loopback-datasource-juggler/test/relations.test.js

// This test written in mocha+should.js
var should = require('./init.js');

var db, Book, Chapter, Author, Reader;
var Category, Product;
var Picture, PictureLink;
var Person, Address;
var Link;

describe('relations', function () {

  describe('hasMany', function () {
    before(function (done) {
      db = getSchema();
      Book = db.define('Book', {name: String, type: String});
      Chapter = db.define('Chapter', {name: {type: String, index: true},
        bookType: String});
      Author = db.define('Author', {name: String});
      Reader = db.define('Reader', {name: String});

      db.automigrate(function () {
        Book.destroyAll(function () {
          Chapter.destroyAll(function () {
            Author.destroyAll(function () {
              Reader.destroyAll(done);
            });
          });
        });
      });
    });

    it('can be declared in different ways', function (done) {
      Book.hasMany(Chapter);
      Book.hasMany(Reader, {as: 'users'});
      Book.hasMany(Author, {foreignKey: 'projectId'});
      var b = new Book;
      b.chapters.should.be.an.instanceOf(Function);
      b.users.should.be.an.instanceOf(Function);
      b.authors.should.be.an.instanceOf(Function);
      Object.keys((new Chapter).toObject()).should.include('bookId');
      Object.keys((new Author).toObject()).should.include('projectId');

      db.automigrate(done);
    });

    it('can be declared in short form', function (done) {
      Author.hasMany('readers');
      (new Author).readers.should.be.an.instanceOf(Function);
      Object.keys((new Reader).toObject()).should.include('authorId');

      db.autoupdate(done);
    });

    it('should build record on scope', function (done) {
      Book.create(function (err, book) {
        var c = book.chapters.build();
        c.bookId.should.equal(book.id);
        c.save(done);
      });
    });

    it('should create record on scope', function (done) {
      Book.create(function (err, book) {
        book.chapters.create(function (err, c) {
          should.not.exist(err);
          should.exist(c);
          c.bookId.should.equal(book.id);
          done();
        });
      });
    });

    it('should fetch all scoped instances', function (done) {
      Book.create(function (err, book) {
        book.chapters.create({name: 'a'}, function () {
          book.chapters.create({name: 'z'}, function () {
            book.chapters.create({name: 'c'}, function () {
              verify(book);
            });
          });
        });
      });
      function verify(book) {
        book.chapters(function (err, ch) {
          should.not.exist(err);
          should.exist(ch);
          ch.should.have.lengthOf(3);

          book.chapters({order: 'name DESC'}, function (e, c) {
            should.not.exist(e);
            should.exist(c);
            c.shift().name.should.equal('z');
            c.pop().name.should.equal('a');
            done();
          });
        });
      }
    });

    it('should find scoped record', function (done) {
      var id;
      Book.create(function (err, book) {
        book.chapters.create({name: 'a'}, function (err, ch) {
          id = ch.id;
          book.chapters.create({name: 'z'}, function () {
            book.chapters.create({name: 'c'}, function () {
              verify(book);
            });
          });
        });
      });

      function verify(book) {
        book.chapters.findById(id, function (err, ch) {
          should.not.exist(err);
          should.exist(ch);
          ch.id.should.eql(id);
          done();
        });
      }
    });

    it('should set targetClass on scope property', function() {
      should.equal(Book.prototype.chapters._targetClass, 'Chapter');
    });

    it('should update scoped record', function (done) {
      var id;
      Book.create(function (err, book) {
        book.chapters.create({name: 'a'}, function (err, ch) {
          id = ch.id;
          book.chapters.updateById(id, {name: 'aa'}, function(err, ch) {
            verify(book);
          });
        });
      });

      function verify(book) {
        book.chapters.findById(id, function (err, ch) {
          should.not.exist(err);
          should.exist(ch);
          ch.id.should.eql(id);
          ch.name.should.equal('aa');
          done();
        });
      }
    });

    it('should destroy scoped record', function (done) {
      var id;
      Book.create(function (err, book) {
        book.chapters.create({name: 'a'}, function (err, ch) {
          id = ch.id;
          book.chapters.destroy(id, function(err, ch) {
            verify(book);
          });
        });
      });

      function verify(book) {
        book.chapters.findById(id, function (err, ch) {
          should.exist(err);
          done();
        });
      }
    });

    it('should check existence of a scoped record', function (done) {
      var id;
      Book.create(function (err, book) {
        book.chapters.create({name: 'a'}, function (err, ch) {
          id = ch.id;
          book.chapters.create({name: 'z'}, function () {
            book.chapters.create({name: 'c'}, function () {
              verify(book);
            });
          });
        });
      });

      function verify(book) {
        book.chapters.exists(id, function (err, flag) {
          should.not.exist(err);
          flag.should.be.eql(true);
          done();
        });
      }
    });
  });

  describe('hasMany through', function () {
    var Physician, Patient, Appointment;

    before(function (done) {
      db = getSchema();
      Physician = db.define('Physician', {name: String});
      Patient = db.define('Patient', {name: String});
      Appointment = db.define('Appointment', {date: {type: Date,
        default: function () {
          return new Date();
        }}});

      Physician.hasMany(Patient, {through: Appointment});
      Patient.hasMany(Physician, {through: Appointment});
      Appointment.belongsTo(Patient);
      Appointment.belongsTo(Physician);

      db.automigrate(['Physician', 'Patient', 'Appointment'], function (err) {
        done(err);
      });
    });

    it('should build record on scope', function (done) {
      Physician.create(function (err, physician) {
        var patient = physician.patients.build();
        patient.physicianId.should.equal(physician.id);
        patient.save(done);
      });
    });

    it('should create record on scope', function (done) {
      Physician.create(function (err, physician) {
        physician.patients.create(function (err, patient) {
          should.not.exist(err);
          should.exist(patient);
          Appointment.find({where: {physicianId: physician.id, patientId: patient.id}},
            function(err, apps) {
              should.not.exist(err);
              apps.should.have.lengthOf(1);
              done();
          });
        });
      });
    });

    it('should fetch all scoped instances', function (done) {
      Physician.create(function (err, physician) {
        physician.patients.create({name: 'a'}, function () {
          physician.patients.create({name: 'z'}, function () {
            physician.patients.create({name: 'c'}, function () {
              verify(physician);
            });
          });
        });
      });
      function verify(physician) {
        physician.patients(function (err, ch) {
          should.not.exist(err);
          should.exist(ch);
          ch.should.have.lengthOf(3);
          done();
        });
      }
    });

    it('should find scoped record', function (done) {
      var id;
      Physician.create(function (err, physician) {
        physician.patients.create({name: 'a'}, function (err, ch) {
          id = ch.id;
          physician.patients.create({name: 'z'}, function () {
            physician.patients.create({name: 'c'}, function () {
              verify(physician);
            });
          });
        });
      });

      function verify(physician) {
        physician.patients.findById(id, function (err, ch) {
          should.not.exist(err);
          should.exist(ch);
          ch.id.should.equal(id);
          done();
        });
      }
    });

    it('should allow to use include syntax on related data', function (done) {
      var Address = db.define('Address', {name: String});
      Patient.belongsTo(Address);
      Physician.create(function (err, physician) {
        physician.patients.create({name: 'a'}, function (err, patient) {
          Address.create({name: 'z'}, function (err, address) {
            patient.address(address);
            patient.save(function() {
              verify(physician);
            });
          });
        });
      });
      function verify(physician) {
        physician.patients({include: 'address'}, function (err, ch) {
          should.not.exist(err);
          should.exist(ch);
          ch.should.have.lengthOf(1);
          ch[0].addressId.should.equal(1);
          var address = ch[0].address();
          should.exist(address);
          address.should.be.an.instanceof(Address);
          address.name.should.equal('z');
          done();
        });
      }
    });

