How to use Mocha and Supertest to send malformed JSON?

I have the current test I want to run:

var request = require('supertest');

it('should be malformed json', function(done) {
  request(config.base)
    .post('/authenticate')
    .send('{"project":{"description":\'test"}}')
    .set('Authorization', 'Bearer ' + config.token)
    .expect('Content-Type', /json/)
    .expect(status.BAD_REQUEST);
});

However, supertest seems to validate it, and it just sends '{}' in the body. Any idea how I can get around this?

Solution

You are passing a string to the send method, so it will be sent to the server as is (you could write anything there!).

Once the server receives the string, it parses the JSON and it finds the error. What happens next depend on how the server application is configured (or the framework you're using). It is possible that in this case the server just ignores any malformed JSON input, and thus it's like you called /authenticate without any input.

TL;DR: send() just sends any string you pass it. If you want to raise an error, you need to modify the server, and not the test suite.

EDIT

I did some more digging. First of all, as I said before, send() indeed leaves strings as is. You can see it from the code: https://github.com/visionmedia/superagent/blob/master/lib/client.js#L778

Thus said, you did not tell the server that the request body was in JSON format, so what you're saying is interpreted as "text/plain" and not parsed. To pass a manual JSON string to send() you also need to specify the content-type of the request:

request(config.base)
    .post('/authenticate')
    .type('json')
    .send('{"project":{"description":\'test"}}')
//...