How to test file upload service response - javascript

Question

I hope you are well, thank you in advance. I need help to test the code of my service POST file upload I have tried everything and does not give me, I attach code of the service and the tests that I try to do.

The functionality is simply a file uploader that sends it to a POST service, the service should respond this: RESPONDE 200:

{
    "file_name": "12582_c7282234-4ad1-4f02-afde-a33f69401458.pdf",
    "original_file_name": "CONSTANCIA DEVOLUCION DINERO.pdf",
    "type": "application/pdf",
    "size": 182978,
    "creation_date": "2022-02-24T20:24:59.372916"
} 

Code:

import * as fs from 'fs';
import FormData from 'form-data';

upload(files: any) {

    console.log('llega esto', files);

    return new Promise((resolve, reject) => {
        const formData = new FormData();
        const readFile = fs.createReadStream(files.file[0].path);
        readFile.on('open', () => {
            formData.append('file', readFile, files.file[0].originalFilename);

            const url = `${this.baseUrl}/attachments`;

            const headers = {
                'x-caller-id': '12582',
                'Content-Type': 'application/json',
                ...formData.getHeaders(),
            };
            console.log('antes de requets');

            return this.request
                .post(url, {
                    data: formData,
                    headers: headers,
                    context: this.context,
                })
                .then((response: Response<any>) => {
                    resolve(response);
                })
                .catch((error: Error) => {
                    reject(error);
                });
        });
    });
}

CODE TEST POSITIVE

test('you should not send the file', () => {
    const responseUpload = {
      file_name: 'file.pdf',
      original_file_name: 'file.pdf',
      type: 'application/pdf',
      size: 0.0000076294,
      creation_date: '2022-02-24T20:24:59.372916',
    };
    const pathFile = 'tests/unit/services/utils/mockFile.pdf';

    fs.writeFile(pathFile, 'New file test', function (err) {
      if (err) throw err;
    });

    const files = {
      file: [
        {
          fieldName: 'file',
          originalFilename: 'file.pdf',
          path: 'tests/unit/services/utils/mockFile.pdf',
          headers: [Object],
          size: 8,
        },
      ],
    };
    return new Promise((resolve) => {
      const readFile = fs.createReadStream(files.file[0].path);

      const formData = new FormData();
      readFile.on('open', () => {
        formData.append('file', readFile, files.file[0].originalFilename);

        new Service(req).upload(files).then((response) => {
          resolve(response);
          expect(response).toBe(responseUpload);
          
        });
      });
      fs.unlink(pathFile, () => ({}));
    });
  });
});

I get a 404 or that it cannot read the file

TEST NEGATIVE

const pathFile = 'tests/unit/services/utils/mockFile.pdf';
fs.writeFile(pathFile, 'New file test', function(err) {
    if (err) throw err;
});
const files = {
    file: [
        {
            path: 'mockFile.pdf',
            originalFilename: 'mockFile.pdf',
            size: 0.0000076294,
        },
    ],
};
new Service(req).upload(files).catch((error) => {
    expect(error.status).toBe(404);
});
fs.unlink(pathFile, () => ({}));

error test negative

**FAIL   services  tests/unit/services/upload/index.spec.ts
● Test suite failed to run**
    
Jest worker encountered 4 child process exceptions, exceeding retry limit