// Starting condition is Customer has {book1: 1, book2: 2}
// Ending condition is Customer has {book1: 0, book2: 2, book3: 3}
UpdateCartDto updateCartRequest = new UpdateCartDto();
// Add a few new items
updateCartRequest.getCartItems().add(new PublicCartItemDto("0316184136",3));
// Remove by setting to zero
updateCartRequest.getCartItems().add(new PublicCartItemDto("0099410672",0));
String actualResponse = configureAsClient(PublicCartResource.class)
.accept(HalMediaType.APPLICATION_HAL_JSON)
.entity(updateCartRequest, MediaType.APPLICATION_JSON_TYPE)
.put(String.class);