Merge pull request #4 from das7pad/bugfix/ensure-non-abstract-engine

[shorteners] fix check for implemented `short`/`extend` methods

aiourlshortener/shorteners/__init__.py

@@ -15,7 +15,7 @@
  _shorten = SourceFileLoader('aiourlshortener.shorteners.', '{}/{}'.format(_path, file)).load_module()
  for attr in dir(_shorten):
  tmp_cls = getattr(_shorten, attr)
- if inspect.isclass(tmp_cls) and attr != 'BaseShortener' and issubclass(tmp_cls, BaseShortener):
+ if attr != 'BaseShortener' and inspect.isclass(tmp_cls) and issubclass(tmp_cls, BaseShortener) and not inspect.isabstract(tmp_cls):
  _shorten_class[attr] = tmp_cls
 
 __all__ = ['Shorteners', 'Shortener']
@@ -36,7 +36,7 @@ def __init__(self, engine, **kwargs):
  self.shorten = None
  self.expanded = None
 
- if inspect.isclass(engine) and issubclass(engine, BaseShortener):
+ if inspect.isclass(engine) and issubclass(engine, BaseShortener) and not inspect.isabstract(engine):
  self.engine = engine.__name__
  self._class = engine
  elif engine in _shorten_class:

aiourlshortener/shorteners/base.py

@@ -1,12 +1,12 @@
+from abc import abstractmethod, ABC
 import asyncio
-from abc import abstractmethod
 import aiohttp
 from asyncio import coroutine
 
 from ..exceptions import FetchError
 
 
-class BaseShortener(object):
+class BaseShortener(ABC):
  """
  Base class for all Shorteners
  """