Build E-Commerce Apps with Reactive Programming in Spring Boot/

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Crafting a Test Case

Crafting a Test Case

Learn how to write a test class for RabbitMQ.

We'll cover the following...

With everything in place, it’s time to determine what our system will do. We’re talking about an asynchronous message solution. A simple thing to implement would be receiving a request for a new Item object at a web controller and forwarding the information as a message through RabbitMQ. A service would be elsewhere, listening for messages. That service could then write the new Item to MongoDB.

This is a very simple concept we can use over and over. We can also adapt it to our needs. It’s easy to swap out the web controller with something else. Perhaps a message was also transmitted via RabbitMQ. Or, perhaps someone directly invoking the API.

Defining a test class

Let’s return to the initial problem. Namely, a web controller that turns synchronous web requests into asynchronous messages. This time, we’ll choose a test-first approach.

Spring Boot Test, JUnit 5, and Testcontainers put this at our fingertips:

@SpringBootTest //1
@AutoConfigureWebTestClient //2
@Testcontainers //3
@ContextConfiguration //4
public class RabbitTest {
    @Container static RabbitMQContainer container = new RabbitMQContainer(); //5
    @Autowired WebTestClient webTestClient; //6
    @Autowired ItemRepository repository; //7
    @DynamicPropertySource //8
    static void configure(DynamicPropertyRegistry registry) {
        registry.add("spring.rabbitmq.host", container::getContainerIpAddress);
        registry.add("spring.rabbitmq.port", container::getAmqpPort);
    }
    ...
}
Beginning with a test

Here’s a breakdown of the code above:

  1. In line 1, ...