public function testCanUseXvfbRun()
{
$inFile = $this->getHtmlAsset();
$outFile = $this->getOutFile();
$binary = $this->getBinary();
$pdf = new Pdf(array('binary' => $binary, 'commandOptions' => array('enableXvfb' => true)));
$this->assertInstanceOf('mikehaertl\\wkhtmlto\\Pdf', $pdf->addPage($inFile));
$this->assertTrue($pdf->saveAs($outFile));
$tmpFile = $pdf->getPdfFilename();
$this->assertEquals("xvfb-run -a --server-args=\"-screen 0, 1024x768x24\" {$binary} '{$inFile}' '{$tmpFile}'", (string) $pdf->getCommand());
unlink($outFile);
}