Issue #5815: Fixed support for locales with modifiers.  Fixed support for
locale encodings with hyphens.
diff --git a/Lib/test/test_locale.py b/Lib/test/test_locale.py
index 48bf36d..76202df 100644
--- a/Lib/test/test_locale.py
+++ b/Lib/test/test_locale.py
@@ -365,6 +365,64 @@
         self.assertLess(locale.strxfrm('à'), locale.strxfrm('b'))
 
 
+class NormalizeTest(unittest.TestCase):
+    def check(self, localename, expected):
+        self.assertEqual(locale.normalize(localename), expected, msg=localename)
+
+    def test_locale_alias(self):
+        for localename, alias in locale.locale_alias.items():
+            with self.subTest(locale=(localename, alias)):
+                self.check(localename, alias)
+
+    def test_empty(self):
+        self.check('', '')
+
+    def test_c(self):
+        self.check('c', 'C')
+        self.check('posix', 'C')
+
+    def test_english(self):
+        self.check('en', 'en_US.ISO8859-1')
+        self.check('EN', 'en_US.ISO8859-1')
+        self.check('en_US', 'en_US.ISO8859-1')
+        self.check('en_us', 'en_US.ISO8859-1')
+        self.check('en_GB', 'en_GB.ISO8859-1')
+        self.check('en_US.UTF-8', 'en_US.UTF-8')
+        self.check('en_US.utf8', 'en_US.UTF-8')
+        self.check('en_US:UTF-8', 'en_US.UTF-8')
+        self.check('en_US.ISO8859-1', 'en_US.ISO8859-1')
+        self.check('en_US.US-ASCII', 'en_US.ISO8859-1')
+        self.check('english', 'en_EN.ISO8859-1')
+
+    def test_hyphenated_encoding(self):
+        self.check('az_AZ.iso88599e', 'az_AZ.ISO8859-9E')
+        self.check('az_AZ.ISO8859-9E', 'az_AZ.ISO8859-9E')
+        self.check('tt_RU.koi8c', 'tt_RU.KOI8-C')
+        self.check('tt_RU.KOI8-C', 'tt_RU.KOI8-C')
+        self.check('lo_LA.cp1133', 'lo_LA.IBM-CP1133')
+        self.check('lo_LA.ibmcp1133', 'lo_LA.IBM-CP1133')
+        self.check('lo_LA.IBM-CP1133', 'lo_LA.IBM-CP1133')
+        self.check('uk_ua.microsoftcp1251', 'uk_UA.CP1251')
+        self.check('uk_ua.microsoft-cp1251', 'uk_UA.CP1251')
+        self.check('ka_ge.georgianacademy', 'ka_GE.GEORGIAN-ACADEMY')
+        self.check('ka_GE.GEORGIAN-ACADEMY', 'ka_GE.GEORGIAN-ACADEMY')
+        self.check('cs_CZ.iso88592', 'cs_CZ.ISO8859-2')
+        self.check('cs_CZ.ISO8859-2', 'cs_CZ.ISO8859-2')
+
+    def test_euro_modifier(self):
+        self.check('de_DE@euro', 'de_DE.ISO8859-15')
+        self.check('en_US.ISO8859-15@euro', 'en_US.ISO8859-15')
+
+    def test_latin_modifier(self):
+        self.check('be_BY.UTF-8@latin', 'be_BY.UTF-8@latin')
+        self.check('sr_RS.UTF-8@latin', 'sr_RS.UTF-8@latin')
+
+    def test_valencia_modifier(self):
+        self.check('ca_ES.UTF-8@valencia', 'ca_ES.UTF-8@valencia')
+        self.check('ca_ES@valencia', 'ca_ES.ISO8859-1@valencia')
+        self.check('ca@valencia', 'ca_ES.ISO8859-1@valencia')
+
+
 class TestMiscellaneous(unittest.TestCase):
     def test_getpreferredencoding(self):
         # Invoke getpreferredencoding to make sure it does not cause exceptions.