- In order to test the "/contract" facility of the merchant,
  just issue

  - curl http://merchant-url/generate_taler_contract.php?cli_debug=yes
    (this form tests the whole communication between frontend and backend)

  - curl http://merchant-url/generate_taler_contract.php?backend_test=no
    (this form test only the contract proposition generation of the frontend,
     so it doesn't further connect to the backend to get the proposition JSON
     enhanced)