Loopback testing with supertest, mocha and models - node.js

Question

On the Google groups post on deprecating loopback-testing there is a question that asks about providing a proper example of how testing can be achieved without loopback-testing. That thread talks about using supertest instead.
Below is an attempt that I made to combine Mocha, supertest along with models (from app.js). The result works really well when I run the file by itself. But if I had another test file (say test-teacher.js) then the first test file (call it test-student.js) starts to fail in weird ways I can't describe.
Am I missing something or can models not be used like I am using them below?
describe('/Student', function () {
var server = require('../server/server')
var loopback = require('loopback')
var supertest = require('supertest')
var request = require('supertest')(server)
var dataSource = server.dataSource('db', {adapter: 'memory'})
var Student = dataSource.define('Student', {
'id': Number,
'points': Number
});
beforeEach(function () {
Student.updateOrCreate({id: 1, points: 5000});
})
it('Post a new student', function (done) {
request.post('/api/Students').send({points: 5000}).expect(200, done)
})
})

Answer 1

Based on feedback from jakerella on the previous answer, I changed the code above so that I don't have to redefine the models from scratch in the code (thanks jakerella!)
With the code below, I am able to run all the tests from multiple different models as a single suite using npm test without any failures.
Since I am interested in only individual orders ... listen and close were not necessary. I suspect that if I was testing overall instances of models that were created it would become required.
describe('/Student', function () {
var server = require('../server/server')
var request = require('supertest')(server)
var expect = require('expect.js')
var Student
before(function() {
Student = server.models.Student
})
beforeEach(function (done) {
Student.upsert({id: 1, points: 5000}, function() { done() })
})
it('Post a new student', function (done) {
request.post('/api/Students').send({points: 5000}).expect(200, done)
})
})

Answer 2

Wanted to toss this into an answer... the first issue was an undefined dataSource var, but then you also had redefined Student in your two tests. My recommendation instead is used the LoopBack app and models already defined (usually in common/models/).Then the basic implementation for testing (that I use) is something like the code below (using mocha and chai). Note the beforeEach and afterEach to start and stop the server.
var assert = require('chai').assert,
superagent = require('superagent'),
app = require('../server/server');
describe('Person model', function() {
var server;
beforeEach(function(done) {
server = app.listen(done);
});
afterEach(function(done) {
server.close(done);
});
it('should log in and log out with live server', function(done) {
superagent
.post('http://localhost:3000/api/People/login')
.send({ email: 'john#doe.com', password: 'foobar' })
.set('Accept', 'application/json')
.set('Content-Type', 'application/json')
.end(function(err, loginRes) {
if (err) { return done(err); }
assert.equal(loginRes.status, 200);
assert.ok(loginRes.body);
assert.equal(loginRes.body.userId, 1);
}
});
});
});