Updated test with a case which checks for the bug reported in
diff --git a/Lib/test/test_unicode.py b/Lib/test/test_unicode.py
index 8479c20..0c44fbf 100644
--- a/Lib/test/test_unicode.py
+++ b/Lib/test/test_unicode.py
@@ -341,6 +341,7 @@
assert '...%(foo)s...' % {u'foo':u"abc",'def':123} == u'...abc...'
assert '...%(foo)s...' % {u'foo':u"abc",u'def':123} == u'...abc...'
assert '...%s...%s...%s...%s...' % (1,2,3,u"abc") == u'...1...2...3...abc...'
+assert '...%%...%%s...%s...%s...%s...%s...' % (1,2,3,u"abc") == u'...%...%s...1...2...3...abc...'
assert '...%s...' % u"abc" == u'...abc...'
print 'done.'