Supporting empty path elements seems a lost use case, as explained

in http://mail.zope.org/pipermail/zope-dev/2006-May/027493.html.
Disable the corresponding tests therefore.

lib/python/Products/PageTemplates/tests/testExpressions.py

@@ -50,26 +50,11 @@ class ExpressionTests(unittest.TestCase):
         '''Test advanced expression evaluation 1'''
         ec = self.ec
         assert ec.evaluate('x | nothing') is None
-
-        # XXX The following test fails because Zope 3 doesn't allow
-        # empty path elements.  My idea is to eventually disallow
-        # blank path elements, but to allow them for a limited
-        # deprecation period.  We do that by implementing our own
-        # SubPathExpr that just looks for empty path elements and
-        # replaces them with a call to a TALESNamespace adapter that
-        # explicitly does the empty element lookup.  Then we hand off
-        # to the standard Zope 3 SubPathExpr implementation.
-        # Something along these lines (pseudo-ish code!):
-        #
-        # class Zope2SubPathExpr(SubPathExpr):
-        #     def __init__(self, text, ...):
-        #         text = text.replace('//', 'blank:element')
-        #         return super(Zope2SubPathExpr, self).__init__(text ...)
-        #
-        assert ec.evaluate('d/') == 'blank'
-
+        # empty path elements aren't supported anymore, for the lack
+        # of a use case
+        #assert ec.evaluate('d/') == 'blank'
         assert ec.evaluate('d/_') == 'under'
-        assert ec.evaluate('d/ | nothing') == 'blank'
+        #assert ec.evaluate('d/ | nothing') == 'blank'
         assert ec.evaluate('d/?blank') == 'blank'
 
     def testHybrid(self):