The ansi_x3.4_1968 encoding is an alias for ascii, but isn't known in

Python 2.1.3.  However it's required by the email tests suite, so poke
it into the encodings aliases if it's missing.  The is apparently the
approved API for doing so.

Now we can remove the hexversion shortcircuits in the test suite.

Lib/email/__init__.py

@@ -59,3 +59,12 @@ def message_from_file(fp, _class=None, strict=False):
         from email.Message import Message
         _class = Message
     return Parser(_class, strict=strict).parse(fp)
+
+
+
+# Patch encodings.aliases to recognize 'ansi_x3.4_1968' which isn't a standard
+# alias in Python 2.1.3, but is used by the email package test suite.
+from encodings.aliases import aliases # The aliases dictionary
+if not aliases.has_key('ansi_x3.4_1968'):
+    aliases['ansi_x3.4_1968'] = 'ascii'
+del aliases # Not needed any more

Lib/email/test/test_email.py

@@ -1470,12 +1470,6 @@ class TestIdempotent(TestEmailBase):
         self._idempotent(msg, text)
 
     def test_more_rfc2231_parameters(self):
-        # BAW: What to do about this.  Python 2.1 doesn't know about the
-        # charset ansi-x3.4-1968, so this test will fail.  Do we teach Python
-        # about that charset, and if so, where (maybe Charset.py)?  For now,
-        # just skip this test if we aren't at least in Python 2.2.
-        if sys.hexversion < 0x20200000:
-            return
         msg, text = self._msgobj('msg_33.txt')
         self._idempotent(msg, text)
 
@@ -2258,12 +2252,6 @@ Do you like this message?
 """)
 
     def test_rfc2231_get_content_charset(self):
-        # BAW: What to do about this.  Python 2.1 doesn't know about the
-        # charset ansi-x3.4-1968, so this test will fail.  Do we teach Python
-        # about that charset, and if so, where (maybe Charset.py)?  For now,
-        # just skip this test if we aren't at least in Python 2.2.
-        if sys.hexversion < 0x20200000:
-            return
         eq = self.assertEqual
         msg = self._msgobj('msg_32.txt')
         eq(msg.get_content_charset(), 'us-ascii')