class DateTest

class DateTest extends UnitTestCase {

  /**
   * The mocked entity type 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;

  /**
   * {@inheritdoc}
   */
  protected function setUp() : void {
    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');
    $this->languageManager
      ->expects($this
      ->any())
      ->method('getCurrentLanguage')
      ->willReturn(new Language([
      'id' => $this
        ->randomMachineName(2),
    ]));
    $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());
    $container
      ->set('language_manager', $this->languageManager);
    \Drupal::setContainer($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,
    ])
      ->onlyMethods([
      '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 static 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.
    // cspell:disable-next-line
    $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 = self::createTimestamp('2013-12-11 10:09:08');
    $timestamp = self::createTimestamp('2013-12-11 10:09:09');
    $options = [];

    // Mocks the formatDiff function of the DateFormatter object.
    $this->dateFormatterStub
      ->expects($this
      ->exactly(2))
      ->method('formatDiff')
      ->willReturnMap([
      [
        $timestamp,
        $request_time,
        $options,
        $expected,
      ],
      [
        $timestamp,
        $request_time,
        $options + [
          'return_as_object' => TRUE,
        ],
        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 = self::createTimestamp('2013-12-11 10:09:07');
    $request_time = self::createTimestamp('2013-12-11 10:09:08');
    $options = [];

    // Mocks the formatDiff function of the DateFormatter object.
    $this->dateFormatterStub
      ->expects($this
      ->exactly(2))
      ->method('formatDiff')
      ->willReturnMap([
      [
        $request_time,
        $timestamp,
        $options,
        $expected,
      ],
      [
        $request_time,
        $timestamp,
        $options + [
          'return_as_object' => TRUE,
        ],
        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(string $expected, int $max_age, int $timestamp1, int $timestamp2, array $options = []) : void {

    // 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 static function providerTestFormatDiff() : array {

