Question

I have an app built on Express.js and I’d like to test the file upload functionality. I’m trying to reproduce the object parsed to req.files (when using express.bodyParser middleware). How can I do this?

Answer 1

You can do this directly in Mocha but it’s a bit tricky. Here’s an example posting an image:

var filename = 'x.png'
  , boundary = Math.random()

request(app)
  .post('/g/' + myDraftGallery._id)
  .set('Content-Type', 'multipart/form-data; boundary=' + boundary)
  .write('--' + boundary + '\r\n')
  .write('Content-Disposition: form-data; name="image"; filename="'+filename+'"\r\n')
  .write('Content-Type: image/png\r\n')
  .write('\r\n')
  .write(fs.readFileSync('test/'+filename))
  .write('\r\n--' + boundary + '--')
  .end(function(res){
    res.should.have.status(200)
    done()
  })

The name parameter of Content-Disposition is what your file will be accessible as via req.files (so req.files.image for my example)
You can also use an array value like this: name=”images[]” and your file(s) will be available via an array, e.g: req.files.images[0]

Also if you’re not already using it you should have a look at this (makes mocha/express testing a ~bit~ easier):
https://github.com/visionmedia/express/blob/master/test/support/http.js

Edit: Since express 3-beta5, express uses supertest. To look at the old http.js code look here: https://github.com/visionmedia/express/blob/3.0.0beta4/test/support/http.js
Or simply move over to supertest..