diff --git a/Lib/test/test_fileio.py b/Lib/test/test_fileio.py
index 0404a19..a11d3ba 100644
--- a/Lib/test/test_fileio.py
+++ b/Lib/test/test_fileio.py
@@ -6,7 +6,7 @@
 from array import array
 from weakref import proxy
 
-from test.support import TESTFN, findfile, run_unittest
+from test.support import TESTFN, findfile, check_warnings, run_unittest
 from collections import UserList
 
 import _fileio
@@ -240,6 +240,14 @@
     def testInvalidInit(self):
         self.assertRaises(TypeError, _fileio._FileIO, "1", 0, 0)
 
+    def testWarnings(self):
+        with check_warnings() as w:
+            self.assertEqual(w.warnings, [])
+            self.assertRaises(TypeError, _fileio._FileIO, [])
+            self.assertEqual(w.warnings, [])
+            self.assertRaises(ValueError, _fileio._FileIO, "/some/invalid/name", "rt")
+            self.assertEqual(w.warnings, [])
+
 
 def test_main():
     # Historically, these tests have been sloppy about removing TESTFN.
diff --git a/Lib/test/test_io.py b/Lib/test/test_io.py
index 1f0295c..83d363d 100644
--- a/Lib/test/test_io.py
+++ b/Lib/test/test_io.py
@@ -1260,6 +1260,7 @@
             else:
                 self.assert_(issubclass(obj, io.IOBase))
 
+
 def test_main():
     support.run_unittest(IOTest, BytesIOTest, StringIOTest,
                               BufferedReaderTest, BufferedWriterTest,