- var_dump: documentation ( source)
<?php
$tz = new DateTimeZone('Europe/London');
$date = new DateTimeImmutable('now', $tz);
$time = 1509235200;
$date1 = $date->setTimestamp($time - 1);
$date2 = $date->setTimestamp($time);
$date3 = $date->setTimestamp($time + 3600 - 1);
$date4 = $date->setTimestamp($time + 3600);
$date5 = $date->setTimestamp($time + 3600*2 - 1);
var_dump($date1->format(DateTime::ATOM));
var_dump($date2->format(DateTime::ATOM));
var_dump($date3->format(DateTime::ATOM));
var_dump($date4->format(DateTime::ATOM));
var_dump($date5->format(DateTime::ATOM));