Add regression test for a bug found in the version of the markupbase

module used in the Zope TAL implementation.  The bug was already fixed
in the Python standard library, but the regression test would be good
to keep around.

Lib/test/test_sgmllib.py

@@ -262,6 +262,12 @@ DOCTYPE html PUBLIC '-//W3C//DTD HTML 4.01//EN'
             ("data", "def"),
             ])
 
+    def test_enumerated_attr_type(self):
+        s = "<!DOCTYPE doc [<!ATTLIST doc attr (a | b) >]>"
+        self.check_events(s, [
+            ('decl', 'DOCTYPE doc [<!ATTLIST doc attr (a | b) >]'),
+            ])
+
     # XXX These tests have been disabled by prefixing their names with
     # an underscore.  The first two exercise outstanding bugs in the
     # sgmllib module, and the third exhibits questionable behavior