开玩笑地测试Blob返回

Question

如何在Jest中测试以下功能？

 export async function getPdfFile() {
  try {
    const res = await fetch(SOME_URL_TO_PDF);
    const blob = await res.blob();
    return blob;
  } catch ( error ) {
    throw new Error( 'ERROR' );
  }
}

到目前为止，我已经设法编写了以下测试，但是由于响应无法匹配，因此无法正常工作：

  import {getPdfFile} from "../../services/PdfService";

  const response = {Blob: 'test.pdf'};

  describe('Testing the download service', () => {
    it( 'Function returns a correct result', async () => {
      fetchMock.mock( `${SOME_URL_TO_PDF}`, response );
      expect( await getPdfFile() ).toEqual( 'test.pdf' );
    });
  });