class DateTimePlusTest

class DateTimePlusTest extends TestCase {
    
    /**
     * Tests creating dates from string and array input.
     *
     * @param mixed $input
     *   Input argument for DateTimePlus.
     * @param string $timezone
     *   Timezone argument for DateTimePlus.
     * @param string $expected
     *   Expected output from DateTimePlus::format().
     *
     * @dataProvider providerTestDates
     */
    public function testDates($input, $timezone, $expected) : void {
        $date = new DateTimePlus($input, $timezone);
        $value = $date->format('c');
        if (is_array($input)) {
            $input = var_export($input, TRUE);
        }
        $this->assertEquals($expected, $value, sprintf("Test new DateTimePlus(%s, %s): should be %s, found %s.", $input, $timezone, $expected, $value));
    }
    
    /**
     * Tests creating dates from string and array input.
     *
     * @param mixed $input
     *   Input argument for DateTimePlus.
     * @param string $timezone
     *   Timezone argument for DateTimePlus.
     * @param string $expected
     *   Expected output from DateTimePlus::format().
     *
     * @dataProvider providerTestDateArrays
     */
    public function testDateArrays($input, $timezone, $expected) : void {
        $date = DateTimePlus::createFromArray($input, $timezone);
        $value = $date->format('c');
        if (is_array($input)) {
            $input = var_export($input, TRUE);
        }
        $this->assertEquals($expected, $value, sprintf("Test new DateTimePlus(%s, %s): should be %s, found %s.", $input, $timezone, $expected, $value));
    }
    
    /**
     * Tests date diffs.
     *
     * @param mixed $input1
     *   A DateTimePlus object.
     * @param mixed $input2
     *   Date argument for DateTimePlus::diff method.
     * @param bool $absolute
     *   Absolute flag for DateTimePlus::diff method.
     * @param \DateInterval $expected
     *   The expected result of the DateTimePlus::diff operation.
     *
     * @dataProvider providerTestDateDiff
     */
    public function testDateDiff($input1, $input2, $absolute, \DateInterval $expected) : void {
        $interval = $input1->diff($input2, $absolute);
        $this->assertEquals($interval, $expected);
    }
    
    /**
     * Tests date diff exception caused by invalid input.
     *
     * @param mixed $input1
     *   A DateTimePlus object.
     * @param mixed $input2
     *   Date argument for DateTimePlus::diff method.
     * @param bool $absolute
     *   Absolute flag for DateTimePlus::diff method.
     *
     * @dataProvider providerTestInvalidDateDiff
     */
    public function testInvalidDateDiff($input1, $input2, $absolute) : void {
        $this->expectException(\BadMethodCallException::class);
        $this->expectExceptionMessage('Method Drupal\\Component\\Datetime\\DateTimePlus::diff expects parameter 1 to be a \\DateTime or \\Drupal\\Component\\Datetime\\DateTimePlus object');
        $interval = $input1->diff($input2, $absolute);
    }
    
    /**
     * Tests creating dates from invalid array input.
     *
     * @param mixed $input
     *   Input argument for DateTimePlus.
     * @param string $timezone
     *   Timezone argument for DateTimePlus.
     * @param string $class
     *   The Exception subclass to expect to be thrown.
     *
     * @dataProvider providerTestInvalidDateArrays
     */
    public function testInvalidDateArrays($input, $timezone, $class) : void {
        $this->expectException($class);
        $this->assertInstanceOf('\\Drupal\\Component\\DateTimePlus', DateTimePlus::createFromArray($input, $timezone));
    }
    
    /**
     * Tests DateTimePlus::checkArray().
     *
     * @param array $array
     *   Input argument for DateTimePlus::checkArray().
     * @param bool $expected
     *   The expected result of DateTimePlus::checkArray().
     *
     * @dataProvider providerTestCheckArray
     */
    public function testCheckArray(array $array, $expected) : void {
        $this->assertSame($expected, DateTimePlus::checkArray($array));
    }
    
    /**
     * Tests creating dates from timestamps, and manipulating timezones.
     *
     * @param int $input
     *   Input argument for DateTimePlus::createFromTimestamp().
     * @param array $initial
     *   An array containing:
     *   - 'timezone_initial' - Timezone argument for DateTimePlus.
     *   - 'format_initial' - Format argument for DateTimePlus.
     *   - 'expected_initial_date' - Expected output from DateTimePlus::format().
     *   - 'expected_initial_timezone' - Expected output from
     *      DateTimePlus::getTimeZone()::getName().
     *   - 'expected_initial_offset' - Expected output from DateTimePlus::getOffset().
     * @param array $transform
     *   An array containing:
     *   - 'timezone_transform' - Argument to transform date to another timezone via
     *     DateTimePlus::setTimezone().
     *   - 'format_transform' - Format argument to use when transforming date to
     *     another timezone.
     *   - 'expected_transform_date' - Expected output from DateTimePlus::format(),
     *     after timezone transform.
     *   - 'expected_transform_timezone' - Expected output from
     *     DateTimePlus::getTimeZone()::getName(), after timezone transform.
     *   - 'expected_transform_offset' - Expected output from
     *      DateTimePlus::getOffset(), after timezone transform.
     *
     * @dataProvider providerTestTimestamp
     */
    public function testTimestamp($input, array $initial, array $transform) : void {
        // Initialize a new date object.
        $date = DateTimePlus::createFromTimestamp($input, $initial['timezone']);
        $this->assertDateTimestamp($date, $input, $initial, $transform);
    }
    
