javascript - React 测试库 - 未包含在 act() 错误中

Question

我在使用 react-testing-library 测试切换组件时遇到问题。

单击图标（包装在按钮组件中）时，我希望文本从“已验证”变为“未验证”。此外，在有状态更新的地方调用一个函数。

但是，单击事件似乎不起作用，并且出现以下错误：

> jest "MyFile.spec.tsx"

 FAIL  src/my/path/__tests__/MyFile.spec.tsx
  component MyFile
    ✓ renders when opened (94 ms)
    ✓ renders with items (33 ms)
    ✕ toggles verification status on click of icon button (100 ms)


  console.error
    Warning: An update to MyFile inside a test was not wrapped in act(...).
    
    When testing, code that causes React state updates should be wrapped into act(...):
    
    act(() => {
      /* fire events that update state */
    });
    /* assert on the output */
    
    This ensures that you're testing the behavior the user would see in the browser. Learn more at https://reactjs.org/link/wrap-tests-with-act
        at MyFile (/path/to/myfile.tsx:44:3)
        at ThemeProvider (/users/node_modules/@material-ui/styles/ThemeProvider/ThemeProvider.js:48:24)

      123 |       );
      124 |     } finally {
    > 125 |       setIsLoading(false);
          |       ^
      126 |     }
      127 |   };
      128 |

      at printWarning (node_modules/react-dom/cjs/react-dom.development.js:67:30)
      at error (node_modules/react-dom/cjs/react-dom.development.js:43:5)
      at warnIfNotCurrentlyActingUpdatesInDEV (node_modules/react-dom/cjs/react-dom.development.js:24064:9)
      at dispatchAction (node_modules/react-dom/cjs/react-dom.development.js:16135:9)
      at handleConfirm (src/modules/myfile.tsx:125:7)

在我的代码中，我有一个这样的函数：

const handleSubmit = async() => {
  if(isLoading) {
    return;
  }

  try {
    setIsLoading(true);
    await myFunctionCalls();
  } catch (error){
    console.log(error)
  } finally {
    setIsLoading(false)
  }
};

我的测试看起来与此类似：

test('toggles verification status on click of icon button', async () => {
    renderWithTheme(
    <MyComponent/>,
   );

  const updateVerificationMock = jest.fn();
  const callFunctionWithSerializedPayloadMock =
    callFunctionWithSerializedPayload as jest.Mock;
  callFunctionWithSerializedPayloadMock.mockImplementation(
    () => updateVerificationMock,
  );

    const button = screen.getByRole('button', {name: 'Remove approval'});
    fireEvent.click(button);

    await act(async () => {
      expect(myFunctionCalls).toHaveBeenCalledTimes(1);
    });
    expect(await screen.findByText('unverified')).toBeInTheDocument();
  });

当函数调用被调用一次时，第一个期望通过，但是我从上面遇到了 act() 错误，并且还有一个失败，因为文本似乎没有从verifiedto切换unverified。

我知道通常行为错误是异步/等待调用发生的问题，但我认为 findByText 应该等待，而且似乎还有另一个我没有在这里遇到的问题。有关如何调试/改进此测试的任何帮助？

标签： javascriptreactjsasync-awaitjestjsreact-testing-library

Answer 1

单击Remove Approval按钮时，此处会调用 3 个异步函数。

首先，您将加载状态设置为true，因此它将加载然后调用异步函数（myFunctionCalls），最后，加载器将在加载状态设置为false后消失。

为了解决它，我们必须先等待加载出现，然后调用 myFunctionCalls，然后再等待加载消失。

test("toggles verification status on click of icon button", async () => {
  renderWithTheme(<MyComponent />);

  const updateVerificationMock = jest.fn();
  const callFunctionWithSerializedPayloadMock =
    callFunctionWithSerializedPayload as jest.Mock;
  callFunctionWithSerializedPayloadMock.mockImplementation(
    () => updateVerificationMock
  );

  const button = screen.getByRole("button", { name: "Remove approval" });
  fireEvent.click(button);

  expect(await screen.findByText(/loading/i)).toBeInTheDocument();

  await waitFor(() => {
    expect(myFunctionCalls).toHaveBeenCalledTimes(1);
  });

  await waitForTheElementToBeRemoved(() => {
    expect(screen.queryByText(/loading/i)).not.toBeInTheDocument();
  });


  expect(await screen.findByText("unverified")).toBeInTheDocument();
});

如果您没有加载文本，则可以使用act(() => jest.advanceTimersByTime(500));将时间延长至 500 毫秒。当时间达到 500 毫秒时，异步功能将被解决。

beforeEach(() => {
  jest.useFakeTimers();
})

afterEach(() => {
  jest.runAllPendingTimers();
  jest.useRealTimers()
})

test("toggles verification status on click of icon button", async () => {
  renderWithTheme(<MyComponent />);

  const updateVerificationMock = jest.fn();
  const callFunctionWithSerializedPayloadMock =
    callFunctionWithSerializedPayload as jest.Mock;
  callFunctionWithSerializedPayloadMock.mockImplementation(
    () => updateVerificationMock
  );

  const button = screen.getByRole("button", { name: "Remove approval" });
  fireEvent.click(button);

  act(() => jest.advanceTimersByTime(500));

  await waitFor(() => {
    expect(myFunctionCalls).toHaveBeenCalledTimes(1);
  });

  act(() => jest.advanceTimersByTime(500));

  expect(await screen.findByText("unverified")).toBeInTheDocument();
});