我是 Spring 新手，
我想测试一下 findById() 方法，但即使该条目已保存（并存在）在数据库中，也找不到该条目：

@DataJpaTest
class CustomerRepoIntegration {

    @Autowired
    CustomerRepo customerRepo;

    @Test
    @Transactional
    void findById() {
        UUID uuid = UUID.randomUUID();
        Customer customer = new Customer(uuid);
        customerRepo.save(customer);

        List<Customer> allCustomers = customerRepo.findAll();
        assertEquals(1, allCustomers.size());

        Optional<Customer> foundCustomer = customerRepo.findById(uuid);
        assertTrue(foundCustomer.isPresent());
    }
}

当第一个Assert成功时，第二个Assert失败：

Error:  Failures: 
Error:    CustomerRepoIntegration.findById:32 expected: <true> but was: <false>

其余代码：

// CustomerRepo.java
public interface CustomerRepo extends JpaRepository<Customer, UUID> {}

// Customer.java
@Entity
@Data
@NoArgsConstructor
@AllArgsConstructor
@Builder
public class Customer implements Serializable {
    @Id
    @GeneratedValue(generator = "UUID")
    @GenericGenerator(
            name = "UUID",
            strategy = "org.hibernate.id.UUIDGenerator"
    )
    private UUID id;
}

我还在这里做了一个复制回购：https://github.com/ofhouse/stackoverflow-65818312