    it('should set targetClass on scope property', function() {
      should.equal(Physician.prototype.patients._targetClass, 'Patient');
    });

    it('should update scoped record', function (done) {
      var id;
      Physician.create(function (err, physician) {
        physician.patients.create({name: 'a'}, function (err, ch) {
          id = ch.id;
          physician.patients.updateById(id, {name: 'aa'}, function(err, ch) {
            verify(physician);
          });
        });
      });

      function verify(physician) {
        physician.patients.findById(id, function (err, ch) {
          should.not.exist(err);
          should.exist(ch);
          ch.id.should.equal(id);
          ch.name.should.equal('aa');
          done();
        });
      }
    });

    it('should destroy scoped record', function (done) {
      var id;
      Physician.create(function (err, physician) {
        physician.patients.create({name: 'a'}, function (err, ch) {
          id = ch.id;
          physician.patients.destroy(id, function(err, ch) {
            verify(physician);
          });
        });
      });

      function verify(physician) {
        physician.patients.findById(id, function (err, ch) {
          should.exist(err);
          done();
        });
      }
    });

    it('should check existence of a scoped record', function (done) {
      var id;
      Physician.create(function (err, physician) {
        physician.patients.create({name: 'a'}, function (err, ch) {
          id = ch.id;
          physician.patients.create({name: 'z'}, function () {
            physician.patients.create({name: 'c'}, function () {
              verify(physician);
            });
          });
        });
      });

      function verify(physician) {
        physician.patients.exists(id, function (err, flag) {
          should.not.exist(err);
          flag.should.be.eql(true);
          done();
        });
      }
    });

    it('should allow to add connection with instance', function (done) {
      Physician.create({name: 'ph1'}, function (e, physician) {
        Patient.create({name: 'pa1'}, function (e, patient) {
          physician.patients.add(patient, function (e, app) {
            should.not.exist(e);
            should.exist(app);
            app.should.be.an.instanceOf(Appointment);
            app.physicianId.should.equal(physician.id);
            app.patientId.should.equal(patient.id);
            done();
          });
        });
      });
    });

    it('should allow to remove connection with instance', function (done) {
      var id;
      Physician.create(function (err, physician) {
        physician.patients.create({name: 'a'}, function (err, patient) {
          id = patient.id;
          physician.patients.remove(id, function (err, ch) {
            verify(physician);
          });
        });
      });

      function verify(physician) {
        physician.patients.exists(id, function (err, flag) {
          should.not.exist(err);
          flag.should.be.eql(false);
          done();
        });
      }
    });

    beforeEach(function (done) {
      Appointment.destroyAll(function (err) {
        Physician.destroyAll(function (err) {
          Patient.destroyAll(done);
        });
      });
    });

  });
  
  describe('hasMany with properties', function () {
    it('can be declared with properties', function (done) {
      Book.hasMany(Chapter, { properties: { type: 'bookType' } });
      db.automigrate(done);
    });
    
    it('should create record on scope', function (done) {
      Book.create({ type: 'fiction' }, function (err, book) {
        book.chapters.create(function (err, c) {
          should.not.exist(err);
          should.exist(c);
          c.bookId.should.equal(book.id);
          c.bookType.should.equal('fiction');
          done();
        });
      });
    });
  });

  describe('hasMany with scope and properties', function () {
    it('can be declared with properties', function (done) {
      db = getSchema();
      Category = db.define('Category', {name: String, productType: String});
      Product = db.define('Product', {name: String, type: String});

      Category.hasMany(Product, {
        properties: function(inst) {
          if (!inst.productType) return; // skip
          return { type: inst.productType };
        },
        scope: function(inst, filter) {
          var m = this.properties(inst); // re-use properties
          if (m) return { where: m };
        }
      });
      db.automigrate(done);
    });
    
    it('should create record on scope', function (done) {
      Category.create(function (err, c) {
        c.products.create({ type: 'book' }, function(err, p) {
          p.categoryId.should.equal(c.id);
          p.type.should.equal('book');
          c.products.create({ type: 'widget' }, function(err, p) {
            p.categoryId.should.equal(c.id);
            p.type.should.equal('widget');
            done();
          });
        });
      });
    });
    
    it('should find records on scope', function (done) {
      Category.findOne(function (err, c) {
        c.products(function(err, products) {
          products.should.have.length(2);
          done();
        });
      });
    });
    
    it('should find record on scope - filtered', function (done) {
      Category.findOne(function (err, c) {
        c.products({ where: { type: 'book' } }, function(err, products) {
          products.should.have.length(1);
          products[0].type.should.equal('book');
          done();
        });
      });
    });
    
    // So why not just do the above? In LoopBack, the context
    // that gets passed into a beforeRemote handler contains
    // a reference to the parent scope/instance: ctx.instance
    // in order to enforce a (dynamic scope) at runtime
    // a temporary property can be set in the beforeRemoting
    // handler. Optionally,properties dynamic properties can be declared.
    //
    // The code below simulates this.
    
    it('should create record on scope - properties', function (done) {
      Category.findOne(function (err, c) {
        c.productType = 'tool'; // temporary
        c.products.create(function(err, p) {
          p.categoryId.should.equal(c.id);
          p.type.should.equal('tool');
          done();
        });
      });
    });
    
    it('should find records on scope', function (done) {
      Category.findOne(function (err, c) {
        c.products(function(err, products) {
          products.should.have.length(3);
          done();
        });
      });
    });
    
    it('should find record on scope - scoped', function (done) {
      Category.findOne(function (err, c) {
        c.productType = 'book'; // temporary, for scoping
        c.products(function(err, products) {
          products.should.have.length(1);
          products[0].type.should.equal('book');
          done();
        });
      });
    });
    
    it('should find record on scope - scoped', function (done) {
      Category.findOne(function (err, c) {
        c.productType = 'tool'; // temporary, for scoping
        c.products(function(err, products) {
          products.should.have.length(1);
          products[0].type.should.equal('tool');
          done();
        });
      });
    });
    
    it('should delete records on scope - scoped', function (done) {
      Category.findOne(function (err, c) {
        c.productType = 'tool'; // temporary, for scoping
        c.products.destroyAll(function(err, result) {
          done();
        });
      });
    });
    
    it('should find record on scope - verify', function (done) {
      Category.findOne(function (err, c) {
        c.products(function(err, products) {
          products.should.have.length(2);
          done();
        });
      });
    });
  
