                $this->createTimestamp('2011-10-09 08:07:06'),
                $request_time,
                $granularity_4,
            ],
            [
                '10 years',
                365 * 86400,
                $this->createTimestamp('2003-12-11 10:09:08'),
                $request_time,
            ],
            [
                '100 years',
                365 * 86400,
                $this->createTimestamp('1913-12-11 10:09:08'),
                $request_time,
            ],
            // Checks the non-strict option vs. strict (default).
[
                '1 second',
                1,
                $this->createTimestamp('2013-12-11 10:09:08'),
                $this->createTimestamp('2013-12-11 10:09:07'),
                $non_strict,
            ],
            [
                '0 seconds',
                0,
                $this->createTimestamp('2013-12-11 10:09:08'),
                $this->createTimestamp('2013-12-11 10:09:07'),
            ],
            // Checks granularity limit.
[
                '2 years 3 months 1 week',
                7 * 86400,
                $this->createTimestamp('2011-08-30 11:15:57'),
                $request_time,
                $granularity_3,
            ],
        ];
        return $data;
    }
    
    /**
     * Tests FormattedDateDiff.
     *
     * @covers \Drupal\Core\Datetime\FormattedDateDiff::toRenderable
     * @covers \Drupal\Core\Datetime\FormattedDateDiff::getString
     * @covers \Drupal\Core\Datetime\FormattedDateDiff::getCacheMaxAge
     */
    public function testFormattedDateDiff() {
        $string = '10 minutes';
        $max_age = 60;
        $object = new FormattedDateDiff($string, $max_age);
        // Test conversion to a render array.
        $expected = [
            '#markup' => $string,
            '#cache' => [
                'max-age' => $max_age,
            ],
        ];
        $this->assertArrayEquals($expected, $object->toRenderable());
        // Test retrieving the formatted time difference string.
        $this->assertEquals($string, $object->getString());
        // Test applying cacheability data to an existing build.
        $build = [];
        CacheableMetadata::createFromObject($object)->applyTo($build);
        $this->assertEquals($max_age, $build['#cache']['max-age']);
    }
    
    /**
     * Tests FormattedDateDiff.
     *
     * @covers \Drupal\Core\Datetime\FormattedDateDiff::getMaxAge
     * @group legacy
     * @expectedDeprecation Drupal\Core\Datetime\FormattedDateDiff::getMaxAge() is deprecated in drupal:8.1.9 and is removed from drupal:9.0.0. Use \Drupal\Core\Datetime\FormattedDateDiff::getCacheMaxAge() instead. See https://www.drupal.org/node/2783545
     */
    public function testLegacyMaxAgeFormattedDateDiff() {
        $string = '10 minutes';
        $max_age = 60;
        $object = new FormattedDateDiff($string, $max_age);
        $this->assertSame($object->getCacheMaxAge(), $object->getMaxAge());
    }
    
    /**
     * Creates a UNIX timestamp given a date and time string in the format
     * year-month-day hour:minute:seconds (e.g. 2013-12-11 10:09:08).
     *
     * @param string $dateTimeString
     *   The formatted date and time string.
     *
     * @return int
     *   The UNIX timestamp.
     */
    private function createTimestamp($dateTimeString) {
        return \DateTime::createFromFormat('Y-m-d G:i:s', $dateTimeString)->getTimestamp();
    }

}