diff -r 7c717d423160 Lib/unittest/runner.py
--- a/Lib/unittest/runner.py	Wed Dec 19 15:28:46 2012 -0600
+++ b/Lib/unittest/runner.py	Wed Jan 02 18:33:15 2013 -0600
@@ -36,7 +36,10 @@
 
     def __init__(self, stream, descriptions, verbosity):
         super(TextTestResult, self).__init__(stream, descriptions, verbosity)
-        self.stream = stream
+        if hasattr(stream, "writeln"):
+            self.stream = stream
+        else:
+            self.stream = _WritelnDecorator(stream)
         self.showAll = verbosity > 1
         self.dots = verbosity == 1
         self.descriptions = descriptions
diff -r 7c717d423160 Lib/unittest/test/test_result.py
--- a/Lib/unittest/test/test_result.py	Wed Dec 19 15:28:46 2012 -0600
+++ b/Lib/unittest/test/test_result.py	Wed Jan 02 18:33:15 2013 -0600
@@ -294,6 +294,23 @@
             self.assertTrue(result.failfast)
         result = runner.run(test)
 
+    def testStreamDecoratedWithWriteln(self):
+        stream_without_writeln = io.StringIO()
+        result = unittest.TextTestResult(stream=stream_without_writeln,
+                                         descriptions=True, verbosity=2)
+        result.stream.writeln('test')
+        self.assertEqual(result.stream.getvalue(), 'test\n')
+        with self.assertRaises(AttributeError):
+            stream_without_writeln.writeln
+
+    def testStreamWithWritelnIsNotDecorated(self):
+        stream_with_writeln = io.StringIO()
+        stream_with_writeln.writeln = stream_with_writeln.write
+        result = unittest.TextTestResult(stream=stream_with_writeln,
+                                         descriptions=True, verbosity=2)
+        self.assertFalse(
+            isinstance(result.stream, unittest.runner._WritelnDecorator))
+
 
 classDict = dict(unittest.TestResult.__dict__)
 for m in ('addSkip', 'addExpectedFailure', 'addUnexpectedSuccess',