Normalize the encoding names for Latin-1 and UTF-8 to
'latin-1' and 'utf-8'.

These are optimized in the Python Unicode implementation
to result in more direct processing, bypassing the codec
registry.

Also see issue11303.
diff --git a/Lib/test/test_bytes.py b/Lib/test/test_bytes.py
index e5c7ccd..84867bb 100644
--- a/Lib/test/test_bytes.py
+++ b/Lib/test/test_bytes.py
@@ -188,24 +188,26 @@
 
     def test_encoding(self):
         sample = "Hello world\n\u1234\u5678\u9abc"
-        for enc in ("utf8", "utf16"):
+        for enc in ("utf-8", "utf-16"):
             b = self.type2test(sample, enc)
             self.assertEqual(b, self.type2test(sample.encode(enc)))
-        self.assertRaises(UnicodeEncodeError, self.type2test, sample, "latin1")
-        b = self.type2test(sample, "latin1", "ignore")
+        self.assertRaises(UnicodeEncodeError, self.type2test, sample, "latin-1")
+        b = self.type2test(sample, "latin-1", "ignore")
         self.assertEqual(b, self.type2test(sample[:-3], "utf-8"))
 
     def test_decode(self):
         sample = "Hello world\n\u1234\u5678\u9abc\def0\def0"
-        for enc in ("utf8", "utf16"):
+        for enc in ("utf-8", "utf-16"):
             b = self.type2test(sample, enc)
             self.assertEqual(b.decode(enc), sample)
         sample = "Hello world\n\x80\x81\xfe\xff"
-        b = self.type2test(sample, "latin1")
-        self.assertRaises(UnicodeDecodeError, b.decode, "utf8")
-        self.assertEqual(b.decode("utf8", "ignore"), "Hello world\n")
-        self.assertEqual(b.decode(errors="ignore", encoding="utf8"),
+        b = self.type2test(sample, "latin-1")
+        self.assertRaises(UnicodeDecodeError, b.decode, "utf-8")
+        self.assertEqual(b.decode("utf-8", "ignore"), "Hello world\n")
+        self.assertEqual(b.decode(errors="ignore", encoding="utf-8"),
                          "Hello world\n")
+        # Default encoding is utf-8
+        self.assertEqual(self.type2test(b'\xe2\x98\x83').decode(), '\u2603')
 
     def test_from_int(self):
         b = self.type2test(0)