when: "The shopping cart is retrieved"
        HttpResponse<Cart> response = httpClient.exchange(HttpRequest.GET('/shopping/cart'), Cart) (1)
                                                .blockingFirst()
        Cart cart = response.body()
        then: "The shopping cart is present as well as a session id header"
        response.header(HttpHeaders.AUTHORIZATION_INFO) != null (2)
        cart.items.isEmpty()

        String sessionId = response.header(HttpHeaders.AUTHORIZATION_INFO); (1)
        response = client.exchange(
                HttpRequest.POST("/shopping/cart/Apple", "")
                        .header(HttpHeaders.AUTHORIZATION_INFO, sessionId), Cart.class) (2)

            val sessionId = response.header(HttpHeaders.AUTHORIZATION_INFO) (1)
            response = client.exchange(
                    HttpRequest.POST("/shopping/cart/Apple", "")
                            .header(HttpHeaders.AUTHORIZATION_INFO, sessionId), Cart::class.java) (2)
                    .blockingFirst()
            cart = response.body()