hibernate-demo/src/test/java/com/ankurm/hibernatedemo/proxy/OsivDefaultWarningTest.java

package com.ankurm.hibernatedemo.proxy;

import static org.assertj.core.api.Assertions.assertThat;

import jakarta.persistence.EntityManager;
import jakarta.persistence.EntityManagerFactory;
import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;
import org.junit.jupiter.api.Test;
import org.junit.jupiter.api.extension.ExtendWith;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.boot.test.system.CapturedOutput;
import org.springframework.boot.test.system.OutputCaptureExtension;
import org.springframework.boot.test.web.server.LocalServerPort;

/**
 * Backs docs/11-proxies-and-lazy-initialization.md, chapter "OSIV: the default, its warning, and what it actually
 * masks". Deliberately does NOT set {@code spring.jpa.open-in-view} -- Boot's own default
 * (true) is what is under test here, including the startup warning Boot prints because you
 * didn't set it explicitly.
 *
 * <p>Needs a real servlet request (see {@link OsivBookController}, {@link OsivBookService}):
 * open-in-view is implemented by {@code OpenEntityManagerInViewInterceptor}, which only exists
 * for actual web applications -- the base app here runs with
 * {@code spring.main.web-application-type=none}, so this test overrides that to {@code servlet}
 * and spins up a random-port embedded Tomcat just for itself.
 */
@ExtendWith(OutputCaptureExtension.class)
@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT, properties = {
        // A dedicated config file that has NO spring.jpa.open-in-view key at all -- the shared
        // src/main/resources/application.yml sets it to false explicitly, which would hide
        // both the warning and the masking behaviour under test here.
        "spring.config.name=osiv-default-test"
})
class OsivDefaultWarningTest {

    private static final Logger DEMO = LoggerFactory.getLogger("DEMO");

    @Autowired
    private EntityManagerFactory emf;

    @LocalServerPort
    private int port;

    private Long seedBookWithReview() {
        EntityManager em = emf.createEntityManager();
        em.getTransaction().begin();
        ProxyPublisher publisher = new ProxyPublisher("OSIV Default Press");
        em.persist(publisher);
        ProxyBook book = new ProxyBook("OSIV Default Book", publisher);
        em.persist(book);
        ProxyReview review = new ProxyReview("Rendered fine", book);
        em.persist(review);
        em.getTransaction().commit();
        Long id = book.getId();
        em.close();
        return id;
    }

    @Test
    void defaultOpenInView_printsStartupWarning_andMasksLazyLoadingDuringSerialization(CapturedOutput output) throws Exception {
        DEMO.info("checked at context-startup time: {}", output.toString().contains("open-in-view")
                ? "the OSIV warning line is present in the captured log"
                : "NOT FOUND");

        assertThat(output.toString())
                .as("Boot must print its open-in-view default warning verbatim when the property is left unset")
                .contains("spring.jpa.open-in-view is enabled by default");

        Long id = seedBookWithReview();
        HttpClient client = HttpClient.newHttpClient();
        HttpResponse<String> response = client.send(
                HttpRequest.newBuilder(URI.create("http://localhost:" + port + "/osiv/books/" + id)).GET().build(),
                HttpResponse.BodyHandlers.ofString());

        DEMO.info("default OSIV (true): GET /osiv/books/{} -> status {}, body {}", id, response.statusCode(), response.body());

        // With OSIV on, the session/EntityManager is still bound to the request thread while
        // Jackson serializes the response, so getReviews() initializes successfully instead of
        // throwing -- the exception is masked, not fixed.
        assertThat(response.statusCode()).isEqualTo(200);
        assertThat(response.body()).contains("Rendered fine");
    }
}