diff -r 18906f36f033 Lib/test/test_tarfile.py
--- a/Lib/test/test_tarfile.py	Mon Mar 24 18:18:39 2014 +0100
+++ b/Lib/test/test_tarfile.py	Mon Mar 24 19:24:58 2014 +0100
@@ -2132,6 +2132,16 @@
         self._test_partial_input("r:bz2")
 
 
+class OpenFileobjNameInteger(unittest.TestCase):
+    # Issue 21044: tarfile.open() should handle fileobj with an integer 'name'
+    # attribute.
+
+    def test_open_fobj_integer_name(self):
+        import tempfile
+        with tempfile.TemporaryFile() as fobj:
+            tarfile.open(fileobj=fobj, mode='w')
+
+
 def setUpModule():
     support.unlink(TEMPDIR)
     os.makedirs(TEMPDIR)