  });
  
  describe('polymorphic hasOne', function () {
    before(function (done) {
      db = getSchema();
      Picture = db.define('Picture', {name: String});
      Author = db.define('Author', {name: String});
      Reader = db.define('Reader', {name: String});

      db.automigrate(function () {
        Picture.destroyAll(function () {
          Author.destroyAll(function () {
            Reader.destroyAll(done);
          });
        });
      });
    });

    it('can be declared', function (done) {
      Author.hasOne(Picture, { as: 'avatar', polymorphic: 'imageable' });
      Reader.hasOne(Picture, { as: 'mugshot', polymorphic: 'imageable' });
      Picture.belongsTo('imageable', { polymorphic: true });
      db.automigrate(done);
    });
    
    it('should create polymorphic relation - author', function (done) {
      Author.create({name: 'Author 1' }, function (err, author) {
        author.avatar.create({ name: 'Avatar' }, function (err, p) {
          should.not.exist(err);
          should.exist(p);
          p.imageableId.should.equal(author.id);
          p.imageableType.should.equal('Author');
          done();
        });
      });
    });
    
    it('should create polymorphic relation - reader', function (done) {
      Reader.create({name: 'Reader 1' }, function (err, reader) {
        reader.mugshot.create({ name: 'Mugshot' }, function (err, p) {
          should.not.exist(err);
          should.exist(p);
          p.imageableId.should.equal(reader.id);
          p.imageableType.should.equal('Reader');
          done();
        });
      });
    });
    
    it('should find polymorphic relation - author', function (done) {
      Author.findOne(function (err, author) {
        author.avatar(function (err, p) {
          should.not.exist(err);
          p.name.should.equal('Avatar');
          p.imageableId.should.eql(author.id);
          p.imageableType.should.equal('Author');
          done();
        });
      });
    });
    
    it('should find polymorphic relation - reader', function (done) {
      Reader.findOne(function (err, reader) {
        reader.mugshot(function (err, p) {
          should.not.exist(err);
          p.name.should.equal('Mugshot');
          p.imageableId.should.eql(reader.id);
          p.imageableType.should.equal('Reader');
          done();
        });
      });
    });
    
    it('should find inverse polymorphic relation - author', function (done) {
      Picture.findOne({ where: { name: 'Avatar' } }, function (err, p) {
        p.imageable(function (err, imageable) {
          should.not.exist(err);
          imageable.should.be.instanceof(Author);
          imageable.name.should.equal('Author 1');
          done();
        });
      });
    });
    
    it('should find inverse polymorphic relation - reader', function (done) {
      Picture.findOne({ where: { name: 'Mugshot' } }, function (err, p) {
        p.imageable(function (err, imageable) {
          should.not.exist(err);
          imageable.should.be.instanceof(Reader);
          imageable.name.should.equal('Reader 1');
          done();
        });
      });
    });
    
  });
  
  describe('polymorphic hasMany', function () {
    before(function (done) {
      db = getSchema();
      Picture = db.define('Picture', {name: String});
      Author = db.define('Author', {name: String});
      Reader = db.define('Reader', {name: String});

      db.automigrate(function () {
        Picture.destroyAll(function () {
          Author.destroyAll(function () {
            Reader.destroyAll(done);
          });
        });
      });
    });

    it('can be declared', function (done) {
      Author.hasMany(Picture, { polymorphic: 'imageable' });
      Reader.hasMany(Picture, { polymorphic: { // alt syntax
        as: 'imageable', foreignKey: 'imageableId',
        discriminator: 'imageableType'
      } });
      Picture.belongsTo('imageable', { polymorphic: true });
      db.automigrate(done);
    });
    
    it('should create polymorphic relation - author', function (done) {
      Author.create({ name: 'Author 1' }, function (err, author) {
        author.pictures.create({ name: 'Author Pic' }, function (err, p) {
          should.not.exist(err);
          should.exist(p);
          p.imageableId.should.eql(author.id);
          p.imageableType.should.equal('Author');
          done();
        });
      });
    });
    
    it('should create polymorphic relation - reader', function (done) {
      Reader.create({ name: 'Reader 1' }, function (err, reader) {
        reader.pictures.create({ name: 'Reader Pic' }, function (err, p) {
          should.not.exist(err);
          should.exist(p);
          p.imageableId.should.eql(reader.id);
          p.imageableType.should.equal('Reader');
          done();
        });
      });
    });
    
    it('should find polymorphic items - author', function (done) {
      Author.findOne(function (err, author) {
        author.pictures(function (err, pics) {
          should.not.exist(err);
          pics.should.have.length(1);
          pics[0].name.should.equal('Author Pic');
          done();
        });
      });
    });
    
    it('should find polymorphic items - reader', function (done) {
      Reader.findOne(function (err, reader) {
        reader.pictures(function (err, pics) {
          should.not.exist(err);
          pics.should.have.length(1);
          pics[0].name.should.equal('Reader Pic');
          done();
        });
      });
    });
    
    it('should find the inverse of polymorphic relation - author', function (done) {
      Picture.findOne({ where: { name: 'Author Pic' } }, function (err, p) {
        should.not.exist(err);
        p.imageableType.should.equal('Author');
        p.imageable(function(err, imageable) {
          should.not.exist(err);
          imageable.should.be.instanceof(Author);
          imageable.name.should.equal('Author 1');
          done();
        });
      });
    });
    
    it('should find the inverse of polymorphic relation - reader', function (done) {
      Picture.findOne({ where: { name: 'Reader Pic' } }, function (err, p) {
        should.not.exist(err);
        p.imageableType.should.equal('Reader');
        p.imageable(function(err, imageable) {
          should.not.exist(err);
          imageable.should.be.instanceof(Reader);
          imageable.name.should.equal('Reader 1');
          done();
        });
      });
    });
    
    it('should include the inverse of polymorphic relation', function (done) {
      Picture.find({ include: 'imageable' }, function (err, pics) {
        should.not.exist(err);
        pics.should.have.length(2);
        pics[0].name.should.equal('Author Pic');
        pics[0].imageable().name.should.equal('Author 1');
        pics[1].name.should.equal('Reader Pic');
        pics[1].imageable().name.should.equal('Reader 1');
        done();
      });
    });
    
    it('should assign a polymorphic relation', function(done) {
      Author.create({ name: 'Author 2' }, function(err, author) {
        var p = new Picture({ name: 'Sample' });
        p.imageable(author); // assign
        p.imageableId.should.eql(author.id);
        p.imageableType.should.equal('Author');
        p.save(done);
      });
    });
    
    it('should find polymorphic items - author', function (done) {
      Author.findOne({ where: { name: 'Author 2' } }, function (err, author) {
        author.pictures(function (err, pics) {
          should.not.exist(err);
          pics.should.have.length(1);
          pics[0].name.should.equal('Sample');
          done();
        });
      });
    });
    
    it('should find the inverse of polymorphic relation - author', function (done) {
      Picture.findOne({ where: { name: 'Sample' } }, function (err, p) {
        should.not.exist(err);
        p.imageableType.should.equal('Author');
        p.imageable(function(err, imageable) {
          should.not.exist(err);
          imageable.should.be.instanceof(Author);
          imageable.name.should.equal('Author 2');
          done();
        });
      });
    });
    
