wheels.add(new Wheel());
wheels.add(new Wheel());
wheels.add(new Wheel());
wheels.add(new Wheel());
Car c = new Car();
c.setWheels(wheels);
Ebean.save(c); // NOTE 1ST SAVE
Assert.assertFalse("No ID assigned!", c.getId() == null);
Ebean.save(c); // NOTE 2ND SAVE
List<Car> allCars = Ebean.find(Car.class).findList();
Assert.assertEquals("Inserted 1 car, received more/less!", 1, allCars.size());