The 'check_seasons' function now raises a 'ValueError' if there is any problem...

The 'check_seasons' function now raises a 'ValueError' if there is any problem with the given 'seasons' argument.

toarstats/input_checks.py

@@ -242,28 +242,41 @@ def check_metadata(metadata_in, station_lat_in, station_lon_in,
     return namedtuple("Metadata", metadata_dict)(**metadata_dict)
 
 
-def check_seasons(seasons_in):
+def check_seasons(seasons_in, seasons_req):
     """Check the given seasons argument.
 
     :param seasons_in: the given seasons argument
+    :param seasons_req: boolean denoting whether the seasons argument is
+                        required
 
-    :return: The processed seasons argument or None if there was a
-             problem while processing the given seasons argument
+    :raises ValueError: raised if the seasons argument is required and
+                        either missing or is not a type of list or a
+                        string or if no season is given or if any given
+                        season is not recognized
+
+    :return: A list of seasons or None if the seasons argument is not
+             needed
     """
-    if not isinstance(seasons_in, (list, str)):
+    if not seasons_req:
         return None
-    seasons_in_list = (
-        [seasons_in] if isinstance(seasons_in, str) else seasons_in
-    )
+    if not isinstance(seasons_in, (list, set, tuple, str)):
+        raise ValueError("The seasons argument must be a list, set, tuple or"
+                         " string")
+    if not seasons_in:
+        raise ValueError("No seasons given")
+    seasons_in_list = ([seasons_in] if isinstance(seasons_in, str)
+                       else list(seasons_in))
     seasons_out = []
     for season in seasons_in_list:
         if not isinstance(season, str):
-            continue
+            raise ValueError("Seasons must be given as strings")
         season = season.strip()
-        if season in SEASON_DICT and season not in seasons_out:
+        if season in seasons_out:
+            continue
+        if season in SEASON_DICT:
             seasons_out.append(season)
-    if not seasons_out:
-        return None
+        else:
+            raise ValueError(f"{season} is not a recognized season")
     return seasons_out
 
 

toarstats/interface.py

@@ -110,6 +110,6 @@ def calculate_statistics(
         metadata, station_lat, station_lon, station_climatic_zone,
         station_lat_req, station_lon_req, station_climatic_zone_req
     )
-    seasons_list = check_seasons(seasons)
+    seasons_list = check_seasons(seasons, seasons_req)
     crops_list = check_crops(crops)
     data_capture_value = check_data_capture(data_capture)