  });
  
  describe('polymorphic hasAndBelongsToMany through', function () {
    before(function (done) {
      db = getSchema();
      Picture = db.define('Picture', {name: String});
      Author = db.define('Author', {name: String});
      Reader = db.define('Reader', {name: String});
      PictureLink = db.define('PictureLink', {});

      db.automigrate(function () {
        Picture.destroyAll(function () {
          PictureLink.destroyAll(function () {
            Author.destroyAll(function () {
              Reader.destroyAll(done);
            });
          });
        });
      });
    });

    it('can be declared', function (done) {
      Author.hasAndBelongsToMany(Picture, { through: PictureLink, polymorphic: 'imageable' });
      Reader.hasAndBelongsToMany(Picture, { through: PictureLink, polymorphic: 'imageable' });
      // Optionally, define inverse relations:
      Picture.hasMany(Author, { through: PictureLink, polymorphic: 'imageable', invert: true });
      Picture.hasMany(Reader, { through: PictureLink, polymorphic: 'imageable', invert: true });
      db.automigrate(done);
    });

    var author, reader, pictures = [];
    it('should create polymorphic relation - author', function (done) {
      Author.create({ name: 'Author 1' }, function (err, a) {
        should.not.exist(err);
        author = a;
        author.pictures.create({ name: 'Author Pic 1' }, function (err, p) {
          should.not.exist(err);
          pictures.push(p);
          author.pictures.create({ name: 'Author Pic 2' }, function (err, p) {
            should.not.exist(err);
            pictures.push(p);
            done();
          });
        });
      });
    });
    
    it('should create polymorphic relation - reader', function (done) {
      Reader.create({ name: 'Reader 1' }, function (err, r) {
        should.not.exist(err);
        reader = r;
        reader.pictures.create({ name: 'Reader Pic 1' }, function (err, p) {
          should.not.exist(err);
          pictures.push(p);
          done();
        });
      });
    });
    
    it('should create polymorphic through model', function (done) {
      PictureLink.findOne(function(err, link) {
        should.not.exist(err);
        link.pictureId.should.eql(pictures[0].id); // eql for mongo ObjectId
        link.imageableId.should.eql(author.id);
        link.imageableType.should.equal('Author');
        link.imageable(function(err, imageable) {
          imageable.should.be.instanceof(Author);
          imageable.id.should.eql(author.id);
          done();
        });
      });
    });
    
    it('should get polymorphic relation through model - author', function (done) {
      Author.findById(author.id, function(err, author) {
        should.not.exist(err);
        author.name.should.equal('Author 1');
        author.pictures(function(err, pics) {
          should.not.exist(err);
          pics.should.have.length(2);
          pics[0].name.should.equal('Author Pic 1');
          pics[1].name.should.equal('Author Pic 2');
          done();
        });
      });
    });
    
    it('should get polymorphic relation through model - reader', function (done) {
      Reader.findById(reader.id, function(err, reader) {
        should.not.exist(err);
        reader.name.should.equal('Reader 1');
        reader.pictures(function(err, pics) {
          should.not.exist(err);
          pics.should.have.length(1);
          pics[0].name.should.equal('Reader Pic 1');
          done();
        });
      });
    });
    
    it('should include polymorphic items', function (done) {
      Author.find({ include: 'pictures' }, function(err, authors) {
        authors.should.have.length(1);
        authors[0].pictures(function(err, pics) {
          pics.should.have.length(2);
          pics[0].name.should.equal('Author Pic 1');
          pics[1].name.should.equal('Author Pic 2');
          done();
        });
      });
    });

    var anotherPicture;
    it('should add to a polymorphic relation - author', function (done) {
      Author.findById(author.id, function(err, author) {
        Picture.create({name: 'Example' }, function(err, p) {
          should.not.exist(err);
          pictures.push(p);
          anotherPicture = p;
          author.pictures.add(p, function(err, link) {
            link.should.be.instanceof(PictureLink);
            link.pictureId.should.eql(p.id);
            link.imageableId.should.eql(author.id);
            link.imageableType.should.equal('Author');
            done();
          });
        });
      });
    });
    
    it('should create polymorphic through model', function (done) {
      PictureLink.findOne({ where: { pictureId: anotherPicture.id, imageableType: 'Author' } }, function(err, link) {
        should.not.exist(err);
        link.pictureId.should.eql(anotherPicture.id);
        link.imageableId.should.eql(author.id);
        link.imageableType.should.equal('Author');
        done();
      });
    });

    var anotherAuthor, anotherReader;
    it('should add to a polymorphic relation - author', function (done) {
      Author.create({ name: 'Author 2' }, function (err, author) {
        should.not.exist(err);
        anotherAuthor = author;
        author.pictures.add(anotherPicture.id, function (err, p) {
          should.not.exist(err);
          done();
        });
      });
    });
    
    it('should add to a polymorphic relation - author', function (done) {
      Reader.create({name: 'Reader 2' }, function (err, reader) {
        should.not.exist(err);
        anotherReader = reader;
        reader.pictures.add(anotherPicture.id, function (err, p) {
          should.not.exist(err);
          done();
        });
      });
    });
    
    it('should get the inverse polymorphic relation - author', function (done) {
      Picture.findById(anotherPicture.id, function(err, p) {
        p.authors(function(err, authors) {
          authors.should.have.length(2);
          authors[0].name.should.equal('Author 1');
          authors[1].name.should.equal('Author 2');
          done();
        });
      });
    });
    
    it('should get the inverse polymorphic relation - reader', function (done) {
      Picture.findById(anotherPicture.id, function(err, p) {
        p.readers(function(err, readers) {
          readers.should.have.length(1);
          readers[0].name.should.equal('Reader 2');
          done();
        });
      });
    });
    
    it('should find polymorphic items - author', function (done) {
      Author.findById(author.id, function(err, author) {
        author.pictures(function(err, pics) {
          pics.should.have.length(3);
          pics[0].name.should.equal('Author Pic 1');
          pics[1].name.should.equal('Author Pic 2');
          pics[2].name.should.equal('Example');
          done();
        });
      });
    });
    
    it('should check if polymorphic relation exists - author', function (done) {
      Author.findById(author.id, function(err, author) {
        author.pictures.exists(anotherPicture.id, function(err, exists) {
          exists.should.be.true;
          done();
        });
      });
    });
    
    it('should remove from a polymorphic relation - author', function (done) {
      Author.findById(author.id, function(err, author) {
        author.pictures.remove(anotherPicture.id, function(err) {
          should.not.exist(err);
          done();
        });
      });
    });
    
    it('should find polymorphic items - author', function (done) {
      Author.findById(author.id, function(err, author) {
        author.pictures(function(err, pics) {
          pics.should.have.length(2);
          pics[0].name.should.equal('Author Pic 1');
          pics[1].name.should.equal('Author Pic 2');
          done();
        });
      });
    });
    
    it('should check if polymorphic relation exists - author', function (done) {
      Author.findById(author.id, function(err, author) {
        author.pictures.exists(7, function(err, exists) {
          exists.should.be.false;
          done();
        });
      });
    });
  
  });

  describe('belongsTo', function () {
    var List, Item, Fear, Mind;

    it('can be declared in different ways', function () {
      List = db.define('List', {name: String});
      Item = db.define('Item', {name: String});
      Fear = db.define('Fear');
      Mind = db.define('Mind');

      // syntax 1 (old)
      Item.belongsTo(List);
      Object.keys((new Item).toObject()).should.include('listId');
      (new Item).list.should.be.an.instanceOf(Function);

      // syntax 2 (new)
      Fear.belongsTo('mind');
      Object.keys((new Fear).toObject()).should.include('mindId');
      (new Fear).mind.should.be.an.instanceOf(Function);
      // (new Fear).mind.build().should.be.an.instanceOf(Mind);
    });

    it('can be used to query data', function (done) {
      List.hasMany('todos', {model: Item});
      db.automigrate(function () {
        List.create(function (e, list) {
          should.not.exist(e);
          should.exist(list);
          list.todos.create(function (err, todo) {
            todo.list(function (e, l) {
              should.not.exist(e);
              should.exist(l);
              l.should.be.an.instanceOf(List);
              todo.list().id.should.equal(l.id);
              done();
            });
          });
        });
      });
    });

    it('could accept objects when creating on scope', function (done) {
      List.create(function (e, list) {
        should.not.exist(e);
        should.exist(list);
        Item.create({list: list}, function (err, item) {
          should.not.exist(err);
          should.exist(item);
          should.exist(item.listId);
          item.listId.should.equal(list.id);
          item.__cachedRelations.list.should.equal(list);
          done();
        });
      });
    });

