Testing

• LoanPeriod -- change
• Media -- creation, change, deletion (-- wahrscheinlich reicht es das fuer einen Medientypen zu machen)
• LendMediaController
  • lend different media in different circumstances:
    • - inexistent media to inexistent user
    • - unavailable media
    • - once #25 (closed) is fixed, loan media for 1 sec, sleep 2 sec, check that it's back
  • return media in different circumstances:
    • - return LentMedia that's not actually lent out
    • - return LentMedia where availability was 0 -- check that it tries to notify users