Description:
------------
var_dump(test('2019-10-27 08:55:00'));//result is 2019-10-27 02:55:00
var_dump(test('2019-10-27 09:55:00'));//result is also 2019-10-27 02:55:00

It`s incorrect.

Test script:
---------------
<?php
ini_set('date.timezone', 'Asia/Shanghai');

var_dump(test('2019-10-27 08:55:00'));//result is 2019-10-27 02:55:00
var_dump(test('2019-10-27 09:55:00'));//result is also 2019-10-27 02:55:00

function test($testDate)
{
    $format = 'Y-m-d H:i:s';
    $timezone = 'Europe/Paris';
    // if ($timezone == 'Europe/Paris') {
    //     return date($format, strtotime($testDate) - 7 * 3600);
    // }
    $date = new DateTime($testDate);
    $date->setTimezone(new DateTimeZone($timezone));
    return $date->format($format);
}


Expected result:
----------------
var_dump(test('2019-10-27 08:55:00'));//result is 2019-10-27 01:55:00
var_dump(test('2019-10-27 09:55:00'));//result is also 2019-10-27 02:55:00

It`s correct.

Actual result:
--------------
var_dump(test('2019-10-27 08:55:00'));//result is 2019-10-27 02:55:00
var_dump(test('2019-10-27 09:55:00'));//result is also 2019-10-27 02:55:00

It`s incorrect.