public function testColumns()
{
$collection = TestUtil::createCollection([[]]);
$report = $this->generate($collection, ['cols' => ['mean', 'mode', 'benchmark', 'subject']]);
$this->assertXPathCount($report, 4, '//cell');
$this->assertXPathCount($report, 0, '//cell[@name="mean"]/preceding-sibling::cell');
$this->assertXPathCount($report, 1, '//cell[@name="mode"]/preceding-sibling::cell');
$this->assertXPathCount($report, 2, '//cell[@name="benchmark"]/preceding-sibling::cell');
$this->assertXPathCount($report, 3, '//cell[@name="subject"]/preceding-sibling::cell');
}