/**
	 * @see DATAJPA-403
	 */
	@Test
	public void reusesExistingJoinForExpression() {

		CriteriaBuilder builder = em.getCriteriaBuilder();
		CriteriaQuery<User> query = builder.createQuery(User.class);
		Root<User> from = query.from(User.class);

		PropertyPath managerFirstname = PropertyPath.from("manager.firstname", User.class);
		PropertyPath managerLastname = PropertyPath.from("manager.lastname", User.class);

		QueryUtils.toExpressionRecursively(from, managerLastname);
		QueryUtils.toExpressionRecursively(from, managerFirstname);

		assertThat(from.getJoins(), hasSize(1));
	}
	/**
	 * @see DATAJPA-401
	 */
	@Test
	public void doesNotCreateAJoinForNonOptionalAssociation() {

		CriteriaBuilder builder = em.getCriteriaBuilder();
		CriteriaQuery<Order> query = builder.createQuery(Order.class);
		Root<Order> root = query.from(Order.class);

		QueryUtils.toExpressionRecursively(root, PropertyPath.from("customer", Order.class));
	}
	/**
	 * @see DATAJPA-454
	 */
	@Test
	public void createsJoingToTraverseCollectionPath() {

		CriteriaBuilder builder = em.getCriteriaBuilder();
		CriteriaQuery<User> query = builder.createQuery(User.class);
		Root<User> root = query.from(User.class);

		QueryUtils.toExpressionRecursively(root, PropertyPath.from("colleaguesLastname", User.class));

		assertThat(root.getJoins(), hasSize(1));
	}
	/**
	 * @see DATAJPA-401
	 */
	@Test
	public void createsJoinForOptionalAssociation() {

		CriteriaBuilder builder = em.getCriteriaBuilder();
		CriteriaQuery<User> query = builder.createQuery(User.class);
		Root<User> root = query.from(User.class);

		QueryUtils.toExpressionRecursively(root, PropertyPath.from("manager", User.class));

		assertThat(root.getJoins(), hasSize(1));
	}