开玩笑说，测试一个道具叫做

Question

我有一个带有道具的组件，这是一个叫做changeReason()

的动作

然后，当我按下一个按钮时，我有一个函数被调用。功能是：

const handleNext = React.useCallback(() => {
  if (!reason) {
    changeReason({
      code: defaultReason,
      value: defaultReason
    });
  }

}

我想测试调用changeReason()道具，我正在尝试进行如下测试：

const changeReason = jest.fn();

const rendered = render(
  <TransactionReason
    changeReason={changeReason}
    reason={null}
  />
);

// When some button is pressed...
const reasonNext = rendered.getByTestId('reasonButton');
// it must fire an event
fireEvent.press(reasonNext);

const FakeFun = jest.spyOn(rendered, 'changeReason');
expect(FakeFun).toHaveBeenCalled();

我得到：

Cannot spy the handleNext property because it is not a function; undefined given instead

我如何测试我正在调用该动作？