  });
  
  describe('belongsTo with scope', function () {
    var Person, Passport;
    
    it('can be declared with scope and properties', function (done) {
      Person = db.define('Person', {name: String, age: Number});
      Passport = db.define('Passport', {name: String, notes: String});
      Passport.belongsTo(Person, {
        properties: { notes: 'passportNotes' },
        scope: { fields: { id: true, name: true } }
      });
      db.automigrate(done);
    });

    var personCreated;
    it('should create record on scope', function (done) {
      var p = new Passport({ name: 'Passport', notes: 'Some notes...' });
      p.person.create({name: 'Fred', age: 36 }, function(err, person) {
        personCreated = person;
        p.personId.should.equal(person.id);
        p.save(function (err, p) {
          person.name.should.equal('Fred');
          person.passportNotes.should.equal('Some notes...');
          done();
        });
      });
    });
    
    it('should find record on scope', function (done) {
      Passport.findOne(function (err, p) {
        p.personId.should.eql(personCreated.id);
        p.person(function(err, person) {
          person.name.should.equal('Fred');
          person.should.not.have.property('age');
          person.should.not.have.property('passportNotes');
          done();
        });
      });
    });
  
  });

  describe('hasOne', function () {
    var Supplier, Account;

    before(function () {
      db = getSchema();
      Supplier = db.define('Supplier', {name: String});
      Account = db.define('Account', {accountNo: String, supplierName: String});
    });

    it('can be declared using hasOne method', function () {
      Supplier.hasOne(Account, { properties: { name: 'supplierName' } });
      Object.keys((new Account()).toObject()).should.include('supplierId');
      (new Supplier()).account.should.be.an.instanceOf(Function);
    });

    it('can be used to query data', function (done) {
      // Supplier.hasOne(Account);
      db.automigrate(function () {
        Supplier.create({name: 'Supplier 1'}, function (e, supplier) {
          should.not.exist(e);
          should.exist(supplier);
          supplier.account.create({accountNo: 'a01'}, function (err, account) {
            supplier.account(function (e, act) {
              should.not.exist(e);
              should.exist(act);
              act.should.be.an.instanceOf(Account);
              supplier.account().id.should.equal(act.id);
              act.supplierName.should.equal(supplier.name);
              done();
            });
          });
        });
      });
    });

    it('should set targetClass on scope property', function() {
      should.equal(Supplier.prototype.account._targetClass, 'Account');
    });
  });

  describe('hasAndBelongsToMany', function () {
    var Article, Tag, ArticleTag;
    it('can be declared', function (done) {
      Article = db.define('Article', {title: String});
      Tag = db.define('Tag', {name: String});
      Article.hasAndBelongsToMany('tags');
      ArticleTag = db.models.ArticleTag;
      db.automigrate(function () {
        Article.destroyAll(function () {
          Tag.destroyAll(function () {
            ArticleTag.destroyAll(done)
          });
        });
      });
    });

    it('should allow to create instances on scope', function (done) {
      Article.create(function (e, article) {
        article.tags.create({name: 'popular'}, function (e, t) {
          t.should.be.an.instanceOf(Tag);
          // console.log(t);
          ArticleTag.findOne(function (e, at) {
            should.exist(at);
            at.tagId.toString().should.equal(t.id.toString());
            at.articleId.toString().should.equal(article.id.toString());
            done();
          });
        });
      });
    });

    it('should allow to fetch scoped instances', function (done) {
      Article.findOne(function (e, article) {
        article.tags(function (e, tags) {
          should.not.exist(e);
          should.exist(tags);
          done();
        });
      });
    });

    it('should allow to add connection with instance', function (done) {
      Article.findOne(function (e, article) {
        Tag.create({name: 'awesome'}, function (e, tag) {
          article.tags.add(tag, function (e, at) {
            should.not.exist(e);
            should.exist(at);
            at.should.be.an.instanceOf(ArticleTag);
            at.tagId.should.equal(tag.id);
            at.articleId.should.equal(article.id);
            done();
          });
        });
      });
    });

    it('should allow to remove connection with instance', function (done) {
      Article.findOne(function (e, article) {
        article.tags(function (e, tags) {
          var len = tags.length;
          tags.should.not.be.empty;
          article.tags.remove(tags[0], function (e) {
            should.not.exist(e);
            article.tags(true, function (e, tags) {
              tags.should.have.lengthOf(len - 1);
              done();
            });
          });
        });
      });
    });

    it('should set targetClass on scope property', function() {
      should.equal(Article.prototype.tags._targetClass, 'Tag');
    });
  });
  
  describe('embedsMany', function () {
    
    var address1, address2;
    
    before(function (done) {
      db = getSchema();
      Person = db.define('Person', {name: String});
      Address = db.define('Address', {street: String});
      Address.validatesPresenceOf('street');

      db.automigrate(function () {
        Person.destroyAll(done);
      });
    });

    it('can be declared', function (done) {
      Person.embedsMany(Address);
      db.automigrate(done);
    });
    
    it('should have setup embedded accessor/scope', function() {
      var p = new Person({ name: 'Fred' });
      p.addresses.should.be.an.array;
      p.addresses.should.have.length(0);
      p.addressList.should.be.a.function;
      p.addressList.findById.should.be.a.function;
      p.addressList.updateById.should.be.a.function;
      p.addressList.destroy.should.be.a.function;
      p.addressList.exists.should.be.a.function;
      p.addressList.create.should.be.a.function;
      p.addressList.build.should.be.a.function;
    });

    it('should create embedded items on scope', function(done) {
      Person.create({ name: 'Fred' }, function(err, p) {
        p.addressList.create({ street: 'Street 1' }, function(err, address) {
          should.not.exist(err);
          address1 = address;
          should.exist(address1.id);
          address1.street.should.equal('Street 1');
          done();
        });
      });
    });
    
    it('should create embedded items on scope', function(done) {
      Person.findOne(function(err, p) {
        p.addressList.create({ street: 'Street 2' }, function(err, address) {
          should.not.exist(err);
          address2 = address;
          should.exist(address2.id);
          address2.street.should.equal('Street 2');
          done();
        });
      });
    });
    
    it('should return embedded items from scope', function(done) {
      Person.findOne(function(err, p) {
        p.addressList(function(err, addresses) {
          should.not.exist(err);
          addresses.should.have.length(2);
          addresses[0].id.should.eql(address1.id);
          addresses[0].street.should.equal('Street 1');
          addresses[1].id.should.eql(address2.id);
          addresses[1].street.should.equal('Street 2');
          done();
        });
      });
    });
    
    it('should filter embedded items on scope', function(done) {
      Person.findOne(function(err, p) {
        p.addressList({ where: { street: 'Street 2' } }, function(err, addresses) {
          should.not.exist(err);
          addresses.should.have.length(1);
          addresses[0].id.should.eql(address2.id);
          addresses[0].street.should.equal('Street 2');
          done();
        });
      });
    });
    
    it('should validate embedded items', function(done) {
      Person.findOne(function(err, p) {
        p.addressList.create({}, function(err, address) {
          should.exist(err);
          should.not.exist(address);
          err.name.should.equal('ValidationError');
          err.details.codes.street.should.eql(['presence']);
          done();
        });
      });
    });
    
    it('should find embedded items by id', function(done) {
      Person.findOne(function(err, p) {
        p.addressList.findById(address2.id, function(err, address) {
          address.should.be.instanceof(Address);
          address.id.should.eql(address2.id);
          address.street.should.equal('Street 2');
          done();
        });
      });
    });
    
