Not sure if being able to understand the lyrics of an NTM or Stromae song should be testable, but I see the point. French is especially bitchy in that respect since what you learn as formal language will leave out a HUGE part of words and idioms used in everyday interactions. You can speak perfect French but sound like you just stepped out of a time machine. “C’est pas terrible” (colloquial) instead of “Ce n’est pas très bon” (more grammatically correct). “T’inquiètes!” vs “Ne t’inquiètes pas”