gistfile1.js

    // Sign a user in
    signin: function (user, callback) {

      var self = this,
          attributes = { 'sessionId': 'foobar' };

      if (typeof(user) == 'function') {
        callback = user;
      }
      else if (typeof(user) == 'object') {
        this.user = user;
      }

      if (typeof callback != 'function') {
        throw new Error('Signing in needs a callback!');
      }

      if (!this.user.api_id) {
        throw new Error('Need an API ID to signin a user');
      }

      attributes.user = apiUsers[this.user.api_id];
      attributes.user.orgs = [{
        orgName: 'testOrg',
        title: 'testOrgs',
        id: '123'
      }];

      sinon.stub(api.User.prototype, 'signin')
        .yieldsTo('success', attributes);

      sinon.stub(api.User.prototype, 'fetch')
        .yieldsTo('success', new api.User(attributes), attributes);

      this.request('post', '/signin')
        .send(this.user)
        .expect(200)
        .end(function (err, res) {
          (err === null).should.be.true;
          api.User.prototype.signin.restore();
          api.User.prototype.fetch.restore();
          callback(err, res);
        });
    },