def test_writeorg(self):

       tmppath = py.test.ensuretemp('test_writeorg').ensure('stderr',

                                                            file=True)

       tmpfp = tmppath.open('w+b')

       try:

           cap = py.io.FDCapture(tmpfp.fileno())

           print >>tmpfp, 'foo'

->         cap.writeorg('bar\n')

       finally:

           tmpfp.close()

       f = cap.done()

       scap = f.read()

       assert scap == 'foo\n'

       stmp = tmppath.read()

       assert stmp == "bar\n"