    /**
     * Tests creating dates from datetime strings.
     *
     * @param string $input
     *   Input argument for DateTimePlus().
     * @param array $initial
     *   @see testTimestamp()
     * @param array $transform
     *   @see testTimestamp()
     *
     * @dataProvider providerTestDateTimestamp
     */
    public function testDateTimestamp($input, array $initial, array $transform) : void {
        // Initialize a new date object.
        $date = new DateTimePlus($input, $initial['timezone']);
        $this->assertDateTimestamp($date, $input, $initial, $transform);
    }
    
    /**
     * Asserts a DateTimePlus value.
     *
     * @param \Drupal\Component\Datetime\DateTimePlus $date
     *   DateTimePlus to test.
     * @param string|int $input
     *   The original input passed to the test method.
     * @param array $initial
     *   @see testTimestamp()
     * @param array $transform
     *   @see testTimestamp()
     *
     * @internal
     */
    public function assertDateTimestamp(DateTimePlus $date, string|int $input, array $initial, array $transform) : void {
        // Check format.
        $value = $date->format($initial['format']);
        $this->assertEquals($initial['expected_date'], $value, sprintf("Test new DateTimePlus(%s, %s): should be %s, found %s.", $input, $initial['timezone'], $initial['expected_date'], $value));
        // Check timezone name.
        $value = $date->getTimeZone()
            ->getName();
        $this->assertEquals($initial['expected_timezone'], $value, sprintf("The current timezone is %s: should be %s.", $value, $initial['expected_timezone']));
        // Check offset.
        $value = $date->getOffset();
        $this->assertEquals($initial['expected_offset'], $value, sprintf("The current offset is %s: should be %s.", $value, $initial['expected_offset']));
        // Transform the date to another timezone.
        $date->setTimezone(new \DateTimeZone($transform['timezone']));
        // Check transformed format.
        $value = $date->format($transform['format']);
        $this->assertEquals($transform['expected_date'], $value, sprintf("Test \$date->setTimezone(new \\DateTimeZone(%s)): should be %s, found %s.", $transform['timezone'], $transform['expected_date'], $value));
        // Check transformed timezone.
        $value = $date->getTimeZone()
            ->getName();
        $this->assertEquals($transform['expected_timezone'], $value, sprintf("The current timezone should be %s, found %s.", $transform['expected_timezone'], $value));
        // Check transformed offset.
        $value = $date->getOffset();
        $this->assertEquals($transform['expected_offset'], $value, sprintf("The current offset should be %s, found %s.", $transform['expected_offset'], $value));
    }
    
    /**
     * Tests creating dates from format strings.
     *
     * @param string $input
     *   Input argument for DateTimePlus.
     * @param string $timezone
     *   Timezone argument for DateTimePlus.
     * @param string $format
     *   PHP date() type format for parsing the input.
     * @param string $format_date
     *   Format argument for DateTimePlus::format().
     * @param string $expected
     *   Expected output from DateTimePlus::format().
     *
     * @dataProvider providerTestDateFormat
     */
    public function testDateFormat($input, $timezone, $format, $format_date, $expected) : void {
        $date = DateTimePlus::createFromFormat($format, $input, $timezone);
        $value = $date->format($format_date);
        $this->assertEquals($expected, $value, sprintf("Test new DateTimePlus(%s, %s, %s): should be %s, found %s.", $input, $timezone, $format, $expected, $value));
    }
    
    /**
     * Tests invalid date handling.
     *
     * @param mixed $input
     *   Input argument for DateTimePlus.
     * @param string $timezone
     *   Timezone argument for DateTimePlus.
     * @param string $format
     *   Format argument for DateTimePlus.
     * @param string $message
     *   Message to print if no errors are thrown by the invalid dates.
     * @param string $class
     *   The Exception subclass to expect to be thrown.
     *
     * @dataProvider providerTestInvalidDates
     */
    public function testInvalidDates($input, $timezone, $format, $message, $class) : void {
        $this->expectException($class);
        DateTimePlus::createFromFormat($format, $input, $timezone);
    }
    
