Set up entity load graph test according to what's required by Hibernate 6.

As recommended in [0], we now set up our integration tests verifying the application of entity load graphs using a lazy @manytoone relationship.

[0] https://hibernate.atlassian.net/browse/HHH-15391

Related to #2423.

Author: odrotbohm

spring-data-jpa/src/test/java/org/springframework/data/jpa/domain/sample/User.java

@@ -92,8 +92,7 @@
 @Table(name = "SD_User")
 public class User {
 
-	@Id
-	@GeneratedValue(strategy = GenerationType.AUTO) private Integer id;
+	@Id @GeneratedValue(strategy = GenerationType.AUTO) private Integer id;
 	private String firstname;
 	private String lastname;
 	private int age;
@@ -106,7 +105,7 @@ public class User {
 
 	@ManyToMany private Set<Role> roles;
 
-	@ManyToOne private User manager;
+	@ManyToOne(fetch = FetchType.LAZY) private User manager;
 
 	@Embedded private Address address;
 
@@ -372,7 +371,7 @@ public boolean equals(Object obj) {
 
 		User that = (User) obj;
 
-		if (null == this.getId() || null == that.getId()) {
+		if ((null == this.getId()) || (null == that.getId())) {
 			return false;
 		}
 

spring-data-jpa/src/test/java/org/springframework/data/jpa/repository/EntityGraphRepositoryMethodsIntegrationTests.java

@@ -31,7 +31,6 @@
 import org.assertj.core.api.SoftAssertions;
 import org.junit.Assume;
 import org.junit.jupiter.api.BeforeEach;
-import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
 import org.springframework.beans.factory.annotation.Autowired;
@@ -94,7 +93,6 @@ void setup() {
 	}
 
 	@Test // DATAJPA-612
-	@Disabled // HHH-15391
 	void shouldRespectConfiguredJpaEntityGraph() {
 
 		Assume.assumeTrue(currentEntityManagerIsAJpa21EntityManager(em));