'L{_ErrorFormatter.formatError} should use L{os.strerror} to format
error messages if it is constructed with only an error tab which does
not contain the error code it is called with.'

def test_emptyErrorTab(self):

    error = 1
    self.assertNotEqual(self.probeErrorCode, error)
    formatter = _ErrorFormatter(None, None, {error: 'wrong    message'})
    message = formatter.formatError(self.probeErrorCode)
    self.assertEqual(message, os.strerror(self.probeErrorCode))
