Convert BaseAuthenticator, BaseAuthorizer, and RetryStrategy to abstr…

…act classes

(cherry picked from commit praw-dev/prawcore@73dd4c9)

asyncprawcore/auth.py

@@ -1,6 +1,7 @@
 """Provides Authentication and Authorization classes."""
 import inspect
 import time
+from abc import ABC, abstractmethod
 from typing import (
     TYPE_CHECKING,
     Awaitable,
@@ -25,7 +26,7 @@
     from asyncprawcore.requestor import Requestor
 
 
-class BaseAuthenticator(object):
+class BaseAuthenticator(ABC):
     """Provide the base authenticator object that stores OAuth2 credentials."""
 
     def __init__(
@@ -46,6 +47,10 @@ def __init__(
         self.client_id = client_id
         self.redirect_uri = redirect_uri
 
+    @abstractmethod
+    def _auth(self):
+        pass
+
     async def _post(
         self, url: str, success_status: int = codes["ok"], **data
     ) -> ClientResponse:
@@ -164,7 +169,7 @@ def _auth(self) -> BasicAuth:
         return BasicAuth(self.client_id, "")
 
 
-class BaseAuthorizer(object):
+class BaseAuthorizer(ABC):
     """Superclass for OAuth2 authorization tokens and scopes."""
 
     AUTHENTICATOR_CLASS: Union[Tuple, Type] = BaseAuthenticator

asyncprawcore/sessions.py

@@ -2,6 +2,7 @@
 import asyncio
 import logging
 import random
+from abc import ABC, abstractmethod
 from copy import deepcopy
 from typing import TYPE_CHECKING, Any, Dict, List, Optional, Tuple, Union
 from urllib.parse import urljoin
@@ -41,14 +42,17 @@
 log = logging.getLogger(__package__)
 
 
-class RetryStrategy(object):
+class RetryStrategy(ABC):
     """An abstract class for scheduling request retries.
 
     The strategy controls both the number and frequency of retry attempts.
 
     Instances of this class are immutable.
 
     """
+    @abstractmethod
+    def _sleep_seconds(self) -> Optional[float]:
+        pass
 
     async def sleep(self) -> None:
         """Sleep until we are ready to attempt the request."""

tests/unit/test_authorizer.py

@@ -16,6 +16,11 @@ async def setUp(self):
         )
 
 
+class InvalidAuthenticator(asyncprawcore.auth.BaseAuthenticator):
+    def _auth(self):
+        pass
+
+
 class TestAuthorizer(AuthorizerBase):
     async def test_authorize__fail_without_redirect_uri(self):
         authorizer = asyncprawcore.Authorizer(self.authentication)
@@ -79,10 +84,8 @@ def test_initialize(self):
         assert authorizer.scopes is None
         assert not authorizer.is_valid()
 
-    def test_initialize__with_base_authenticator(self):
-        authenticator = asyncprawcore.Authorizer(
-            asyncprawcore.auth.BaseAuthenticator(None, None, None)
-        )
+    def test_initialize__with_invalid_authenticator(self):
+        authenticator = asyncprawcore.Authorizer(InvalidAuthenticator(None, None, None))
         with pytest.raises(asyncprawcore.InvalidInvocation):
             asyncprawcore.DeviceIDAuthorizer(
                 authenticator,