public void test_assertArgumentExists() throws Exception {
    String[] twoArgs = new String[] {"-logfile", "c:/tmp"};
    CommandLineArguments arguments = new CommandLineArguments(twoArgs);

    arguments.assertArgumentExists("logfile");

    try {
      arguments.assertArgumentExists("unknwonArg");
      fail();
    } catch (IllegalArgumentException ex) {
      assertEquals("L'argument obligatoire 'unknwonArg' est absent.", ex.getMessage());
    }
  }