Demonstration of problems with hasManyThrough relations and the relation.findOne helper

hasManyThroughProblems.js

// mocha hasManyThroughProblems.js

var app = require('loopback/test/fixtures/simple-integration-app/server/server.js');
var expect = require('chai').expect;

describe('relation check', function() {

  before(function defineProductAndCategoryModels() {
    var product = app.model(
      'product',
      { properties: { id: 'string', name: 'string' }, dataSource: 'db' }
    );

    var category = app.model(
      'category',
      { properties: { id: 'string', name: 'string' }, dataSource: 'db' }
    );

    var connector = app.model(
      'connector',
      { properties: { id: 'string' }, dataSource: 'db' }
    );

    product.hasAndBelongsToMany(category, { through: connector });
    category.hasMany(product, { through: connector });
  });

  var testCategory;
  before(function initializeCategory(done) {
    app.models.category.create({ name: 'my-category' }, function (err, instance) {
      if (err) return done(err);
      testCategory = instance;
      done();
    });
  });

  before(function initializeProduct(done) {
    testCategory.products.create({ name: 'a-product' }, done);
  });

  it('should be possible to findOne on the relation and get back a product', function (done) {
    testCategory.products.findOne(function (err, p) {
      if (err) return done(err);
      expect(p).to.be.ok();
      expect(p).to.be.an.instanceof(app.models.product);
      done();
    });
  });
});