    /**
     * Tests that DrupalDateTime can detect the right timezone to use.
     *
     * When specified or not.
     *
     * @param mixed $input
     *   Input argument for DateTimePlus.
     * @param mixed $timezone
     *   Timezone argument for DateTimePlus.
     * @param string $expected_timezone
     *   Expected timezone returned from DateTimePlus::getTimezone::getName().
     * @param string $message
     *   Message to print on test failure.
     *
     * @dataProvider providerTestDateTimezone
     */
    public function testDateTimezone($input, $timezone, $expected_timezone, $message) : void {
        $date = new DateTimePlus($input, $timezone);
        $timezone = $date->getTimezone()
            ->getName();
        $this->assertEquals($timezone, $expected_timezone, $message);
    }
    
    /**
     * Tests that DrupalDateTime can detect the correct timezone to use.
     *
     * But only when the DrupalDateTime is constructed from a datetime object.
     */
    public function testDateTimezoneWithDateTimeObject() : void {
        // Create a date object with another date object.
        $input = new \DateTime('now', new \DateTimeZone('Pacific/Midway'));
        $timezone = NULL;
        $expected_timezone = 'Pacific/Midway';
        $message = 'DateTimePlus uses the specified timezone if provided.';
        $date = DateTimePlus::createFromDateTime($input, $timezone);
        $timezone = $date->getTimezone()
            ->getName();
        $this->assertEquals($timezone, $expected_timezone, $message);
    }
    
    /**
     * Provides data for date tests.
     *
     * @return array
     *   An array of arrays, each containing the input parameters for
     *   DateTimePlusTest::testDates().
     *
     * @see DateTimePlusTest::testDates()
     */
    public static function providerTestDates() {
        $dates = [
            // String input.
            // Create date object from datetime string.
[
                '2009-03-07 10:30',
                'America/Chicago',
                '2009-03-07T10:30:00-06:00',
            ],
            // Same during daylight savings time.
[
                '2009-06-07 10:30',
                'America/Chicago',
                '2009-06-07T10:30:00-05:00',
            ],
            // Create date object from date string.
[
                '2009-03-07',
                'America/Chicago',
                '2009-03-07T00:00:00-06:00',
            ],
            // Same during daylight savings time.
[
                '2009-06-07',
                'America/Chicago',
                '2009-06-07T00:00:00-05:00',
            ],
            // Create date object from date string.
[
                '2009-03-07 10:30',
                'Australia/Canberra',
                '2009-03-07T10:30:00+11:00',
            ],
            // Same during daylight savings time.
[
                '2009-06-07 10:30',
                'Australia/Canberra',
                '2009-06-07T10:30:00+10:00',
            ],
        ];
        // On 32-bit systems, timestamps are limited to 1901-2038.
        if (PHP_INT_SIZE > 4) {
            // Create a date object in the distant past.
            // @see https://www.drupal.org/node/2795489#comment-12127088
            // Note that this date is after the United States standardized its
            // timezones.
            $dates[] = [
                '1883-11-19 10:30',
                'America/Chicago',
                '1883-11-19T10:30:00-06:00',
            ];
            // Create a date object in the far future.
            $dates[] = [
                '2345-01-02 02:04',
                'UTC',
                '2345-01-02T02:04:00+00:00',
            ];
        }
        return $dates;
    }
    
    /**
     * Provides data for date tests.
     *
     * @return array
     *   An array of arrays, each containing the input parameters for
     *   DateTimePlusTest::testDates().
     *
     * @see DateTimePlusTest::testDates()
     */
    public static function providerTestDateArrays() {
        $dates = [
            // Array input.
            // Create date object from date array, date only.
[
                [
                    'year' => 2010,
                    'month' => 2,
                    'day' => 28,
                ],
                'America/Chicago',
                '2010-02-28T00:00:00-06:00',
            ],
            // Create date object from date array with hour.
[
                [
                    'year' => 2010,
                    'month' => 2,
                    'day' => 28,
                    'hour' => 10,
                ],
                'America/Chicago',
                '2010-02-28T10:00:00-06:00',
            ],
            // Create date object from date array, date only.
[
                [
                    'year' => 2010,
                    'month' => 2,
                    'day' => 28,
                ],
                'Europe/Berlin',
                '2010-02-28T00:00:00+01:00',
            ],
            // Create date object from date array with hour.
[
                [
                    'year' => 2010,
                    'month' => 2,
                    'day' => 28,
                    'hour' => 10,
                ],
                'Europe/Berlin',
                '2010-02-28T10:00:00+01:00',
            ],
        ];
        // On 32-bit systems, timestamps are limited to 1901-2038.
        if (PHP_INT_SIZE > 4) {
            // Create a date object in the distant past.
            // @see https://www.drupal.org/node/2795489#comment-12127088
            // Note that this date is after the United States standardized its
            // timezones.
            $dates[] = [
                [
                    'year' => 1883,
                    'month' => 11,
                    'day' => 19,
                ],
                'America/Chicago',
                '1883-11-19T00:00:00-06:00',
            ];
            // Create a date object in the far future.
            $dates[] = [
                [
                    'year' => 2345,
                    'month' => 1,
                    'day' => 2,
                ],
                'UTC',
                '2345-01-02T00:00:00+00:00',
            ];
        }
        return $dates;
    }
    
