'No crash on empty data'

def test_empty_data(self):

    data = Table('iris')
    widget = self.widget
    widget.default_method_index = widget.MODEL_BASED_IMPUTER
    widget.default_method = widget.methods[widget.default_method_index]
    self.send_signal(self.widget.Inputs.data, data)
    widget.unconditional_commit()
    imp_data = self.get_output(self.widget.Outputs.data)
    np.testing.assert_equal(imp_data.X, data.X)
    np.testing.assert_equal(imp_data.Y, data.Y)
    self.send_signal(self.widget.Inputs.data, Table(data.domain))
    widget.unconditional_commit()
    imp_data = self.get_output(self.widget.Outputs.data)
    self.assertEqual(len(imp_data), 0)
