Index: Lib/test/test_urllib2.py
===================================================================
--- Lib/test/test_urllib2.py	(revision 67015)
+++ Lib/test/test_urllib2.py	(working copy)
@@ -47,6 +47,56 @@
             self.assertEquals(urllib2.parse_http_list(string), list)
 
 
+def test_case_insensitive_dict():
+    """
+    Original key case is preserved
+
+    >>> sorted(urllib2.CaseInsensitiveDict(spam="eggs", Eggs="spam").items())
+    [('Eggs', 'spam'), ('spam', 'eggs')]
+
+    Lookup is case-insensitive
+
+    >>> urllib2.CaseInsensitiveDict(spam="eggs")["SPAM"]
+    'eggs'
+
+    The most recently set item for each case-canonicalized key is returned on
+    key lookup
+
+    >>> r = urllib2.CaseInsensitiveDict(spam="eggs")
+    >>> r["SPAM"] = "spam"
+    >>> r["spam"]
+    'spam'
+
+    but all of the items that were set still remain (jlee: I think this is pretty confusing behaviour)
+
+    >>> sorted(r.items())
+    [('SPAM', 'spam'), ('spam', 'eggs')]
+
+    Inherited methods preserve invariants
+
+    >>> r = urllib2.CaseInsensitiveDict(spam="eggs")
+    >>> r["spam"] = "eggs"
+    >>> r["SPAM"] = "spam"
+    >>> del r['SPAM']
+    >>> r.items()
+    [('spam', 'eggs')]
+    >>> 'spam' in r
+    True
+
+    >>> r = urllib2.CaseInsensitiveDict(spam="eggs")
+    >>> r.update({'SPAM': 'spam'})
+    >>> r['spam']
+    'spam'
+
+    Non-string keys are not allowed
+
+    >>> r = urllib2.CaseInsensitiveDict({None: 'spam'})
+    Traceback (most recent call last):
+    TypeError
+
+    """
+
+
 def test_request_headers_dict():
     """
     The Request.headers dictionary is not a documented interface.  It should