DateTimeTest.php

<?php

class DateTimeTest extends PHPUnit_Framework_TestCase
{
    private $dateTimeZone;

    public function setUp()
    {
        $this->dateTimeZone = new DateTimeZone("UTC");
    }

    public function tearDown()
    {
        $this->dateTimeZone = null;
    }

    public function testCreateDateTimeForNowWithMilliSeconds()
    {
        $microtime = sprintf('%.f', microtime(true));
        $composed = DateTime::createFromFormat('U.u', $microtime, $this->dateTimeZone);
        $expected = new DateTime('now', $this->dateTimeZone);

        foreach (array('Y', 'm', 'd', 'H', 'i', 's') as $modifier) {
            $this->assertEquals($expected->format($modifier), $composed->format($modifier));
        }

        $this->assertEquals($composed->format('U.u'), $microtime);
    }
}