    /**
     * Provides data for testDateFormats.
     *
     * @return array
     *   An array of arrays, each containing:
     *   - 'input' - Input to DateTimePlus.
     *   - 'timezone' - Timezone for DateTimePlus.
     *   - 'format' - Date format for DateTimePlus.
     *   - 'format_date' - Date format for use in $date->format() method.
     *   - 'expected' - The expected return from DateTimePlus.
     *
     * @see testDateFormats()
     */
    public static function providerTestDateFormat() {
        return [
            // Create a year-only date.
[
                '2009',
                NULL,
                'Y',
                'Y',
                '2009',
            ],
            // Create a month and year-only date.
[
                '2009-10',
                NULL,
                'Y-m',
                'Y-m',
                '2009-10',
            ],
            // Create a time-only date.
[
                'T10:30:00',
                NULL,
                '\\TH:i:s',
                'H:i:s',
                '10:30:00',
            ],
            // Create a time-only date.
[
                '10:30:00',
                NULL,
                'H:i:s',
                'H:i:s',
                '10:30:00',
            ],
        ];
    }
    
    /**
     * Provides data for testInvalidDates.
     *
     * @return array
     *   An array of arrays, each containing:
     *   - 'input' - Input for DateTimePlus.
     *   - 'timezone' - Timezone for DateTimePlus.
     *   - 'format' - Format for DateTimePlus.
     *   - 'message' - Message to display on failure.
     *
     * @see testInvalidDates
     */
    public static function providerTestInvalidDates() {
        return [
            // Test for invalid month names when we are using a short version
            // of the month.
[
                '23 abc 2012',
                NULL,
                'd M Y',
                "23 abc 2012 contains an invalid month name and did not produce errors.",
                \InvalidArgumentException::class,
            ],
            // Test for invalid hour.
[
                '0000-00-00T45:30:00',
                NULL,
                'Y-m-d\\TH:i:s',
                "0000-00-00T45:30:00 contains an invalid hour and did not produce errors.",
                \UnexpectedValueException::class,
            ],
            // Test for invalid day.
[
                '0000-00-99T05:30:00',
                NULL,
                'Y-m-d\\TH:i:s',
                "0000-00-99T05:30:00 contains an invalid day and did not produce errors.",
                \UnexpectedValueException::class,
            ],
            // Test for invalid month.
[
                '0000-75-00T15:30:00',
                NULL,
                'Y-m-d\\TH:i:s',
                "0000-75-00T15:30:00 contains an invalid month and did not produce errors.",
                \UnexpectedValueException::class,
            ],
            // Test for invalid year.
[
                '11-08-01T15:30:00',
                NULL,
                'Y-m-d\\TH:i:s',
                "11-08-01T15:30:00 contains an invalid year and did not produce errors.",
                \UnexpectedValueException::class,
            ],
        ];
    }
    
    /**
     * Data provider for testInvalidDateArrays.
     *
     * @return array
     *   An array of arrays, each containing:
     *   - 'input' - Input for DateTimePlus.
     *   - 'timezone' - Timezone for DateTimePlus.
     *
     * @see testInvalidDateArrays
     */
    public static function providerTestInvalidDateArrays() {
        return [
            // One year larger than the documented upper limit of checkdate().
[
                [
                    'year' => 32768,
                    'month' => 1,
                    'day' => 8,
                    'hour' => 8,
                    'minute' => 0,
                    'second' => 0,
                ],
                'America/Chicago',
                \InvalidArgumentException::class,
            ],
            // One year smaller than the documented lower limit of checkdate().
[
                [
                    'year' => 0,
                    'month' => 1,
                    'day' => 8,
                    'hour' => 8,
                    'minute' => 0,
                    'second' => 0,
                ],
                'America/Chicago',
                \InvalidArgumentException::class,
            ],
            // Test for invalid month from date array.
[
                [
                    'year' => 2010,
                    'month' => 27,
                    'day' => 8,
                    'hour' => 8,
                    'minute' => 0,
                    'second' => 0,
                ],
                'America/Chicago',
                \InvalidArgumentException::class,
            ],
            // Test for invalid hour from date array.
[
                [
                    'year' => 2010,
                    'month' => 2,
                    'day' => 28,
                    'hour' => 80,
                    'minute' => 0,
                    'second' => 0,
                ],
                'America/Chicago',
                \InvalidArgumentException::class,
            ],
            // Test for invalid minute from date array.
[
                [
                    'year' => 2010,
                    'month' => 7,
                    'day' => 8,
                    'hour' => 8,
                    'minute' => 88,
                    'second' => 0,
                ],
                'America/Chicago',
                \InvalidArgumentException::class,
            ],
            // Regression test for https://www.drupal.org/node/2084455.
[
                [
                    'hour' => 59,
                    'minute' => 1,
                    'second' => 1,
                ],
                'America/Chicago',
                \InvalidArgumentException::class,
            ],
        ];
    }
    
