even more tests!

src/rest/mod.rs

@@ -72,6 +72,9 @@ async fn join(db: &State<SqlitePool>, trip_details_id: i64, user: User) -> Flash
         Err(UserTripError::AlreadyRegisteredAsCox) => {
             Flash::error(Redirect::to("/"), "Du hilfst bereits als Steuerperson aus!")
         }
+        Err(UserTripError::TripDetailsNotFound) => {
+            Flash::error(Redirect::to("/"), "Trip_details do not exist.")
+        }
     }
 }