    // This is the fixed request time in the test.
    $request_time = self::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,
        self::createTimestamp('2013-12-11 10:09:07'),
        $request_time,
      ],
      [
        '1 second',
        1,
        self::createTimestamp('2013-12-11 10:09:07'),
        $request_time,
      ],
      [
        '1 second',
        1,
        self::createTimestamp('2013-12-11 10:09:07'),
        $request_time,
        $granularity_3 + $langcode_en,
      ],
      [
        '1 second',
        1,
        self::createTimestamp('2013-12-11 10:09:07'),
        $request_time,
        $granularity_4 + $langcode_lolspeak,
      ],
      [
        '2 seconds',
        1,
        self::createTimestamp('2013-12-11 10:09:06'),
        $request_time,
      ],
      [
        '59 seconds',
        1,
        self::createTimestamp('2013-12-11 10:08:09'),
        $request_time,
      ],
      [
        '59 seconds',
        1,
        self::createTimestamp('2013-12-11 10:08:09'),
        $request_time,
      ],
      // Checks for minutes and possibly seconds.
      [
        '1 minute',
        60,
        self::createTimestamp('2013-12-11 10:08:08'),
        $request_time,
      ],
      [
        '1 minute',
        60,
        self::createTimestamp('2013-12-11 10:08:08'),
        $request_time,
      ],
      [
        '1 minute 1 second',
        1,
        self::createTimestamp('2013-12-11 10:08:07'),
        $request_time,
      ],
      [
        '1 minute 59 seconds',
        1,
        self::createTimestamp('2013-12-11 10:07:09'),
        $request_time,
      ],
      [
        '2 minutes',
        60,
        self::createTimestamp('2013-12-11 10:07:08'),
        $request_time,
      ],
      [
        '2 minutes 1 second',
        1,
        self::createTimestamp('2013-12-11 10:07:07'),
        $request_time,
      ],
      [
        '2 minutes 2 seconds',
        1,
        self::createTimestamp('2013-12-11 10:07:06'),
        $request_time,
      ],
      [
        '2 minutes 2 seconds',
        1,
        self::createTimestamp('2013-12-11 10:07:06'),
        $request_time,
        $granularity_3,
      ],
      [
        '2 minutes 2 seconds',
        1,
        self::createTimestamp('2013-12-11 10:07:06'),
        $request_time,
        $granularity_4,
      ],
      [
        '30 minutes',
        60,
        self::createTimestamp('2013-12-11 09:39:08'),
        $request_time,
      ],
      [
        '59 minutes 59 seconds',
        1,
        self::createTimestamp('2013-12-11 09:09:09'),
        $request_time,
      ],
      [
        '59 minutes 59 seconds',
        1,
        self::createTimestamp('2013-12-11 09:09:09'),
        $request_time,
      ],
      // Checks for hours and possibly minutes or seconds.
      [
        '1 hour',
        3600,
        self::createTimestamp('2013-12-11 09:09:08'),
        $request_time,
      ],
      [
        '1 hour',
        3600,
        self::createTimestamp('2013-12-11 09:09:08'),
        $request_time,
      ],
      [
        '1 hour',
        3600,
        self::createTimestamp('2013-12-11 09:09:07'),
        $request_time,
      ],
      [
        '1 hour',
        3600,
        self::createTimestamp('2013-12-11 09:09:06'),
        $request_time,
      ],
      [
        '1 hour 1 minute',
        60,
        self::createTimestamp('2013-12-11 09:08:08'),
        $request_time,
      ],
      [
        '1 hour 1 minute 1 second',
        1,
        self::createTimestamp('2013-12-11 09:08:07'),
        $request_time,
        $granularity_3,
      ],
      [
        '1 hour 1 minute 2 seconds',
        1,
        self::createTimestamp('2013-12-11 09:08:06'),
        $request_time,
        $granularity_4,
      ],
      [
        '1 hour 30 minutes',
        60,
        self::createTimestamp('2013-12-11 08:39:08'),
        $request_time,
      ],
      [
        '2 hours',
        3600,
        self::createTimestamp('2013-12-11 08:09:08'),
        $request_time,
      ],
      [
        '23 hours 59 minutes',
        60,
        self::createTimestamp('2013-12-10 10:10:08'),
        $request_time,
      ],
      // Checks for days and possibly hours, minutes or seconds.
      [
        '1 day',
        86400,
        self::createTimestamp('2013-12-10 10:09:08'),
        $request_time,
      ],
      [
        '1 day',
        86400,
        self::createTimestamp('2013-12-10 10:09:07'),
        $request_time,
      ],
      [
        '1 day 1 hour',
        3600,
        self::createTimestamp('2013-12-10 09:09:08'),
        $request_time,
      ],
      [
        '1 day 1 hour 1 minute',
        60,
        self::createTimestamp('2013-12-10 09:08:07'),
        $request_time,
        $granularity_3 + $langcode_en,
      ],
      [
        '1 day 1 hour 1 minute 1 second',
        1,
        self::createTimestamp('2013-12-10 09:08:07'),
        $request_time,
        $granularity_4 + $langcode_lolspeak,
      ],
      [
        '1 day 2 hours 2 minutes 2 seconds',
        1,
        self::createTimestamp('2013-12-10 08:07:06'),
        $request_time,
        $granularity_4,
      ],
      [
        '2 days',
        86400,
        self::createTimestamp('2013-12-09 10:09:08'),
        $request_time,
      ],
      [
        '2 days',
        86400,
        self::createTimestamp('2013-12-09 10:07:08'),
        $request_time,
      ],
      [
        '2 days 2 hours',
        3600,
        self::createTimestamp('2013-12-09 08:09:08'),
        $request_time,
      ],
      [
        '2 days 2 hours 2 minutes',
        60,
        self::createTimestamp('2013-12-09 08:07:06'),
        $request_time,
        $granularity_3 + $langcode_en,
      ],
      [
        '2 days 2 hours 2 minutes 2 seconds',
        1,
        self::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,
        self::createTimestamp('2013-12-04 10:09:08'),
        $request_time,
      ],
      [
        '1 week 1 day',
        86400,
        self::createTimestamp('2013-12-03 10:09:08'),
        $request_time,
      ],
      [
        '2 weeks',
        7 * 86400,
        self::createTimestamp('2013-11-27 10:09:08'),
        $request_time,
      ],
      [
        '2 weeks 2 days',
        86400,
