Fixed #17492 -- Allow reversal of named backreferences. Thanks nate_b

git-svn-id: http://code.djangoproject.com/svn/django/trunk@17336 bcc190cf-cafb-0310-a4f2-bffc1f526a37

tests/regressiontests/utils/regex_helper.py

@@ -0,0 +1,48 @@
+from django.utils import regex_helper
+from django.utils import unittest
+
+
+class NormalizeTests(unittest.TestCase):
+    def test_empty(self):
+        pattern = r""
+        expected = [(u'', [])]
+        result = regex_helper.normalize(pattern)
+        self.assertEqual(result, expected)
+
+    def test_escape(self):
+        pattern = r"\\\^\$\.\|\?\*\+\(\)\["
+        expected = [(u'\\^$.|?*+()[', [])]
+        result = regex_helper.normalize(pattern)
+        self.assertEqual(result, expected)
+
+    def test_group_positional(self):
+        pattern = r"(.*)-(.+)"
+        expected = [(u'%(_0)s-%(_1)s', ['_0', '_1'])]
+        result = regex_helper.normalize(pattern)
+        self.assertEqual(result, expected)
+
+    def test_group_ignored(self):
+        pattern = r"(?i)(?L)(?m)(?s)(?u)(?#)"
+        expected = [(u'', [])]
+        result = regex_helper.normalize(pattern)
+        self.assertEqual(result, expected)
+
+    def test_group_noncapturing(self):
+        pattern = r"(?:non-capturing)"
+        expected = [(u'non-capturing', [])]
+        result = regex_helper.normalize(pattern)
+        self.assertEqual(result, expected)
+
+    def test_group_named(self):
+        pattern = r"(?P<first_group_name>.*)-(?P<second_group_name>.*)"
+        expected = [(u'%(first_group_name)s-%(second_group_name)s',
+                    ['first_group_name', 'second_group_name'])]
+        result = regex_helper.normalize(pattern)
+        self.assertEqual(result, expected)
+
+    def test_group_backreference(self):
+        pattern = r"(?P<first_group_name>.*)-(?P=first_group_name)"
+        expected = [(u'%(first_group_name)s-%(first_group_name)s',
+                    ['first_group_name'])]
+        result = regex_helper.normalize(pattern)
+        self.assertEqual(result, expected)