Minor update to tests, added docstrings

Requested by @sigmavirus24.

test_requests.py

@@ -460,7 +460,11 @@ def test_session_pickling(self):
  self.assertEqual(r.status_code, 200)
 
  def test_fixes_1329(self):
+ """
+ Ensure that header updates are done case-insensitively.
+ """
  s = requests.Session()
+ s.headers.update({'ACCEPT': 'BOGUS'})
  s.headers.update({'accept': 'application/json'})
  r = s.get(httpbin('get'))
  headers = r.request.headers
@@ -473,6 +477,10 @@ def test_fixes_1329(self):
  headers['Accept'.encode('ascii')],
  'application/json'
  )
+ self.assertEqual(
+ headers['ACCEPT'.encode('ascii')],
+ 'application/json'
+ )
 
 
 class TestCaseInsensitiveDict(unittest.TestCase):
@@ -512,6 +520,7 @@ def test_getitem(self):
  self.assertEqual(cid['SPAM'], 'blueval')
 
  def test_fixes_649(self):
+ """__setitem__ should behave case-insensitively."""
  cid = CaseInsensitiveDict()
  cid['spam'] = 'oneval'
  cid['Spam'] = 'twoval'