处理承诺异常的问题

Question

大家好，我正在尝试使用 Javascript 解决问题陈述，该陈述具有一个简单的按钮，可以在其 onclick 中将电影添加到收藏夹。如果电影已经被添加到收藏夹中，该函数应该抛出一个Promise.reject()。

因此，addFavourite() 有一些测试用例，并且一些测试用例失败了。你能告诉我为什么吗？我无法更改测试文件，所以我应该在我的代码中更改什么来解决错误？

这是我的addFavourite() 函数。 （注意：allMovies 是所有电影对象的列表）：

function addFavourite(searchId) {
  var favMovie = [];
  allMovies.forEach((iterator) => {
    if (iterator.id == searchId) {
      favMovie = iterator;
    }
  });
  var movieRepeated = false;
  allFavourites.forEach((iterator) => {
    if (iterator.id == favMovie.id) {
      movieRepeated = true;
    }
  });
  if (movieRepeated) {
    return Promise.reject(new Error("Movie repeated!")).then(
      resolved,
      rejected
    );
  } else {
    fetch("http://localhost:3000/favourites", {
      method: "POST",
      headers: {
        "content-type": "application/json",
      },
      body: JSON.stringify(favMovie),
    })
      .then((response) => {
        if (response.ok) {
          return response.json();
        }
      })
      .then((addedMovie) => {
        allFavourites.push(addedMovie);
        displayFavs(allFavourites);
        return allFavourites;
      });
  }
}

这些是失败的测试用例：

1.

it('adding of same movie as favourite twice shall be restricted', (done) => {
        fetchMock.get('http://localhost:3000/movies', moviesTestData);
        fetchMock.get('http://localhost:3000/favourites', favouritesTestData);
        fetchMock.post('http://localhost:3000/favourites', moviesTestData[0]);

        script.getMovies()
        .then(() => {
            return script.getFavourites();
        })
        .then(() => {
            return script.addFavourite(476307);
        })
        .catch((err) => {
            expect(err).to.not.equal(null, err);
            expect(err.message).to.equal('Movie is already added to favourites');
            done();
        });
    });

it(`addFavourites() shall hit the correct api with correct data and 
        return correct response`, (done) => {
            fetchMock.get('http://localhost:3000/movies', moviesTestData);
            fetchMock.get('http://localhost:3000/favourites', favouritesTestData);
            fetchMock.post('http://localhost:3000/favourites', moviesTestData[0]);

            script.getMovies()
            .then(() => {
                return script.getFavourites();
            })
            .then(() => {
                return script.addFavourite(476307);
            })
            .then((res) => {
                const lastCallArgs = fetchMock.lastCall();
                expect(lastCallArgs[0]).to.equal('http://localhost:3000/favourites');
                expect(lastCallArgs[1].method).to.equal('POST');
                expect(lastCallArgs[1].body).to.equal(JSON.stringify(moviesTestData[0]));
                favouritesTestData.push(moviesTestData[0]);
                expect(res).to.deep.equal(favouritesTestData);
                expect(document.getElementById('favouritesList').innerHTML)
                .to.include('The Unique Lama');
                done();
            })
            .catch((err) => {
                expect(err).to.equal(null, err);
                done();
            });
    });

这是我得到的错误：

addFavourites() shall hit the correct api with correct data and return correct response:
Error: Timeout of 2000ms exceeded. For async tests and hooks, ensure "done()" is called; if returning a Promise, ensure it resolves. 
      at listOnTimeout (internal/timers.js:554:17)
      at processTimers (internal/timers.js:497:7)

Answer 1

您可能还需要在 then 主体中调用 done()，因为您没有向测试运行器返回承诺。