How to test/simulate file upload from nodeJs unit/integration test?

I would like to test my GraphQL endpoint, for that I created a test client based on request-promise-native. This works for all mutations, but not when it has an Upload type. I studied the unit testing code in this library, but could not figure it out.

I want to programatically upload a file and send it with form data. My current solution always has a file value of null on the receiving side.

Preparing the file for formData:

const file: any = fs.createReadStream('./a.txt');
const f = Promise.resolve({
      stream: file,
      filename: 'a.txt',
      mimetype: 'application/pdf',
      encoding: '7bit',
    });

In my formData (the query and variables are inserted before, but that is not the problem

const formData: any = {
      operations: `{ "query": "${query}", ${variables} }`,
      map: '{ "file0": ["variables.file"] }',
      file0: {
        value: f,
        options: {
          filename: 'a.txt',
          contentType: 'application/txt',
        },
      },
    };

Please help!

[awilderink]

@dionnyprensa I created a little helper for this to use in my tests:

import { contentType } from 'mime-types'
import { extname } from 'path';
import app from '@/app'
import * as supertest from 'supertest'

const graphql = (query: string, variables: { [x: string]: any } = {}) => {
  const map = Object.assign({}, Object.keys(variables).map(key => [`variables.${key}`]));
  const request = supertest(app)
    .post('/graphql')
    .field('operations', JSON.stringify({ query }))
    .field('map', JSON.stringify(map));

  Object.values(variables).forEach((value, i) => {
    if (contentType(extname(value))) {
      request.attach(`${i}`, value);
    } else {
      request.field(`${i}`, value);
    }
  });

  return request;
};

describe('Upload', () => {
  it('should return a file after uploading one', async done => {
    const res = await graphql(
      /* GraphQL */ `
        mutation($file: Upload!) {
          singleFileUpload(file: $file) {
            id
          }
        }
      `,
      { file: __dirname + '/__files/image.jpg' }
    )
    expect(res.body.data.singleFileUpload.id).toBeDefined()
    done()
  })
})

I use it together with apollo-server-express and Jest, but I think it might work for you aswell. It may even work with regular queries, but I haven’t tested that yet.

[jaydenseric]

You can find inspiration in the tests: https://github.com/jaydenseric/graphql-upload/blob/8d0f3e5ad144ab15eb7449e53322627eaed1d541/src/test.mjs#L77

You should only need node-fetch and form-data:

const FormData = require('form-data')
const fetch = require('node-fetch')

const body = new FormData()

body.append(
  'operations',
  JSON.stringify({
    query: /* GraphQL */ `
      mutation($file: Upload!) {
        uploadFile(file: $file) {
          id
        }
      }
    `,
    variables: {
      file: null
    }
  })
)
body.append('map', JSON.stringify({ 1: ['variables.file'] }))
body.append('1', 'a', { filename: 'a.txt' })

const response = fetch('http://localhost:3001', { method: 'POST', body })

I find it easier to create files in the test itself rather than use fs:

- body.append('1', 'a', { filename: 'a.txt' })
+ body.append('1', fs.createReadStream('./a.txt'))