    /**
     * Data provider for testCheckArray.
     *
     * @return array
     *   An array of arrays, each containing:
     *   - 'array' - Input for DateTimePlus::checkArray().
     *   - 'expected' - Expected output for  DateTimePlus::checkArray().
     *
     * @see testCheckArray
     */
    public static function providerTestCheckArray() {
        return [
            'Date array, date only' => [
                [
                    'year' => 2010,
                    'month' => 2,
                    'day' => 28,
                ],
                TRUE,
            ],
            'Date array with hour' => [
                [
                    'year' => 2010,
                    'month' => 2,
                    'day' => 28,
                    'hour' => 10,
                ],
                TRUE,
            ],
            'One year larger than the documented upper limit of checkdate()' => [
                [
                    'year' => 32768,
                    'month' => 1,
                    'day' => 8,
                    'hour' => 8,
                    'minute' => 0,
                    'second' => 0,
                ],
                FALSE,
            ],
            'One year smaller than the documented lower limit of checkdate()' => [
                [
                    'year' => 0,
                    'month' => 1,
                    'day' => 8,
                    'hour' => 8,
                    'minute' => 0,
                    'second' => 0,
                ],
                FALSE,
            ],
            'Invalid month from date array' => [
                [
                    'year' => 2010,
                    'month' => 27,
                    'day' => 8,
                    'hour' => 8,
                    'minute' => 0,
                    'second' => 0,
                ],
                FALSE,
            ],
            'Invalid hour from date array' => [
                [
                    'year' => 2010,
                    'month' => 2,
                    'day' => 28,
                    'hour' => 80,
                    'minute' => 0,
                    'second' => 0,
                ],
                FALSE,
            ],
            'Invalid minute from date array.' => [
                [
                    'year' => 2010,
                    'month' => 7,
                    'day' => 8,
                    'hour' => 8,
                    'minute' => 88,
                    'second' => 0,
                ],
                FALSE,
            ],
            'Missing day' => [
                [
                    'year' => 2059,
                    'month' => 1,
                    'second' => 1,
                ],
                FALSE,
            ],
            'Zero day' => [
                [
                    'year' => 2059,
                    'month' => 1,
                    'day' => 0,
                ],
                FALSE,
            ],
        ];
    }
    
    /**
     * Provides data for testDateTimezone.
     *
     * @return array
     *   An array of arrays, each containing:
     *   - 'date' - Date string or object for DateTimePlus.
     *   - 'timezone' - Timezone string for DateTimePlus.
     *   - 'expected' - Expected return from DateTimePlus::getTimezone()::getName().
     *   - 'message' - Message to display on test failure.
     *
     * @see testDateTimezone
     */
    public static function providerTestDateTimezone() {
        // Use a common date for most of the tests.
        $date_string = '2007-01-31 21:00:00';
        // Detect the system timezone.
        $system_timezone = date_default_timezone_get();
        return [
            // Create a date object with an unspecified timezone, which should
            // end up using the system timezone.
[
                $date_string,
                NULL,
                $system_timezone,
                'DateTimePlus uses the system timezone when there is no site timezone.',
            ],
            // Create a date object with a specified timezone name.
[
                $date_string,
                'America/Yellowknife',
                'America/Yellowknife',
                'DateTimePlus uses the specified timezone if provided.',
            ],
            // Create a date object with a timezone object.
[
                $date_string,
                new \DateTimeZone('Australia/Canberra'),
                'Australia/Canberra',
                'DateTimePlus uses the specified timezone if provided.',
            ],
            // Create a date object with another date object.
[
                new DateTimePlus('now', 'Pacific/Midway'),
                NULL,
                'Pacific/Midway',
                'DateTimePlus uses the specified timezone if provided.',
            ],
        ];
    }
    