        self::createTimestamp('2013-11-25 08:07:08'),
        $request_time,
      ],
      [
        '2 weeks 2 days 2 hours 2 minutes',
        60,
        self::createTimestamp('2013-11-25 08:07:08'),
        $request_time,
        $granularity_4,
      ],
      [
        '4 weeks',
        7 * 86400,
        self::createTimestamp('2013-11-13 10:09:08'),
        $request_time,
      ],
      [
        '4 weeks 1 day',
        86400,
        self::createTimestamp('2013-11-12 10:09:08'),
        $request_time,
      ],
      // Checks for months and possibly days, hours, minutes or seconds.
      [
        '1 month',
        30 * 86400,
        self::createTimestamp('2013-11-11 10:09:08'),
        $request_time,
      ],
      [
        '1 month',
        30 * 86400,
        self::createTimestamp('2013-11-11 10:09:07'),
        $request_time,
      ],
      [
        '1 month',
        30 * 86400,
        self::createTimestamp('2013-11-11 09:09:08'),
        $request_time,
      ],
      [
        '1 month',
        30 * 86400,
        self::createTimestamp('2013-11-11 09:08:07'),
        $request_time,
        $granularity_3,
      ],
      [
        '1 month',
        30 * 86400,
        self::createTimestamp('2013-11-11 09:08:07'),
        $request_time,
        $granularity_4,
      ],
      [
        '1 month 4 weeks',
        7 * 86400,
        self::createTimestamp('2013-10-13 10:09:08'),
        $request_time,
      ],
      [
        '1 month 4 weeks 1 day',
        86400,
        self::createTimestamp('2013-10-13 10:09:08'),
        $request_time,
        $granularity_3,
      ],
      [
        '1 month 4 weeks',
        7 * 86400,
        self::createTimestamp('2013-10-12 10:09:08'),
        $request_time,
      ],
      [
        '1 month 4 weeks 2 days',
        86400,
        self::createTimestamp('2013-10-12 10:09:08'),
        $request_time,
        $granularity_3,
      ],
      [
        '2 months',
        30 * 86400,
        self::createTimestamp('2013-10-11 10:09:08'),
        $request_time,
      ],
      [
        '2 months',
        30 * 86400,
        self::createTimestamp('2013-10-10 10:09:08'),
        $request_time,
      ],
      [
        '2 months',
        30 * 86400,
        self::createTimestamp('2013-10-09 08:07:06'),
        $request_time,
      ],
      [
        '2 months',
        30 * 86400,
        self::createTimestamp('2013-10-09 08:07:06'),
        $request_time,
        $granularity_3,
      ],
      [
        '2 months',
        30 * 86400,
        self::createTimestamp('2013-10-09 08:07:06'),
        $request_time,
        $granularity_4,
      ],
      [
        '6 months',
        30 * 86400,
        self::createTimestamp('2013-06-09 10:09:08'),
        $request_time,
      ],
      [
        '11 months',
        30 * 86400,
        self::createTimestamp('2013-01-11 07:09:08'),
        $request_time,
      ],
      [
        '11 months 4 weeks',
        7 * 86400,
        self::createTimestamp('2012-12-12 10:09:08'),
        $request_time,
      ],
      [
        '11 months 4 weeks 2 days',
        86400,
        self::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,
        self::createTimestamp('2012-12-11 10:09:08'),
        $request_time,
      ],
      [
        '1 year',
        365 * 86400,
        self::createTimestamp('2012-12-11 10:08:08'),
        $request_time,
      ],
      [
        '1 year',
        365 * 86400,
        self::createTimestamp('2012-12-10 10:09:08'),
        $request_time,
      ],
      [
        '2 years',
        365 * 86400,
        self::createTimestamp('2011-12-11 10:09:08'),
        $request_time,
      ],
      [
        '2 years',
        365 * 86400,
        self::createTimestamp('2011-12-11 10:07:08'),
        $request_time,
      ],
      [
        '2 years',
        365 * 86400,
        self::createTimestamp('2011-12-09 10:09:08'),
        $request_time,
      ],
      [
        '2 years 2 months',
        30 * 86400,
        self::createTimestamp('2011-10-09 08:07:06'),
        $request_time,
        $granularity_3,
      ],
      [
        '2 years 2 months',
        30 * 86400,
        self::createTimestamp('2011-10-09 08:07:06'),
        $request_time,
        $granularity_4,
      ],
      [
        '10 years',
        365 * 86400,
        self::createTimestamp('2003-12-11 10:09:08'),
        $request_time,
      ],
      [
        '100 years',
        365 * 86400,
        self::createTimestamp('1913-12-11 10:09:08'),
        $request_time,
      ],
      // Checks the non-strict option vs. strict (default).
      [
        '1 second',
        1,
        self::createTimestamp('2013-12-11 10:09:08'),
        self::createTimestamp('2013-12-11 10:09:07'),
        $non_strict,
      ],
      [
        '0 seconds',
        0,
        self::createTimestamp('2013-12-11 10:09:08'),
        self::createTimestamp('2013-12-11 10:09:07'),
      ],
      // Checks granularity limit.
      [
        '2 years 3 months 1 week',
        7 * 86400,
        self::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,
      ],
    ];
    $this
      ->assertEquals($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 that an RFC2822 formatted date always returns an English string.
   *
   * @see http://www.faqs.org/rfcs/rfc2822.html
   *
   * @covers ::format
   */
  public function testRfc2822DateFormat() : void {
    $timestamp = 1549110600;
    $langcodes = array_keys(LanguageManager::getStandardLanguageList());
    $langcodes[] = NULL;
    foreach ($langcodes as $langcode) {
      $formatted_date = $this->dateFormatter
        ->format($timestamp, 'custom', 'r', 'Europe/Berlin', $langcode);

      // Check that RFC2822 format date is returned regardless of langcode.
      $this
        ->assertSame('Sat, 02 Feb 2019 13:30:00 +0100', $formatted_date);
    }
  }

  /**
   * Creates a UNIX timestamp given a date and time string.
   *
   * @param string $dateTimeString
   *   The formatted date and time string. The format is year-month-day
   *   hour:minute:seconds (e.g. 2013-12-11 10:09:08).
   *
   * @return int
   *   The UNIX timestamp.
   */
  private static function createTimestamp(string $dateTimeString) : int {
    return \DateTime::createFromFormat('Y-m-d G:i:s', $dateTimeString)
      ->getTimestamp();
  }

}