def METHOD_NAME(self):
    self.load_phase('ar.jcpds')
    first_line_position = self.widget.cake_widget.phases[0].line_items[0].getPos()
    self.model.phase_model.set_pressure(0, 4)
    self.assertNotEqual(first_line_position,
                        self.widget.cake_widget.phases[0].line_items[0].getPos())