/**
  * @expectedException \InvalidArgumentException
  */
 public function testInvalid()
 {
     JSONHelper::format('{invalidKey: false}');
 }
 /**
  * Saves the json object back to the composer file.
  * 
  * @param object $json
  * @return string the serialized content
  */
 private function save($json)
 {
     $serialized = JSONHelper::format(json_encode($json));
     $fixed = str_replace('"_empty_":', '"":', $serialized);
     file_put_contents($this->composerFile, $fixed);
     return $serialized;
 }