我有一个组件库,我正在使用Jest和react-testing-library编写单元测试。基于某些道具或事件,我想验证某些元素没有被渲染。

如果未找到元素,则在react-testing-library中抛出和错误,导致在expect函数触发之前测试失败。

如何使用react-testing-library测试不存在的东西?


当前回答

对我来说(如果你想使用getbytestd):

expect(() => getByTestId('time-label')).toThrow()

其他回答

希望这对你有所帮助

该表显示了函数错误的原因/时间

哪些函数是异步的

函数的return语句是什么

来自DOM测试库文档-出现和消失

Asserting elements are not present The standard getBy methods throw an error when they can't find an element, so if you want to make an assertion that an element is not present in the DOM, you can use queryBy APIs instead: const submitButton = screen.queryByText('submit') expect(submitButton).toBeNull() // it doesn't exist The queryAll APIs version return an array of matching nodes. The length of the array can be useful for assertions after elements are added or removed from the DOM. const submitButtons = screen.queryAllByText('submit') expect(submitButtons).toHaveLength(2) // expect 2 elements not.toBeInTheDocument The jest-dom utility library provides the .toBeInTheDocument() matcher, which can be used to assert that an element is in the body of the document, or not. This can be more meaningful than asserting a query result is null. import '@testing-library/jest-dom/extend-expect' // use `queryBy` to avoid throwing an error with `getBy` const submitButton = screen.queryByText('submit') expect(submitButton).not.toBeInTheDocument()

你必须使用querybytestd而不是getbytestd。

这里是一个代码示例,我想测试是否组件与“汽车”id不存在。

 describe('And there is no car', () => {
  it('Should not display car mark', () => {
    const props = {
      ...defaultProps,
      base: null,
    }
    const { queryByTestId } = render(
      <IntlProvider locale="fr" messages={fr}>
        <CarContainer{...props} />
      </IntlProvider>,
    );
    expect(queryByTestId(/car/)).toBeNull();
  });
});

您可以使用react-native-testing-library "getAllByType",然后检查该组件是否为空。优点是不必设置testd,也应该与第三方组件一起工作

 it('should contain Customer component', () => {
    const component = render(<Details/>);
    const customerComponent = component.getAllByType(Customer);
    expect(customerComponent).not.toBeNull();
  });

queryByRole的默认行为是只查找一个元素。如果不是,则抛出错误。因此,如果您捕捉到一个错误,这意味着当前查询找到0个元素

expect(
   ()=>screen.getByRole('button')
).toThrow()

如果没有找到任何东西,getByRole返回'null'

 expect(screen.queryByRole('button')).toEqual((null))

findByRole是异步运行的,因此它返回一个Promise。如果它没有找到一个元素,它就拒绝承诺。如果你正在使用这个,你需要运行异步回调

test("testing", async () => {
  let nonExist = false;
  try {
    await screen.findByRole("button");
  } catch (error) {
    nonExist = true;
  }
  expect(nonExist).toEqual(true);
});