    it('should check if item exists', function(done) {
      Person.findOne(function(err, p) {
        p.addressList.exists(address2.id, function(err, exists) {
          should.not.exist(err);
          exists.should.be.true;
          done();
        });
      });
    });
    
    it('should update embedded items by id', function(done) {
      Person.findOne(function(err, p) {
        p.addressList.updateById(address2.id, { street: 'New Street' }, function(err, address) {
          address.should.be.instanceof(Address);
          address.id.should.eql(address2.id);
          address.street.should.equal('New Street');
          done();
        });
      });
    });
    
    it('should validate the update of embedded items', function(done) {
      Person.findOne(function(err, p) {
        p.addressList.updateById(address2.id, { street: null }, function(err, address) {
          err.name.should.equal('ValidationError');
          err.details.codes.street.should.eql(['presence']);
          done();
        });
      });
    });
    
    it('should find embedded items by id - verify', function(done) {
      Person.findOne(function(err, p) {
        p.addressList.findById(address2.id, function(err, address) {
          address.should.be.instanceof(Address);
          address.id.should.eql(address2.id);
          address.street.should.equal('New Street');
          done();
        });
      });
    });
    
    it('should have accessors: at, get, set', function(done) {
      Person.findOne(function(err, p) {
        p.addressList.at(0).id.should.equal(address1.id);
        p.addressList.get(address1.id).id.should.equal(address1.id);
        p.addressList.set(address1.id, { street: 'Changed 1' });
        p.addresses[0].street.should.equal('Changed 1');
        p.addressList.at(1).id.should.equal(address2.id);
        p.addressList.get(address2.id).id.should.equal(address2.id);
        p.addressList.set(address2.id, { street: 'Changed 2' });
        p.addresses[1].street.should.equal('Changed 2');
        done();
      });
    });
    
    it('should remove embedded items by id', function(done) {
      Person.findOne(function(err, p) {
        p.addresses.should.have.length(2);
        p.addressList.destroy(address1.id, function(err) {
          should.not.exist(err);
          p.addresses.should.have.length(1);
          done();
        });
      });
    });
    
    it('should have embedded items - verify', function(done) {
      Person.findOne(function(err, p) {
        p.addresses.should.have.length(1);
        done();
      });
    });
    
  });
  
  describe('embedsMany - explicit ids', function () {
    before(function (done) {
      db = getSchema();
      Person = db.define('Person', {name: String});
      Address = db.define('Address', {id: { type: String, id: true }, street: String});
      Address.validatesPresenceOf('street');

      db.automigrate(function () {
        Person.destroyAll(done);
      });
    });

    it('can be declared', function (done) {
      Person.embedsMany(Address, { options: { autoId: false, validate: true } });
      db.automigrate(done);
    });
    
    it('should create embedded items on scope', function(done) {
      Person.create({ name: 'Fred' }, function(err, p) {
        p.addressList.create({ id: 'home', street: 'Street 1' }, function(err, addresses) {
          should.not.exist(err);
          p.addressList.create({ id: 'work', street: 'Work Street 2' }, function(err, address) {
            should.not.exist(err);
            address.id.should.equal('work');
            address.street.should.equal('Work Street 2');
            done();
          });
        });
      });
    });
    
    it('should find embedded items by id', function(done) {
      Person.findOne(function(err, p) {
        p.addressList.findById('work', function(err, address) {
          address.should.be.instanceof(Address);
          address.id.should.equal('work');
          address.street.should.equal('Work Street 2');
          done();
        });
      });
    });
    
    it('should check for duplicate ids', function(done) {
      Person.findOne(function(err, p) {
        p.addressList.create({ id: 'home', street: 'Invalid' }, function(err, addresses) {
          should.exist(err);
          err.name.should.equal('ValidationError');
          err.details.codes.addresses.should.eql(['uniqueness']);
          done();
        });
      });
    });
    
    it('should update embedded items by id', function(done) {
      Person.findOne(function(err, p) {
        p.addressList.updateById('home', { street: 'New Street' }, function(err, address) {
          address.should.be.instanceof(Address);
          address.id.should.equal('home');
          address.street.should.equal('New Street');
          done();
        });
      });
    });
    
    it('should remove embedded items by id', function(done) {
      Person.findOne(function(err, p) {
        p.addresses.should.have.length(2);
        p.addressList.destroy('home', function(err) {
          should.not.exist(err);
          p.addresses.should.have.length(1);
          done();
        });
      });
    });
    
    it('should have embedded items - verify', function(done) {
      Person.findOne(function(err, p) {
        p.addresses.should.have.length(1);
        done();
      });
    });
    
    it('should validate all embedded items', function(done) {
      var addresses = [];
      addresses.push({ id: 'home', street: 'Home Street' });
      addresses.push({ id: 'work', street: '' });
      Person.create({ name: 'Wilma', addresses: addresses }, function(err, p) {
        err.name.should.equal('ValidationError');
        var expected = 'The `Person` instance is not valid. ';
        expected += 'Details: `addresses` contains invalid item: `work` (street can\'t be blank).';
        err.message.should.equal(expected);
        done();
      });
    });
    
    it('should build embedded items', function(done) {
      Person.create({ name: 'Wilma' }, function(err, p) {
        p.addressList.build({ id: 'home', street: 'Home' });
        p.addressList.build({ id: 'work', street: 'Work' });
        p.addresses.should.have.length(2);
        p.save(function(err, p) {
          done();
        });
      });
    });
    
    it('should have embedded items - verify', function(done) {
      Person.findOne({ where: { name: 'Wilma' } }, function(err, p) {
        p.name.should.equal('Wilma');
        p.addresses.should.have.length(2);
        p.addresses[0].id.should.equal('home');
        p.addresses[0].street.should.equal('Home');
        p.addresses[1].id.should.equal('work');
        p.addresses[1].street.should.equal('Work');
        done();
      });
    });
    
    it('should have accessors: at, get, set', function(done) {
      Person.findOne({ where: { name: 'Wilma' } }, function(err, p) {
        p.name.should.equal('Wilma');
        p.addresses.should.have.length(2);
        p.addressList.at(0).id.should.equal('home');
        p.addressList.get('home').id.should.equal('home');
        p.addressList.set('home', { id: 'den' }).id.should.equal('den');
        p.addressList.at(1).id.should.equal('work');
        p.addressList.get('work').id.should.equal('work');
        p.addressList.set('work', { id: 'factory' }).id.should.equal('factory');
        done();
      });
    });
    
  });
  
  describe('embedsMany - relations, scope and properties', function () {
    
    var product1, product2, product3;
    
    before(function (done) {
      db = getSchema();
      Category = db.define('Category', {name: String});
      Product = db.define('Product', {name: String});
      Link = db.define('Link', {name: String});

      db.automigrate(function () {
        Person.destroyAll(done);
      });
    });

    it('can be declared', function (done) {
      Category.embedsMany(Link, { 
        as: 'items', // rename
        scope: { include: 'product' }, // always include
        options: { belongsTo: 'product' } // optional, for add()/remove()
      });
      Link.belongsTo(Product, { 
        foreignKey: 'id', // re-use the actual product id
        properties: { id: 'id', name: 'name' }, // denormalize, transfer id
      });
      db.automigrate(function() {
        Product.create({ name: 'Product 0' }, done); // offset ids for tests
      });
    });
    
    it('should setup related items', function(done) {
      Product.create({ name: 'Product 1' }, function(err, p) {
        product1 = p;
        Product.create({ name: 'Product 2' }, function(err, p) {
          product2 = p;
          Product.create({ name: 'Product 3' }, function(err, p) {
            product3 = p;
            done();
          });
        });
      });
    });
    
    it('should create items on scope', function(done) {
      Category.create({ name: 'Category A' }, function(err, cat) {
        var link = cat.items.build();
        link.product(product1);
        var link = cat.items.build();
        link.product(product2);
        cat.save(function(err, cat) {
          var product = cat.items.at(0);
          product.should.be.instanceof(Link);
          product.should.not.have.property('productId');
          product.id.should.eql(product1.id);
          product.name.should.equal(product1.name);
          var product = cat.items.at(1);
          product.id.should.eql(product2.id);
          product.name.should.equal(product2.name);
          done();
        });
      });
    });
    
    it('should include related items on scope', function(done) {
      Category.findOne(function(err, cat) {
        cat.links.should.have.length(2);
        
