Added test case based on recommended test cases from RFC 4648 (GH-27747)

(cherry picked from commit 230403a)

Co-authored-by: andrei kulakov <andrei.avk@gmail.com>

Author: miss-islington

Lib/test/test_base64.py

@@ -714,6 +714,45 @@ def test_decode_nonascii_str(self):
     def test_ErrorHeritage(self):
         self.assertTrue(issubclass(binascii.Error, ValueError))
 
+    def test_RFC4648_test_cases(self):
+        # test cases from RFC 4648 section 10
+        b64encode = base64.b64encode
+        b32hexencode = base64.b32hexencode
+        b32encode = base64.b32encode
+        b16encode = base64.b16encode
+
+        self.assertEqual(b64encode(b""), b"")
+        self.assertEqual(b64encode(b"f"), b"Zg==")
+        self.assertEqual(b64encode(b"fo"), b"Zm8=")
+        self.assertEqual(b64encode(b"foo"), b"Zm9v")
+        self.assertEqual(b64encode(b"foob"), b"Zm9vYg==")
+        self.assertEqual(b64encode(b"fooba"), b"Zm9vYmE=")
+        self.assertEqual(b64encode(b"foobar"), b"Zm9vYmFy")
+
+        self.assertEqual(b32encode(b""), b"")
+        self.assertEqual(b32encode(b"f"), b"MY======")
+        self.assertEqual(b32encode(b"fo"), b"MZXQ====")
+        self.assertEqual(b32encode(b"foo"), b"MZXW6===")
+        self.assertEqual(b32encode(b"foob"), b"MZXW6YQ=")
+        self.assertEqual(b32encode(b"fooba"), b"MZXW6YTB")
+        self.assertEqual(b32encode(b"foobar"), b"MZXW6YTBOI======")
+
+        self.assertEqual(b32hexencode(b""), b"")
+        self.assertEqual(b32hexencode(b"f"), b"CO======")
+        self.assertEqual(b32hexencode(b"fo"), b"CPNG====")
+        self.assertEqual(b32hexencode(b"foo"), b"CPNMU===")
+        self.assertEqual(b32hexencode(b"foob"), b"CPNMUOG=")
+        self.assertEqual(b32hexencode(b"fooba"), b"CPNMUOJ1")
+        self.assertEqual(b32hexencode(b"foobar"), b"CPNMUOJ1E8======")
+
+        self.assertEqual(b16encode(b""), b"")
+        self.assertEqual(b16encode(b"f"), b"66")
+        self.assertEqual(b16encode(b"fo"), b"666F")
+        self.assertEqual(b16encode(b"foo"), b"666F6F")
+        self.assertEqual(b16encode(b"foob"), b"666F6F62")
+        self.assertEqual(b16encode(b"fooba"), b"666F6F6261")
+        self.assertEqual(b16encode(b"foobar"), b"666F6F626172")
+
 
 class TestMain(unittest.TestCase):
     def tearDown(self):