public function checkFilePresence($paths, $expectPresence)
    {
        $this->inCurrentDir(function() use ($paths, $expectPresence) {
            foreach((array) $paths as $file) {
                $present = file_exists($file);

                if ($expectPresence && !$present) {
                    throw new ExpectationException("Could not find file:$file");
                }

                if ($present && !$expectPresence) {
                    throw new ExpectationException("Found unexpected file:$file");
                }
            }
        });
    }