How to use StepVerifier to process a list of products using the Webflux reactive framework - spring-boot

Question

I have list of products returned from a controller as a Flux. I am able to verify the count but I don't know how to verify the individual products. The product has a lot of properties so I do want to do a direct equals which may not work. Here is a subset of the properties of the class. The repository layer works fine and returns the data. The problem is that I don't know how to use the StepVerifier to validate the data returned by the ProductService. I am using a mock ProductRepository not shown as it just mocks return a Flux of hardcoded products like this Flux.just(productData)
import java.time.LocalDateTime;
import java.util.List;
public class ProductData {
static class Order {
String orderId;
String orderedBy;
LocalDateTime orderDate;
List<OrderItem> orderItems;
}
static class OrderItem {
String itemCode;
String name;
int quantity;
int quantityOnHold;
ItemGroup group;
}
static class ItemGroup{
String category;
String warehouseID;
String warehoueLocation;
}
}
Here is the service class.
import lombok.RequiredArgsConstructor;
import reactor.core.publisher.Flux;
#RequiredArgsConstructor
public class ProductService {
final ProductRepository productRepository;
Flux<ProductData> findAll(){
return productRepository.findAll();
}
}

Answer 1

Since your example ProductData class doesn't have any fields to verify, let's assume it has one order field:
public class ProductData {
Order order;
//rest of the code
}
Then fields can be verified like this:
#Test
void whenFindAllThenReturnFluxOfProductData() {
Flux<ProductData> products = productRepository.findAll();
StepVerifier.create(products)
.assertNext(Assertions::assertNotNull)
.assertNext(product -> {
ProductData.Order order = product.order;
LocalDateTime expectedOrderDate = LocalDateTime.now();
assertNotNull(order);
assertEquals("expectedOrderId", order.orderId);
assertEquals(expectedOrderDate, order.orderDate);
//more checks
}).assertNext(product -> {
List<ProductData.OrderItem> orderItems = product.order.orderItems;
int expectedSize = 12;
assertNotNull(orderItems);
assertEquals( expectedSize, orderItems.size());
//more checks
})
.expectComplete()
.verify();
}