是否可以在节点中为没有 catch 块的承诺编写一个笑话单元测试？

Question

有什么问题

我正在尝试编写一个带有用户登录的基本 React Django 样板文件。我正在使用 react-saga.

处理登录流程

我有一个调用登录函数的 saga，它会 ping 服务器并获取令牌。 saga 处理所有的错误处理。如果该调用失败，错误将成功返回以做出反应并显示给用户。它工作正常。

我正在尝试为登录功能编写单元测试。我认为节点正在捕获我的错误：UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch().

我猜是因为 saga 在现实中捕获了它，所以 node 不会抛出该错误。

这是否意味着我无法对登录函数抛出未捕获的错误进行单元测试？

我不应该费心测试这个吗？

代码

这是调用服务器的函数。

 # Auth login function

login(email, password) {
    // If user is already logged in return true.
    if (auth.loggedIn()) return Promise.resolve(true);
    const credentials = btoa(`${email}:${password}`);
    // Request to login
    return axios({
        method: "post",
        url: `${SERVER_URL}/api/v1/accounts/login/`,
        headers: {
            Accept: "application/json",
            "Content-Type": "application/json",
            Authorization: `Basic ${credentials}`
        }
    }).then(response => {
        // Save token to local storage
        if (response.data.token) {
            localStorage.auth_token = response.data.token;
        } else {
            // To Do-- throw error if server fails to return one
        }
        return Promise.resolve(true);
    });
}

那么这就是处理逻辑的传奇。

export function* authorize({
    email,
    password,
    isRegistering,
    firstName,
    lastName
}) {
    // We send an action that tells Redux we're sending a request
    yield put({ type: SENDING_REQUEST, sending: true });

    // We then try to register or log in the user, depending on the request
    try {
        let response;

        // For either log in or registering, we call the proper function in the `auth`
        // module, which is asynchronous. Because we're using generators, we can work
        // as if it's synchronous because we pause execution until the call is done
        // with `yield`!
        if (isRegistering) {
            response = yield call(
                register,
                email,
                password,
                firstName,
                lastName
            );
        } else {
            response = yield call(login, email, password);
        }

        return response;
    } catch (error) {
        // If we get an error we send Redux the appropriate action and return
        yield put({
            type: REQUEST_ERROR,
            error: error.response.data,
            sending: false
        });

        return false;
    } finally {
        // When done, we tell Redux we're not in the middle of a request any more
        yield put({ type: SENDING_REQUEST, sending: false });
    }
}

那么这是我的单元测试：

describe("login function", () => {
    let mock;

    beforeEach(() => {
        mock = new MockAdapter(axios);
        localStorage.clear();
    });

    afterEach(() => {
        // We need to clear mocks
        // and remove tokens from local storage to prevent
        // us from staying logged in
        mock.restore();
    });

    test("Check that exception thrown on server error", () => {
        // Mock loggedin function to throw error
        mock.onPost().reply(500);
        Test that error is uncaught.
        expect(() => {
            auth.login("test@example.com", "pass").then(value => {
                console.log(value);
            });
        }).toThrow();

    });
});

Answer 1

你可以测试一下。 toThrow 方法用于捕获抛出的错误，但 promise 拒绝错误因此需要使用不同的 API。要捕获您的错误 .rejects.toThrow();，您应该 await 完成 expect 块，从而导致：

describe("login function", () => {
    let mock;

    beforeEach(() => {
        mock = new MockAdapter(axios);
        localStorage.clear();
    });

    afterEach(() => {
        // We need to clear mocks
        // and remove tokens from local storage to prevent
        // us from staying logged in
        mock.restore();
    });

    test("Check that exception thrown on server error", async () => {
        // Mock loggedin function to throw error
        mock.onPost().reply(500);
        Test that error is uncaught.
        await expect(() => auth.login("test@example.com", "pass")).rejects.toThrow(); // add an error message to check for correct error
    });
});

PS。这在 jest API docs.

中有详细记录

是否可以在节点中为没有 catch 块的承诺编写一个笑话单元测试？

Is it possible to write a jest unit test in node for a promise with no catch block?

unit-testing

node.js

reactjs

jestjs

redux-saga