'Check if error message appears and then disappears when
data is removed from input'

def test_error_message(self):

    self.widget.controls.sampling_type.buttons[2].click()
    self.send_signal('Data', self.iris)
    self.assertFalse(self.widget.Error.too_many_folds.is_shown())
    self.send_signal('Data', self.iris[:5])
    self.assertTrue(self.widget.Error.too_many_folds.is_shown())
    self.send_signal('Data', None)
    self.assertFalse(self.widget.Error.too_many_folds.is_shown())
    self.send_signal('Data', Table(self.iris.domain))
    self.assertTrue(self.widget.Error.no_data.is_shown())
