public function testInvalidHeader()
{
/** @var Filesystem|\PHPUnit_Framework_MockObject_MockObject $filesystem */
$filesystem = $this->getMock('Symfony\\Component\\Filesystem\\Filesystem');
/** @var PhpFileLoader|\PHPUnit_Framework_MockObject_MockObject $fileLoader */
$fileLoader = $this->getMock('Contao\\CoreBundle\\Config\\Loader\\PhpFileLoader');
$dumper = new CombinedFileDumper($filesystem, $fileLoader, $this->getCacheDir());
$dumper->setHeader('No opening PHP tag');
}