Adding test to ensure options like stream function with authentication

This test demonstrates the reason why we need to pass kwargs to hooks. Without
it, features like stream cannot work with authentication.

test_requests.py

@@ -172,6 +172,18 @@ class RequestsTestCase(unittest.TestCase):
         r = s.get(url)
         self.assertEqual(r.status_code, 200)
 
+    def test_DIGEST_STREAM(self):
+
+        auth = HTTPDigestAuth('user', 'pass')
+        url = httpbin('digest-auth', 'auth', 'user', 'pass')
+
+        r = requests.get(url, auth=auth, stream=True)
+        self.assertNotEqual(r.raw.read(), '')
+
+        r = requests.get(url, auth=auth, stream=False)
+        self.assertEqual(r.raw.read(), '')
+
+
     def test_DIGESTAUTH_WRONG_HTTP_401_GET(self):
 
         auth = HTTPDigestAuth('user', 'wrongpass')