public function testZeroTime()
{
$collection = TestUtil::createCollection([['basetime' => 0, 'iterations' => [0]]]);
$report = $this->generate($collection);
$this->assertXPathEval($report, '0', 'string(//cell[@name="diff"])');
$this->assertXPathEval($report, '0', 'string(//cell[@name="mean"])');
}