Avoiding Mocha timeout on assertion error with SuperTest?

Question

I have some Sails.js API tests (using Mocha) that make use of SuperTest's .end() method to run some Chai assertions on the response.

I call the test's done() callback after the assertions, but if an assertion error is thrown, the test times out.

I can wrap the assertions in a try/finally, but this seems a bit icky:

var expect = require('chai').expect;
var request = require('supertest');

// ...

describe('should list all tasks that the user is authorized to view', function () {

  it('the admin user should be able to see all tasks', function (done) {
    var agent = request.agent(sails.hooks.http.app);
    agent
      .post('/login')
      .send(userFixtures.admin())
      .end(function (err, res) {
        agent
          .get('/api/tasks')
          .expect(200)
          .end(function (err, res) {
            try {
              var tasks = res.body;
              expect(err).to.not.exist;
              expect(tasks).to.be.an('array');
              expect(tasks).to.have.length.of(2);
            } finally {
              done(err);
            }
          });
      });
  });
});

Any suggestions on how to better deal with this? Perhaps Chai HTTP might be better?

score 1 · Answer 1 · answered Feb 26 '15 at 21:35

According to Supertest's documentation, you need to check for the presence of err and, if it exists, pass it to the done function. Like so

.end(function (err, res) {
    if (err) return done(err);

    // Any other response-related assertions here
    ...

    // Finish the test
    done();
});

score 1 · Answer 2 · answered Feb 27 '15 at 18:01

You can pass out login logic from test.

// auth.js
var request = require('supertest'),
    agent = request.agent;

exports.login = function(done) {
    var loggedInAgent = agent(sails.hooks.http.app);
    loggedInAgent
        .post('/login')
        .send(userFixtures.admin())
        .end(function (err, res) {
            loggedInAgent.saveCookies(res);
            done(loggedInAgent);
        });
};

And then just use it in your test:

describe('should list all tasks that the user is authorized to view', function () {

    var admin;

    before(function(done) {
        // do not forget to require this auth module
        auth.login(function(loggedInAgent) {
            admin = loggedInAgent;
            done();
        });
    });

    it('the admin user should be able to see all tasks', function (done) {

        admin
            .get('/api/tasks')
            .expect(function(res) 
                var tasks = res.body;
                expect(tasks).to.be.an('array');
                expect(tasks).to.have.length.of(2);
            })
            .end(done);

    });

    it('should have HTTP status 200', function() {

        admin
            .get('/api/tasks')
            .expect(200, done);

    });

});

With such approach you should not login your admin for each test (you can reuse your admin again and again in your describe block), and your test cases become more readable.

You should not get timeouts with this approach because .end(done) guaranties that your test will finish without errors as well with them.

Avoiding Mocha timeout on assertion error with SuperTest?

2 Answers2