Test the API

Now let's create a real test for our API which will verify the business logic.

package com.example.demo.api;

import com.example.demo.model.Rating;
import com.example.demo.support.AbstractIntegrationTest;
import org.junit.Test;

import static io.restassured.RestAssured.given;
import static org.awaitility.Awaitility.await;
import static org.hamcrest.Matchers.is;

public class RatingsControllerTest extends AbstractIntegrationTest {

    @Test
    public void testRatings() {
        String talkId = "welcome-to-junit-5";

        given(requestSpecification)
                .body(new Rating(talkId, 5))
                .when()
                .post("/ratings")
                .then()
                .statusLine("HTTP/1.1 202 Accepted");

        await().untilAsserted(() -> {
            given(requestSpecification)
                    .queryParam("talkId", talkId)
                    .when()
                    .get("/ratings")
                    .then()
                    .body("5", is(1));
        });

        for (int i = 1; i <= 5; i++) {
            given(requestSpecification)
                    .body(new Rating(talkId, i))
                    .when()
                    .post("/ratings");
        }

        await().untilAsserted(() -> {
            given(requestSpecification)
                    .queryParam("talkId", talkId)
                    .when()
                    .get("/ratings")
                    .then()
                    .body("1", is(1))
                    .body("2", is(1))
                    .body("3", is(1))
                    .body("4", is(1))
                    .body("5", is(2));
        });
    }

    @Test
    public void testUnknownTalk() {
        String talkId = "cdi-the-great-parts";

        given(requestSpecification)
                .body(new Rating(talkId, 5))
                .when()
                .post("/ratings")
                .then()
                .statusLine("HTTP/1.1 400 Bad Request");
    }
}

Run it, and it will fail. Why? There is no Kafka!

But running Kafka in Docker is challenging and not as simple as doing new GenericContainer. But don't worry, there is KafkaContainer from Testcontainers.

Just add it the same way as you added Redis and set spring.kafka.bootstrap-servers system property.

Hint 1:

Some containers expose helper methods. Check if there is one on KafkaContainer which might help you.

Hint 2:

You can start a few containers in parallel by doing:

Stream.of(redis, kafka).parallel().forEach(GenericContainer::start);