gh-91575: Update case-insensitive matching in re to the latest Unicode version (GH-91580)

1 files changed, 49 insertions, 6 deletions

diff --git a/Lib/test/test_re.py b/Lib/test/test_re.py
index 959582e..a1c27c9 100644
--- a/Lib/test/test_re.py
+++ b/Lib/test/test_re.py
@@ -859,16 +859,30 @@ class ReTests(unittest.TestCase):
         self.assertEqual(re.match(r"((a)\s(abc|a))", "a a", re.I).group(1), "a a")
         self.assertEqual(re.match(r"((a)\s(abc|a)*)", "a aa", re.I).group(1), "a aa")
 
-        assert '\u212a'.lower() == 'k' # 'K'
+        # Two different characters have the same lowercase.
+        assert 'K'.lower() == '\u212a'.lower() == 'k' # 'K'
         self.assertTrue(re.match(r'K', '\u212a', re.I))
         self.assertTrue(re.match(r'k', '\u212a', re.I))
         self.assertTrue(re.match(r'\u212a', 'K', re.I))
         self.assertTrue(re.match(r'\u212a', 'k', re.I))
-        assert '\u017f'.upper() == 'S' # 'ſ'
+
+        # Two different characters have the same uppercase.
+        assert 's'.upper() == '\u017f'.upper() == 'S' # 'ſ'
         self.assertTrue(re.match(r'S', '\u017f', re.I))
         self.assertTrue(re.match(r's', '\u017f', re.I))
         self.assertTrue(re.match(r'\u017f', 'S', re.I))
         self.assertTrue(re.match(r'\u017f', 's', re.I))
+
+        # Two different characters have the same uppercase. Unicode 9.0+.
+        assert '\u0432'.upper() == '\u1c80'.upper() == '\u0412' # 'в', 'ᲀ', 'В'
+        self.assertTrue(re.match(r'\u0412', '\u0432', re.I))
+        self.assertTrue(re.match(r'\u0412', '\u1c80', re.I))
+        self.assertTrue(re.match(r'\u0432', '\u0412', re.I))
+        self.assertTrue(re.match(r'\u0432', '\u1c80', re.I))
+        self.assertTrue(re.match(r'\u1c80', '\u0412', re.I))
+        self.assertTrue(re.match(r'\u1c80', '\u0432', re.I))
+
+        # Two different characters have the same multicharacter uppercase.
         assert '\ufb05'.upper() == '\ufb06'.upper() == 'ST' # 'ſt', 'st'
         self.assertTrue(re.match(r'\ufb05', '\ufb06', re.I))
         self.assertTrue(re.match(r'\ufb06', '\ufb05', re.I))
@@ -882,16 +896,31 @@ class ReTests(unittest.TestCase):
         self.assertTrue(re.match(br'[19a]', b'a', re.I))
         self.assertTrue(re.match(br'[19a]', b'A', re.I))
         self.assertTrue(re.match(br'[19A]', b'a', re.I))
-        assert '\u212a'.lower() == 'k' # 'K'
+
+        # Two different characters have the same lowercase.
+        assert 'K'.lower() == '\u212a'.lower() == 'k' # 'K'
         self.assertTrue(re.match(r'[19K]', '\u212a', re.I))
         self.assertTrue(re.match(r'[19k]', '\u212a', re.I))
         self.assertTrue(re.match(r'[19\u212a]', 'K', re.I))
         self.assertTrue(re.match(r'[19\u212a]', 'k', re.I))
-        assert '\u017f'.upper() == 'S' # 'ſ'
+
+        # Two different characters have the same uppercase.
+        assert 's'.upper() == '\u017f'.upper() == 'S' # 'ſ'
         self.assertTrue(re.match(r'[19S]', '\u017f', re.I))
         self.assertTrue(re.match(r'[19s]', '\u017f', re.I))
         self.assertTrue(re.match(r'[19\u017f]', 'S', re.I))
         self.assertTrue(re.match(r'[19\u017f]', 's', re.I))
+
+        # Two different characters have the same uppercase. Unicode 9.0+.
+        assert '\u0432'.upper() == '\u1c80'.upper() == '\u0412' # 'в', 'ᲀ', 'В'
+        self.assertTrue(re.match(r'[19\u0412]', '\u0432', re.I))
+        self.assertTrue(re.match(r'[19\u0412]', '\u1c80', re.I))
+        self.assertTrue(re.match(r'[19\u0432]', '\u0412', re.I))
+        self.assertTrue(re.match(r'[19\u0432]', '\u1c80', re.I))
+        self.assertTrue(re.match(r'[19\u1c80]', '\u0412', re.I))
+        self.assertTrue(re.match(r'[19\u1c80]', '\u0432', re.I))
+
+        # Two different characters have the same multicharacter uppercase.
         assert '\ufb05'.upper() == '\ufb06'.upper() == 'ST' # 'ſt', 'st'
         self.assertTrue(re.match(r'[19\ufb05]', '\ufb06', re.I))
         self.assertTrue(re.match(r'[19\ufb06]', '\ufb05', re.I))
@@ -915,16 +944,30 @@ class ReTests(unittest.TestCase):
         self.assertTrue(re.match(r'[\U00010400-\U00010427]', '\U00010428', re.I))
         self.assertTrue(re.match(r'[\U00010400-\U00010427]', '\U00010400', re.I))
 
-        assert '\u212a'.lower() == 'k' # 'K'
+        # Two different characters have the same lowercase.
+        assert 'K'.lower() == '\u212a'.lower() == 'k' # 'K'
         self.assertTrue(re.match(r'[J-M]', '\u212a', re.I))
         self.assertTrue(re.match(r'[j-m]', '\u212a', re.I))
         self.assertTrue(re.match(r'[\u2129-\u212b]', 'K', re.I))
         self.assertTrue(re.match(r'[\u2129-\u212b]', 'k', re.I))
-        assert '\u017f'.upper() == 'S' # 'ſ'
+
+        # Two different characters have the same uppercase.
+        assert 's'.upper() == '\u017f'.upper() == 'S' # 'ſ'
         self.assertTrue(re.match(r'[R-T]', '\u017f', re.I))
         self.assertTrue(re.match(r'[r-t]', '\u017f', re.I))
         self.assertTrue(re.match(r'[\u017e-\u0180]', 'S', re.I))
         self.assertTrue(re.match(r'[\u017e-\u0180]', 's', re.I))
+
+        # Two different characters have the same uppercase. Unicode 9.0+.
+        assert '\u0432'.upper() == '\u1c80'.upper() == '\u0412' # 'в', 'ᲀ', 'В'
+        self.assertTrue(re.match(r'[\u0411-\u0413]', '\u0432', re.I))
+        self.assertTrue(re.match(r'[\u0411-\u0413]', '\u1c80', re.I))
+        self.assertTrue(re.match(r'[\u0431-\u0433]', '\u0412', re.I))
+        self.assertTrue(re.match(r'[\u0431-\u0433]', '\u1c80', re.I))
+        self.assertTrue(re.match(r'[\u1c80-\u1c82]', '\u0412', re.I))
+        self.assertTrue(re.match(r'[\u1c80-\u1c82]', '\u0432', re.I))
+
+        # Two different characters have the same multicharacter uppercase.
         assert '\ufb05'.upper() == '\ufb06'.upper() == 'ST' # 'ſt', 'st'
         self.assertTrue(re.match(r'[\ufb04-\ufb05]', '\ufb06', re.I))
         self.assertTrue(re.match(r'[\ufb06-\ufb07]', '\ufb05', re.I))