    /**
     * Provides data for testTimestamp.
     *
     * @return array
     *   An array of arrays, each containing the arguments required for
     *   self::testTimestamp().
     *
     * @see testTimestamp()
     */
    public static function providerTestTimestamp() {
        return [
            // Create date object from a unix timestamp and display it in
            // local time.
[
                'input' => 0,
                'initial' => [
                    'timezone' => 'UTC',
                    'format' => 'c',
                    'expected_date' => '1970-01-01T00:00:00+00:00',
                    'expected_timezone' => 'UTC',
                    'expected_offset' => 0,
                ],
                'transform' => [
                    'timezone' => 'America/Los_Angeles',
                    'format' => 'c',
                    'expected_date' => '1969-12-31T16:00:00-08:00',
                    'expected_timezone' => 'America/Los_Angeles',
                    'expected_offset' => '-28800',
                ],
            ],
            // Create a date using the timestamp of zero, then display its
            // value both in UTC and the local timezone.
[
                'input' => 0,
                'initial' => [
                    'timezone' => 'America/Los_Angeles',
                    'format' => 'c',
                    'expected_date' => '1969-12-31T16:00:00-08:00',
                    'expected_timezone' => 'America/Los_Angeles',
                    'expected_offset' => '-28800',
                ],
                'transform' => [
                    'timezone' => 'UTC',
                    'format' => 'c',
                    'expected_date' => '1970-01-01T00:00:00+00:00',
                    'expected_timezone' => 'UTC',
                    'expected_offset' => 0,
                ],
            ],
        ];
    }
    
    /**
     * Provides data for testDateTimestamp.
     *
     * @return array
     *   An array of arrays, each containing the arguments required for
     *   self::testDateTimestamp().
     *
     * @see testDateTimestamp()
     */
    public static function providerTestDateTimestamp() {
        return [
            // Create date object from datetime string in UTC, and convert
            // it to a local date.
[
                'input' => '1970-01-01 00:00:00',
                'initial' => [
                    'timezone' => 'UTC',
                    'format' => 'c',
                    'expected_date' => '1970-01-01T00:00:00+00:00',
                    'expected_timezone' => 'UTC',
                    'expected_offset' => 0,
                ],
                'transform' => [
                    'timezone' => 'America/Los_Angeles',
                    'format' => 'c',
                    'expected_date' => '1969-12-31T16:00:00-08:00',
                    'expected_timezone' => 'America/Los_Angeles',
                    'expected_offset' => '-28800',
                ],
            ],
            // Convert the local time to UTC using string input.
[
                'input' => '1969-12-31 16:00:00',
                'initial' => [
                    'timezone' => 'America/Los_Angeles',
                    'format' => 'c',
                    'expected_date' => '1969-12-31T16:00:00-08:00',
                    'expected_timezone' => 'America/Los_Angeles',
                    'expected_offset' => '-28800',
                ],
                'transform' => [
                    'timezone' => 'UTC',
                    'format' => 'c',
                    'expected_date' => '1970-01-01T00:00:00+00:00',
                    'expected_timezone' => 'UTC',
                    'expected_offset' => 0,
                ],
            ],
            // Convert the local time to UTC using string input.
[
                'input' => '1969-12-31 16:00:00',
                'initial' => [
                    'timezone' => 'Europe/Warsaw',
                    'format' => 'c',
                    'expected_date' => '1969-12-31T16:00:00+01:00',
                    'expected_timezone' => 'Europe/Warsaw',
                    'expected_offset' => '+3600',
                ],
                'transform' => [
                    'timezone' => 'UTC',
                    'format' => 'c',
                    'expected_date' => '1969-12-31T15:00:00+00:00',
                    'expected_timezone' => 'UTC',
                    'expected_offset' => 0,
                ],
            ],
        ];
    }
    
