使用 lombok @Getter 和 @Setter 时，单元测试因 this.id 为空而失败，但在实体类上使用 @Data 时有效

Question

I am using lombok @Getter and @Setter annotations on my Entity class.

import lombok.Getter;
import lombok.Setter;

@Entity
@Table(name = "Achievements")
@Getter
@Setter
@JsonIdentityInfo(generator = ObjectIdGenerators.PropertyGenerator.class, property = "id")
public class Achievement extends DomainObject {

  private static final long serialVersionUID = 1L;

  @Column(name = "Name")
  private String name;

  @Column(name = "Details")
  private String details;

  @ManyToOne
  @JoinColumn(name = "AchievementTypeId", nullable = false)
  private AchievementType achievementType;
  
  @OneToMany(cascade = CascadeType.ALL)
  @JoinColumn(name = "QuestId")
  private Quest quest;
}

When I run the following unit test. it fails:

@Test
  public void saveAchievementTest() {
    Achievement achievement = new Achievement();
    achievement.setId(UUID.fromString(achievementId));
    AchievementRequestDTO achievementRequestDTO = new AchievementRequestDTO();
    achievementRequestDTO.setAchievementTypeId(UUID.fromString(achievementTypeId));
    achievement.setAchievementType(achievementType);
    when(achievementTypeRepository.getOne(achievementRequestDTO.getAchievementTypeId()))
        .thenReturn(achievementType);
    when(achievementRepository.save(achievement)).thenReturn(achievement);
    Achievement dbAchievement = achievementService.saveAchievement(achievementRequestDTO);
    assertEquals(dbAchievement.getId(), UUID.fromString(achievementId));
  }

The above run fails with a NullPointerException stating that dbAchievement is null . However, the same test case works when(in either of the two cases):

1. I use @Data annotation instead of @Getter and @Setter in the entity class.
2. I change the when statement in the test to when(achievementRepository.save(any())).thenReturn(achievement);

I suppose the issue here is the comparison of hashcodes to compare the object passed. I want to stick to using @Getter and @Setter in my entity. What should I do differently to achieve this?

Answer 1

Your test fails because the object you save, doesn't equal the object initialized.

Lombok's @Data incorporates @ToString @EqualsAndHashCode @Getter @Setter and @RequiredArgsConstructor

Every Java class has a default no-args constructor if there's none specified (as you have).

When you call your test, you're calling for a getId() on a field that's initialized as null

To solve this, you can seperately add the Lombok @AllArgsConstructor or the @RequiredArgsConstructor