        // denormalized properties:
        cat.items.at(0).should.be.instanceof(Link);
        cat.items.at(0).id.should.eql(product1.id);
        cat.items.at(0).name.should.equal(product1.name);
        cat.items.at(1).id.should.eql(product2.id);
        cat.items.at(1).name.should.equal(product2.name);
        
        // lazy-loaded relations
        should.not.exist(cat.items.at(0).product());
        should.not.exist(cat.items.at(1).product());
        
        cat.items(function(err, items) {
          cat.items.at(0).product().should.be.instanceof(Product);
          cat.items.at(1).product().should.be.instanceof(Product);
          cat.items.at(1).product().name.should.equal('Product 2');
          done();
        });
      });
    });
    
    it('should remove embedded items by id', function(done) {
      Category.findOne(function(err, cat) {
        cat.links.should.have.length(2);
        cat.items.destroy(product1.id, function(err) {
          should.not.exist(err);
          cat.links.should.have.length(1);
          done();
        });
      });
    });
    
    it('should find items on scope', function(done) {
      Category.findOne(function(err, cat) {
        cat.links.should.have.length(1);
        cat.items.at(0).id.should.eql(product2.id);
        cat.items.at(0).name.should.equal(product2.name);
        
        // lazy-loaded relations
        should.not.exist(cat.items.at(0).product());
        
        cat.items(function(err, items) {
          cat.items.at(0).product().should.be.instanceof(Product);
          cat.items.at(0).product().name.should.equal('Product 2');
          done();
        });
      });
    });
    
    it('should add related items to scope', function(done) {
      Category.findOne(function(err, cat) {
        cat.links.should.have.length(1);
        cat.items.add(product3, function(err, link) {
          link.should.be.instanceof(Link);
          link.id.should.eql(product3.id);
          link.name.should.equal('Product 3');
          
          cat.links.should.have.length(2);
          done();
        });
      });
    });
    
    it('should find items on scope', function(done) {
      Category.findOne(function(err, cat) {
        cat.links.should.have.length(2);
        
        cat.items.at(0).should.be.instanceof(Link);
        cat.items.at(0).id.should.eql(product2.id);
        cat.items.at(0).name.should.equal(product2.name);
        cat.items.at(1).id.should.eql(product3.id);
        cat.items.at(1).name.should.equal(product3.name);
        
        done();
      });
    });
    
    it('should remove embedded items by reference id', function(done) {
      Category.findOne(function(err, cat) {
        cat.links.should.have.length(2);
        cat.items.remove(product2.id, function(err) {
          should.not.exist(err);
          cat.links.should.have.length(1);
          done();
        });
      });
    });
    
    it('should remove embedded items by reference id', function(done) {
      Category.findOne(function(err, cat) {
        cat.links.should.have.length(1);
        done();
      });
    });
    
  });
  
  describe('embedsMany - polymorphic relations', function () {
    
    var person1, person2;
    
    before(function (done) {
      db = getSchema();
      Book = db.define('Book', {name: String});
      Author = db.define('Author', {name: String});
      Reader = db.define('Reader', {name: String});
      
      Link = db.define('Link'); // generic model
      Link.validatesPresenceOf('linkedId');
      Link.validatesPresenceOf('linkedType');

      db.automigrate(function () {
        Book.destroyAll(function() {
          Author.destroyAll(function() {
            Reader.destroyAll(done);
          });
        });
      });
    });

    it('can be declared', function (done) {
      Book.embedsMany(Link, { as: 'people',
        polymorphic: 'linked',
        scope: { include: 'linked' }
      });      
      Link.belongsTo('linked', {
        polymorphic: true, // needs unique auto-id
        properties: { name: 'name' } // denormalized
      });
      db.automigrate(done);
    });
    
    it('should setup related items', function(done) {
      Author.create({ name: 'Author 1' }, function(err, p) {
        person1 = p;
        Reader.create({ name: 'Reader 1' }, function(err, p) {
          person2 = p;
          done();
        });
      });
    });
    
    it('should create items on scope', function(done) {
      Book.create({ name: 'Book' }, function(err, book) {
        var link = book.people.build({ notes: 'Something ...' });
        link.linked(person1);
        var link = book.people.build();
        link.linked(person2);
        book.save(function(err, book) {
          should.not.exist(err);
          
          var link = book.people.at(0);
          link.should.be.instanceof(Link);
          link.id.should.equal(1);
          link.linkedId.should.eql(person1.id);
          link.linkedType.should.equal('Author');
          link.name.should.equal('Author 1');
          
          var link = book.people.at(1);
          link.should.be.instanceof(Link);
          link.id.should.equal(2);
          link.linkedId.should.eql(person2.id);
          link.linkedType.should.equal('Reader');
          link.name.should.equal('Reader 1');
          
          done();
        });
      });
    });
    
    it('should include related items on scope', function(done) {
      Book.findOne(function(err, book) {
        book.links.should.have.length(2);
        
        var link = book.people.at(0);
        link.should.be.instanceof(Link);
        link.id.should.equal(1);
        link.linkedId.should.eql(person1.id);
        link.linkedType.should.equal('Author');
        link.notes.should.equal('Something ...');
        
        var link = book.people.at(1);
        link.should.be.instanceof(Link);
        link.id.should.equal(2);
        link.linkedId.should.eql(person2.id);
        link.linkedType.should.equal('Reader');
        
        // lazy-loaded relations
        should.not.exist(book.people.at(0).linked());
        should.not.exist(book.people.at(1).linked());
        
        book.people(function(err, people) {
          people[0].linked().should.be.instanceof(Author);
          people[0].linked().name.should.equal('Author 1');
          people[1].linked().should.be.instanceof(Reader);
          people[1].linked().name.should.equal('Reader 1');
          done();
        });
      });
    });
    
    it('should include nested related items on scope', function(done) {
      
      // There's some date duplication going on, so it might
      // make sense to override toObject on a case-by-case basis
      // to sort this out (delete links, keep people).
      // In loopback, an afterRemote filter could do this as well.
      
