public function testGetPeriods() {
$event = new StopwatchEvent(microtime(true) * 1000);
$this
->assertEquals(array(), $event
->getPeriods());
$event = new StopwatchEvent(microtime(true) * 1000);
$event
->start();
$event
->stop();
$this
->assertCount(1, $event
->getPeriods());
$event = new StopwatchEvent(microtime(true) * 1000);
$event
->start();
$event
->stop();
$event
->start();
$event
->stop();
$this
->assertCount(2, $event
->getPeriods());
}