chore: better errors reporting

wumpus/runner.py

@@ -7,6 +7,7 @@ Functions to run the players
 import argparse
 import copy
 import importlib
+import inspect
 import io
 import json
 import os
@@ -51,17 +52,20 @@ def get_player_class(object_ref: str, path: os.PathLike = None) -> Union[Type[On
 
     # see <https://packaging.python.org/specifications/entry-points/#data-model>
     modname, qualname_separator, qualname = object_ref.partition(':')
-    obj = importlib.import_module(modname)
+    try:
+        obj = importlib.import_module(modname)
+    except ModuleNotFoundError as e:
+        raise ImportError(f'Cannot find entrypoint {object_ref}: {e}')
     if qualname_separator:
         for attr in qualname.split('.'):
             try:
                 obj = getattr(obj, attr)
             except AttributeError as e:
-                raise ImportError('Cannot import {} object: {}'.format(object_ref, e))
+                raise ImportError(f'Cannot find entrypoint {object_ref}: {e}')
 
     player_class = obj
-    if not issubclass(player_class, (OnlinePlayer, OfflinePlayer)):
-        raise NotImplementedError('class {} is not a player class'.format(player_class))
+    if not inspect.isclass(player_class) or not issubclass(player_class, (OnlinePlayer, OfflinePlayer)):
+        raise RuntimeError(f'{player_class} is not a subclass of OnlinePlayer or OfflinePlayer')
     return player_class