开玩笑的URL.createObjectURL不是一个函数 [英] Jest URL.createObjectURL is not a function

问题描述

我正在开发一个reactJs应用程序.我正在开玩笑地测试我的应用程序. 我想测试下载blob的函数.

I'm developping a reactJs application. I'm using jest to test my application. I want to test a function that download a blob.

但是不幸的是我收到了这个错误:

But unfortunately I receve this error:

URL.createObjectURL不是函数

URL.createObjectURL is not a function

我的测试功能:

describe('download', () => {
    const documentIntial = { content: 'aaa' };
    it('msSaveOrOpenBlob should not have been called when navigao is undefined', () => {
      window.navigator.msSaveOrOpenBlob = null;
      download(documentIntial);
      expect(window.navigator.msSaveOrOpenBlob).toHaveBeenCalledTimes(0);
    });
  });

我要测试的功能:

export const download = document => {
  const blob = new Blob([base64ToArrayBuffer(document.content)], {
    type: 'application/pdf',
  });
  if (window.navigator && window.navigator.msSaveOrOpenBlob) {
    window.navigator.msSaveOrOpenBlob(blob);
    return;
  }

  const fileURL = URL.createObjectURL(blob);
  window.open(fileURL);
};

推荐答案

这似乎很简单，就像在Jest中的Global上设置URL一样.像

This would appear to be as simple as setting up URL on the Global in Jest. Something like

describe('download', () => {
  const documentIntial = { content: 'aaa' };
  global.URL.createObjectURL = jest.fn();
  it('msSaveOrOpenBlob should not have been called when navigao is undefined', () => {
    global.URL.createObjectURL = jest.fn(() => 'details');
window.navigator.msSaveOrOpenBlob = jest.fn(() => 'details');
download(documentIntial);
expect(window.navigator.msSaveOrOpenBlob).toHaveBeenCalledTimes(1);
  });
});

这应该导致测试，也可以用来检查是否调用了global.URL.createObjectURL.附带说明:您可能还会遇到window.open的类似问题，如果情况如此，我建议您也进行模拟.

This should result in a test that you can also use for checking if global.URL.createObjectURL was called. As a side note: you may also run into a similar issue with window.open I would suggest mocking that as well if this becomes the case.

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