diff --git a/Lib/test/test_fileio.py b/Lib/test/test_fileio.py
index 9f70a73..a8b15fa 100644
--- a/Lib/test/test_fileio.py
+++ b/Lib/test/test_fileio.py
@@ -227,6 +227,10 @@
             except:
                 pass
 
+    def testInvalidInit(self):
+        self.assertRaises(TypeError, _fileio._FileIO, "1", 0, 0)
+
+
 def test_main():
     # Historically, these tests have been sloppy about removing TESTFN.
     # So get rid of it no matter what.