tarfile module does not correctly choose compression algorithms

Lib/test/test_tarfile.py

 import sys
 import os
 import io
 from hashlib import md5
 
 import unittest
 import tarfile
 
 from test import support, script_helper
 
@@ skipping 1987 matching lines @@
     def test_create_command_dot_started_filename(self):
         tar_name = os.path.join(TEMPDIR, ".testtar")
         files = [support.findfile('tokenize_tests.txt')]
         try:
             out = self.tarfilecmd('-c', tar_name, *files)
             self.assertEqual(out, b'')
             with tarfile.open(tar_name) as tar:
                 tar.getmembers()
         finally:
             support.unlink(tar_name)
+
+    def test_create_command_filetype(self):
+        files = [support.findfile('tokenize_tests.txt'),
+                 support.findfile('tokenize_tests-no-coding-cookie-'
+                                  'and-utf8-bom-sig-only.txt')]
+
+        for filetype in (GzipTest, Bz2Test, LzmaTest):
+            if not filetype.open:
+                continue
+            try:
+                filename = tmpname + '.' + filetype.suffix
+                out = self.tarfilecmd('-c', filename, *files)
+                with filetype.taropen(filename, 'r') as tar:
+                    pass
+            finally:
+                support.unlink(filename)
 
     def test_extract_command(self):
         self.make_simple_tarfile(tmpname)
         for opt in '-e', '--extract':
             try:
                 with support.temp_cwd(tarextdir):
                     out = self.tarfilecmd(opt, tmpname)
                 self.assertEqual(out, b'')
             finally:
                 support.rmtree(tarextdir)
@@ skipping 165 matching lines @@
             testtarnames.append(c.tarname)
             with c.open(c.tarname, "wb") as tar:
                 tar.write(data)
 
 def tearDownModule():
     if os.path.exists(TEMPDIR):
         support.rmtree(TEMPDIR)
 
 if __name__ == "__main__":
     unittest.main()