From f4748cc2a7e57d05774ab440e2fdbb7444d6b29c Mon Sep 17 00:00:00 2001
From: Diogo Baeder de Paula Pinto <diogobaeder@yahoo.com.br>
Date: Fri, 18 Dec 2015 18:52:15 -0200
Subject: [PATCH] Cleaning the previous token before fetching a new one, to
 avoid a TokenExpiredError

---
 requests_oauthlib/oauth2_session.py |  1 +
 tests/test_oauth2_session.py        | 37 ++++++++++++++++++++++++-----
 2 files changed, 32 insertions(+), 6 deletions(-)

diff --git a/requests_oauthlib/oauth2_session.py b/requests_oauthlib/oauth2_session.py
index 05bc24d5..9aa2e02b 100644
--- a/requests_oauthlib/oauth2_session.py
+++ b/requests_oauthlib/oauth2_session.py
@@ -206,6 +206,7 @@ def fetch_token(self, token_url, code=None, authorization_response=None,
             'Accept': 'application/json',
             'Content-Type': 'application/x-www-form-urlencoded;charset=UTF-8',
         }
+        self.token = {}
         if method.upper() == 'POST':
             r = self.post(token_url, data=dict(urldecode(body)),
                 timeout=timeout, headers=headers, auth=auth,
diff --git a/tests/test_oauth2_session.py b/tests/test_oauth2_session.py
index 3547de1e..bb5201e9 100644
--- a/tests/test_oauth2_session.py
+++ b/tests/test_oauth2_session.py
@@ -2,6 +2,7 @@
 import json
 import mock
 import time
+from copy import deepcopy
 try:
     from unittest2 import TestCase
 except ImportError:
@@ -18,6 +19,15 @@
 fake_time = time.time()
 
 
+
+def fake_token(token):
+    def fake_send(r, **kwargs):
+        resp = mock.MagicMock()
+        resp.text = json.dumps(token)
+        return resp
+    return fake_send
+
+
 class OAuth2SessionTest(TestCase):
 
     def setUp(self):
@@ -117,12 +127,6 @@ def test_token_from_fragment(self):
 
     @mock.patch("time.time", new=lambda: fake_time)
     def test_fetch_token(self):
-        def fake_token(token):
-            def fake_send(r, **kwargs):
-                resp = mock.MagicMock()
-                resp.text = json.dumps(token)
-                return resp
-            return fake_send
         url = 'https://example.com/token'
 
         for client in self.clients:
@@ -136,6 +140,27 @@ def fake_send(r, **kwargs):
             auth.send = fake_token(error)
             self.assertRaises(OAuth2Error, auth.fetch_token, url)
 
+    def test_cleans_previous_token_before_fetching_new_one(self):
+        """Makes sure the previous token is cleaned before fetching a new one.
+
+        The reason behind it is that, if the previous token is expired, this
+        method shouldn't fail with a TokenExpiredError, since it's attempting
+        to get a new one (which shouldn't be expired).
+
+        """
+        new_token = deepcopy(self.token)
+        past = time.time() - 7200
+        now = time.time()
+        self.token['expires_at'] = past
+        new_token['expires_at'] = now + 3600
+        url = 'https://example.com/token'
+
+        with mock.patch('time.time', lambda: now):
+            for client in self.clients:
+                auth = OAuth2Session(client=client, token=self.token)
+                auth.send = fake_token(new_token)
+                self.assertEqual(auth.fetch_token(url), new_token)
+
 
     def test_web_app_fetch_token(self):
         # Ensure the state parameter is used, see issue #105.