'When logfile is empty or set to C{-}, L{app.AppLogger._getLogObserver}
returns a log observer pointing at C{sys.stdout}.'

def test_getLogObserverStdout(self):

    logger = app.AppLogger({'logfile': '-'})
    logFiles = _patchTextFileLogObserver(self.patch)
    logger._getLogObserver()
    self.assertEqual(len(logFiles), 1)
    self.assertIs(logFiles[0], sys.stdout)
    logger = app.AppLogger({'logfile': ''})
    logger._getLogObserver()
    self.assertEqual(len(logFiles), 2)
    self.assertIs(logFiles[1], sys.stdout)