    /**
     * Provides data for date tests.
     *
     * @return array
     *   An array of arrays, each containing the input parameters for
     *   DateTimePlusTest::testDateDiff().
     *
     * @see DateTimePlusTest::testDateDiff()
     */
    public static function providerTestDateDiff() {
        $empty_interval = new \DateInterval('PT0S');
        $positive_19_hours = new \DateInterval('PT19H');
        $positive_18_hours = new \DateInterval('PT18H');
        $positive_1_hour = new \DateInterval('PT1H');
        $negative_1_hour = new \DateInterval('PT1H');
        $negative_1_hour->invert = 1;
        return [
            // There should be a 19 hour time interval between
            // new years in Sydney and new years in LA in year 2000.
[
                'input2' => DateTimePlus::createFromFormat('Y-m-d H:i:s', '2000-01-01 00:00:00', new \DateTimeZone('Australia/Sydney')),
                'input1' => DateTimePlus::createFromFormat('Y-m-d H:i:s', '2000-01-01 00:00:00', new \DateTimeZone('America/Los_Angeles')),
                'absolute' => FALSE,
                'expected' => $positive_19_hours,
            ],
            // In 1970 Sydney did not observe daylight savings time
            // So there is only an 18 hour time interval.
[
                'input2' => DateTimePlus::createFromFormat('Y-m-d H:i:s', '1970-01-01 00:00:00', new \DateTimeZone('Australia/Sydney')),
                'input1' => DateTimePlus::createFromFormat('Y-m-d H:i:s', '1970-01-01 00:00:00', new \DateTimeZone('America/Los_Angeles')),
                'absolute' => FALSE,
                'expected' => $positive_18_hours,
            ],
            [
                'input1' => DateTimePlus::createFromFormat('U', '3600', new \DateTimeZone('America/Los_Angeles')),
                'input2' => DateTimePlus::createFromTimestamp(0, new \DateTimeZone('UTC')),
                'absolute' => FALSE,
                'expected' => $negative_1_hour,
            ],
            [
                'input1' => DateTimePlus::createFromTimestamp(3600),
                'input2' => DateTimePlus::createFromTimestamp(0),
                'absolute' => FALSE,
                'expected' => $negative_1_hour,
            ],
            [
                'input1' => DateTimePlus::createFromTimestamp(3600),
                'input2' => \DateTime::createFromFormat('U', '0'),
                'absolute' => FALSE,
                'expected' => $negative_1_hour,
            ],
            [
                'input1' => DateTimePlus::createFromTimestamp(3600),
                'input2' => DateTimePlus::createFromTimestamp(0),
                'absolute' => TRUE,
                'expected' => $positive_1_hour,
            ],
            [
                'input1' => DateTimePlus::createFromTimestamp(3600),
                'input2' => \DateTime::createFromFormat('U', '0'),
                'absolute' => TRUE,
                'expected' => $positive_1_hour,
            ],
            [
                'input1' => DateTimePlus::createFromTimestamp(0),
                'input2' => DateTimePlus::createFromTimestamp(0),
                'absolute' => FALSE,
                'expected' => $empty_interval,
            ],
        ];
    }
    
    /**
     * Provides data for date tests.
     *
     * @return array
     *   An array of arrays, each containing the input parameters for
     *   DateTimePlusTest::testInvalidDateDiff().
     *
     * @see DateTimePlusTest::testInvalidDateDiff()
     */
    public static function providerTestInvalidDateDiff() {
        return [
            [
                'input1' => DateTimePlus::createFromTimestamp(3600),
                'input2' => '1970-01-01 00:00:00',
                'absolute' => FALSE,
            ],
            [
                'input1' => DateTimePlus::createFromTimestamp(3600),
                'input2' => NULL,
                'absolute' => FALSE,
            ],
        ];
    }
    
    /**
     * Tests invalid values passed to constructor.
     *
     * @param string $time
     *   A date/time string.
     * @param string[] $errors
     *   An array of error messages.
     *
     * @covers ::__construct
     *
     * @dataProvider providerTestInvalidConstructor
     */
    public function testInvalidConstructor($time, array $errors) : void {
        $date = new DateTimePlus($time);
        $this->assertEquals(TRUE, $date->hasErrors());
        $this->assertEquals($errors, $date->getErrors());
    }
    
    /**
     * Provider for testInvalidConstructor().
     *
     * @return array
     *   An array of invalid date/time strings, and corresponding error messages.
     */
    public static function providerTestInvalidConstructor() {
        return [
            [
                'YYYY-MM-DD',
                [
                    'The timezone could not be found in the database',
                    'Unexpected character',
                    'Double timezone specification',
                ],
            ],
            [
                '2017-MM-DD',
                [
                    'Unexpected character',
                    'The timezone could not be found in the database',
                ],
            ],
            [
                'YYYY-03-DD',
                [
                    'The timezone could not be found in the database',
                    'Unexpected character',
                    'Double timezone specification',
                ],
            ],
            [
                'YYYY-MM-07',
                [
                    'The timezone could not be found in the database',
                    'Unexpected character',
                    'Double timezone specification',
                ],
            ],
            [
                '2017-13-55',
                [
                    'Unexpected character',
                ],
            ],
            [
                'YYYY-MM-DD hh:mm:ss',
                [
                    'The timezone could not be found in the database',
                    'Unexpected character',
                    'Double timezone specification',
                ],
            ],
            [
                '2017-03-07 25:70:80',
                [
                    'Unexpected character',
                    'Double time specification',
                ],
            ],
            [
                'invalid time string',
                [
                    'The timezone could not be found in the database',
                    'Double timezone specification',
                ],
            ],
        ];
    }
    
