introduced test if all requested variables are available, the join module will...

introduced test if all requested variables are available, the join module will raise an EmptyQueryResult with detailed information which variables could not be loaded

mlair/helpers/join.py

@@ -47,6 +47,13 @@ def download_join(station_name: Union[str, List[str]], stat_var: dict, station_t
     # load series information
     vars_dict = load_series_information(station_name, station_type, network_name, join_url_base, headers, data_origin)
 
+    # check if all requested variables are available
+    if set(stat_var).issubset(vars_dict) is False:
+        missing_variables = set(stat_var).difference(vars_dict)
+        origin = helpers.select_from_dict(data_origin, missing_variables)
+        options = f"station={station_name}, type={station_type}, network={network_name}, origin={origin}"
+        raise EmptyQueryResult(f"No data found for variables {missing_variables} and options {options} in JOIN.")
+
     # correct stat_var values if data is not aggregated (hourly)
     if sampling == "hourly":
         stat_var = {key: "values" for key in stat_var.keys()}