Linting of core subpackage + clean up imports (#437)

* Linting of OAuth2 mod. + update tests to detect core package path

* Tweak imports in tests + update tox ini to ignore Flake8 E501 error

* Tweak tox ini - ignore examples

* Remove `f`-string from OAuth2 mod.

* More import tweaks in core package + tests

* Update flake8 config. in tox ini - set line length limit to 99 chars.

spotipy/client.py

@@ -12,10 +12,10 @@ __all__ = [
 import json
 import sys
 import time
+import warnings
 
 import requests
 import six
-import warnings
 
 
 class SpotifyException(Exception):

spotipy/oauth2.py

@@ -29,9 +29,8 @@ class SpotifyOauthError(Exception):
 def _make_authorization_headers(client_id, client_secret):
     auth_header = base64.b64encode(
         six.text_type(
-            client_id +
-            ':' +
-            client_secret).encode('ascii'))
+            '{}:{}'.format(client_id, client_secret)
+        ).encode('ascii'))
     return {'Authorization': 'Basic %s' % auth_header.decode('ascii')}
 
 

tests/integration/test_non_user_endpoints.py

@@ -219,8 +219,7 @@ class AuthTestSpotipy(unittest.TestCase):
         with self.assertRaises(SpotifyException) as cm:
             self.spotify.user_playlist_create(
                 "spotify", "Best hits of the 90s")
-        self.assertTrue(cm.exception.http_status == 401 or
-                        cm.exception.http_status == 403)
+        self.assertTrue(cm.exception.http_status == 401 or cm.exception.http_status == 403)
 
     def test_custom_requests_session(self):
         sess = requests.Session()

tests/integration/test_user_endpoints.py

@@ -11,17 +11,17 @@ following environment variables
     'SPOTIPY_CLIENT_SECRET'
     'SPOTIPY_REDIRECT_URI'
 """
-
 from __future__ import print_function
 
+import os
+import sys
+
 from spotipy import (
     CLIENT_CREDS_ENV_VARS as CCEV,
     prompt_for_user_token,
     Spotify,
     SpotifyException,
 )
-import os
-import sys
 import unittest
 import warnings
 import requests

tests/unit/test_oauth.py

@@ -1,11 +1,11 @@
 # -*- coding: utf-8 -*-
-
-import six.moves.urllib.parse as urllibparse
-from spotipy import SpotifyOAuth
 import io
 import json
 import unittest
 
+import six.moves.urllib.parse as urllibparse
+
+from spotipy import SpotifyOAuth
 
 try:
     import unittest.mock as mock

tox.ini

@@ -7,7 +7,9 @@ deps=
     py27: mock
 commands=python -m unittest discover -v tests
 [flake8]
+max-line-length = 99
 exclude=
     .git,
     dist,
-    docs
+    docs,
+    examples