    /**
     * Tests the $settings['validate_format'] parameter in ::createFromFormat().
     */
    public function testValidateFormat() : void {
        // Check that an input that does not strictly follow the input format will
        // produce the desired date. In this case the year string '11' doesn't
        // precisely match the 'Y' formatter parameter, but PHP will parse it
        // regardless. However, when formatted with the same string, the year will
        // be output with four digits. With the ['validate_format' => FALSE]
        // $settings, this will not thrown an exception.
        $date = DateTimePlus::createFromFormat('Y-m-d H:i:s', '11-03-31 17:44:00', 'UTC', [
            'validate_format' => FALSE,
        ]);
        $this->assertEquals('0011-03-31 17:44:00', $date->format('Y-m-d H:i:s'));
        // Parse the same date with ['validate_format' => TRUE] and make sure we
        // get the expected exception.
        $this->expectException(\UnexpectedValueException::class);
        $date = DateTimePlus::createFromFormat('Y-m-d H:i:s', '11-03-31 17:44:00', 'UTC', [
            'validate_format' => TRUE,
        ]);
    }
    
    /**
     * Tests setting the default time for date-only objects.
     */
    public function testDefaultDateTime() : void {
        $utc = new \DateTimeZone('UTC');
        $date = DateTimePlus::createFromFormat('Y-m-d H:i:s', '2017-05-23 22:58:00', $utc);
        $this->assertEquals('22:58:00', $date->format('H:i:s'));
        $date->setDefaultDateTime();
        $this->assertEquals('12:00:00', $date->format('H:i:s'));
    }
    
    /**
     * Tests that object methods are chainable.
     *
     * @covers ::__call
     */
    public function testChainable() : void {
        $date = new DateTimePlus('now', 'Australia/Sydney');
        $date->setTimestamp(12345678);
        $rendered = $date->render();
        $this->assertEquals('1970-05-24 07:21:18 Australia/Sydney', $rendered);
        $date->setTimestamp(23456789);
        $rendered = $date->setTimezone(new \DateTimeZone('America/New_York'))
            ->render();
        $this->assertEquals('1970-09-29 07:46:29 America/New_York', $rendered);
        $date = DateTimePlus::createFromFormat('Y-m-d H:i:s', '1970-05-24 07:21:18', new \DateTimeZone('Australia/Sydney'))->setTimezone(new \DateTimeZone('America/New_York'));
        $rendered = $date->render();
        $this->assertInstanceOf(DateTimePlus::class, $date);
        $this->assertEquals(12345678, $date->getTimestamp());
        $this->assertEquals('1970-05-23 17:21:18 America/New_York', $rendered);
    }
    
    /**
     * Tests that non-chainable methods work.
     *
     * @covers ::__call
     */
    public function testChainableNonChainable() : void {
        $datetime1 = new DateTimePlus('2009-10-11 12:00:00');
        $datetime2 = new DateTimePlus('2009-10-13 12:00:00');
        $interval = $datetime1->diff($datetime2);
        $this->assertInstanceOf(\DateInterval::class, $interval);
        $this->assertEquals('+2 days', $interval->format('%R%a days'));
    }
    
    /**
     * Tests that chained calls to non-existent functions throw an exception.
     *
     * @covers ::__call
     */
    public function testChainableNonCallable() : void {
        $this->expectException(\BadMethodCallException::class);
        $this->expectExceptionMessage('Call to undefined method Drupal\\Component\\Datetime\\DateTimePlus::nonexistent()');
        $date = new DateTimePlus('now', 'Australia/Sydney');
        $date->setTimezone(new \DateTimeZone('America/New_York'))
            ->nonexistent();
    }
    
    /**
     * @covers ::getPhpDateTime
     */
    public function testGetPhpDateTime() : void {
        $new_york = new \DateTimeZone('America/New_York');
        $berlin = new \DateTimeZone('Europe/Berlin');
        // Test retrieving a cloned copy of the wrapped \DateTime object, and that
        // altering it does not change the DateTimePlus object.
        $datetimeplus = DateTimePlus::createFromFormat('Y-m-d H:i:s', '2017-07-13 22:40:00', $new_york, [
            'langcode' => 'en',
        ]);
        $this->assertEquals(1500000000, $datetimeplus->getTimestamp());
        $this->assertEquals('America/New_York', $datetimeplus->getTimezone()
            ->getName());
        $datetime = $datetimeplus->getPhpDateTime();
        $this->assertInstanceOf('DateTime', $datetime);
        $this->assertEquals(1500000000, $datetime->getTimestamp());
        $this->assertEquals('America/New_York', $datetime->getTimezone()
            ->getName());
        $datetime->setTimestamp(1400000000)
            ->setTimezone($berlin);
        $this->assertEquals(1400000000, $datetime->getTimestamp());
        $this->assertEquals('Europe/Berlin', $datetime->getTimezone()
            ->getName());
        $this->assertEquals(1500000000, $datetimeplus->getTimestamp());
        $this->assertEquals('America/New_York', $datetimeplus->getTimezone()
            ->getName());
    }

}