      Book.find({ include: 'people' }, function(err, books) {
        var obj = books[0].toObject();
        
        obj.should.have.property('links');
        obj.should.have.property('people');
        
        obj.links.should.have.length(2);
        obj.links[0].name.should.equal('Author 1');
        obj.links[1].name.should.equal('Reader 1');
        
        obj.people.should.have.length(2);
        
        obj.people[0].name.should.equal('Author 1');
        obj.people[0].notes.should.equal('Something ...');
        
        obj.people[0].linked.name.should.equal('Author 1');
        obj.people[1].linked.name.should.equal('Reader 1');
        
        done();
      });
    });
    
  });
  
  describe('referencesMany', function () {
    
    var product1, product2, product3;
    
    before(function (done) {
      db = getSchema();
      Category = db.define('Category', {name: String});
      Product = db.define('Product', {name: String});
      
      db.automigrate(function () {
        Category.destroyAll(function() {
          Product.destroyAll(done);
        });
      });
    });

    it('can be declared', function (done) {
      var reverse = function(cb) {
        var modelInstance = this.modelInstance;
        var fk = this.definition.keyFrom;
        var ids = modelInstance[fk] || [];
        modelInstance.updateAttribute(fk, ids.reverse(), function(err, inst) {
          cb(err, inst[fk] || []);
        });
      };
      
      reverse.shared = true; // remoting
      reverse.http = { verb: 'put', path: '/products/reverse' };
      
      Category.referencesMany(Product, { scopeMethods: {
        reverse: reverse
      } });
      
      Category.prototype['__reverse__products'].should.be.a.function;
      should.exist(Category.prototype['__reverse__products'].shared);
      Category.prototype['__reverse__products'].http.should.eql(reverse.http);
      
      db.automigrate(done);
    });
    
    it('should setup test records', function (done) {
      Product.create({ name: 'Product 1' }, function(err, p) {
        product1 = p;
        Product.create({ name: 'Product 3' }, function(err, p) {
          product3 = p;
          done();
        });
      });
    });
    
    it('should create record on scope', function (done) {
      Category.create({ name: 'Category A' }, function(err, cat) {
        cat.productIds.should.be.an.array;
        cat.productIds.should.have.length(0);
        cat.products.create({ name: 'Product 2' }, function(err, p) {
          should.not.exist(err);
          cat.productIds.should.have.length(1);
          cat.productIds.should.eql([p.id]);
          p.name.should.equal('Product 2');
          product2 = p;
          done();
        });
      });
    });
    
    it('should not allow duplicate record on scope', function (done) {
      Category.findOne(function(err, cat) {
        cat.productIds = [product2.id, product2.id];
        cat.save(function(err, p) {
          should.exist(err);
          err.name.should.equal('ValidationError');
          err.details.codes.products.should.eql(['uniqueness']);
          var expected = 'The `Category` instance is not valid. ';
          expected += 'Details: `products` Contains duplicate `Product` instance.';
          err.message.should.equal(expected);
          done();
        });
      });
    });
    
    it('should find items on scope', function (done) {
      Category.findOne(function(err, cat) {
        cat.productIds.should.eql([product2.id]);
        cat.products(function(err, products) {
          should.not.exist(err);
          var p = products[0];
          p.id.should.eql(product2.id);
          p.name.should.equal('Product 2');
          done();
        });
      });
    });
    
    it('should find items on scope - findById', function (done) {
      Category.findOne(function(err, cat) {
        cat.productIds.should.eql([product2.id]);
        cat.products.findById(product2.id, function(err, p) {
          should.not.exist(err);
          p.should.be.instanceof(Product);
          p.id.should.eql(product2.id);
          p.name.should.equal('Product 2');
          done();
        });
      });
    });
    
    it('should check if a record exists on scope', function (done) {
      Category.findOne(function(err, cat) {
        cat.products.exists(product2.id, function(err, exists) {
          should.not.exist(err);
          should.exist(exists);
          done();
        });
      });
    });
    
    it('should update a record on scope', function (done) {
      Category.findOne(function(err, cat) {
        var attrs = { name: 'Product 2 - edit' };
        cat.products.updateById(product2.id, attrs, function(err, p) {
          should.not.exist(err);
          p.name.should.equal(attrs.name);
          done();
        });
      });
    });
    
    it('should get a record by index - at', function (done) {
      Category.findOne(function(err, cat) {
        cat.products.at(0, function(err, p) {
          should.not.exist(err);
          p.should.be.instanceof(Product);
          p.id.should.eql(product2.id);
          p.name.should.equal('Product 2 - edit');
          done();
        });
      });
    });
    
    it('should add a record to scope - object', function (done) {
      Category.findOne(function(err, cat) {
        cat.products.add(product1, function(err, prod) {
          should.not.exist(err);
          cat.productIds.should.eql([product2.id, product1.id]);
          prod.id.should.eql(product1.id);
          prod.should.have.property('name');
          done();
        });
      });
    });
    
    it('should add a record to scope - object', function (done) {
      Category.findOne(function(err, cat) {
        cat.products.add(product3.id, function(err, prod) {
          should.not.exist(err);
          var expected = [product2.id, product1.id, product3.id];
          cat.productIds.should.eql(expected);
          prod.id.should.eql(product3.id);
          prod.should.have.property('name');
          done();
        });
      });
    });
    
    it('should find items on scope - findById', function (done) {
      Category.findOne(function(err, cat) {
        cat.products.findById(product3.id, function(err, p) {
          should.not.exist(err);
          p.id.should.eql(product3.id);
          p.name.should.equal('Product 3');
          done();
        });
      });
    });
    
    it('should find items on scope - filter', function (done) {
      Category.findOne(function(err, cat) {
        var filter = { where: { name: 'Product 1' } };
        cat.products(filter, function(err, products) {
          should.not.exist(err);
          products.should.have.length(1);
          var p = products[0];
          p.id.should.eql(product1.id);
          p.name.should.equal('Product 1');
          done();
        });
      });
    });
    
    it('should remove items from scope', function (done) {
      Category.findOne(function(err, cat) {
        cat.products.remove(product1.id, function(err, ids) {
          should.not.exist(err);
          var expected = [product2.id, product3.id];
          cat.productIds.should.eql(expected);
          ids.should.eql(cat.productIds);
          done();
        });
      });
    });
    
    it('should find items on scope - verify', function (done) {
      Category.findOne(function(err, cat) {
        var expected = [product2.id, product3.id];
        cat.productIds.should.eql(expected);
        cat.products(function(err, products) {
          should.not.exist(err);
          products.should.have.length(2);
          products[0].id.should.eql(product2.id);
          products[1].id.should.eql(product3.id);
          done();
        });
      });
    });
    
    it('should allow custom scope methods - reverse', function(done) {
      Category.findOne(function(err, cat) {
        cat.products.reverse(function(err, ids) {
          var expected = [product3.id, product2.id];
          ids.should.eql(expected);
          cat.productIds.should.eql(expected);
          done();
        });
      })
    });
    
    it('should include related items from scope', function(done) {
      Category.find({ include: 'products' }, function(err, categories) {
        categories.should.have.length(1);
        var cat = categories[0].toObject();
        cat.name.should.equal('Category A');
        cat.products.should.have.length(2);
        cat.products[0].id.should.eql(product3.id);
        cat.products[1].id.should.eql(product2.id);
        done();
      });
    });
    
    it('should destroy items from scope - destroyById', function (done) {
      Category.findOne(function(err, cat) {
        cat.products.destroy(product2.id, function(err) {
          should.not.exist(err);
          var expected = [product3.id];
          cat.productIds.should.eql(expected);
          Product.exists(product2.id, function(err, exists) {
            should.not.exist(err);
            should.exist(exists);
            done();
          });
        });
      });
    });
    
    it('should find items on scope - verify', function (done) {
      Category.findOne(function(err, cat) {
        var expected = [product3.id];
        cat.productIds.should.eql(expected);
        cat.products(function(err, products) {
          should.not.exist(err);
          products.should.have.length(1);
          products[0].id.should.eql(product3.id);
          done();
        });
      });
    });
  
  });

});