如何在单元测试期间注入PersistenceContext？ [英] How to inject PersistenceContext during unit testing?

问题描述

这是我的java类：

  public class Finder {
 @PersistenceContext（unitName =abc） 
 EntityManager em; 
 public boolean exists（int i）{
 return（this.em.find（Employee.class，i）！= null）; 
 
 
 $ / code $ / pre 
 
 
这是单元测试：
  public class FinderTest {
 @Test public void testSimple（）{
 Finder f = new Finder（）; 
 assert（f.exists（1）== true）; 
 
 
 
 
 
 
 
测试失败，出现 NullPointerException 因为 Finder.em 不被任何人注入。我应该如何正确处理这种情况？是否存在最佳实践？
解决方案
没有像Spring这样的容器（或者类似于 Unitils   - 这是基于Spring的），你将不得不手动注入实体管理器。在这种情况下，你可以使用类似这样的基类： 
 
 
  public abstract class JpaBaseRolledBackTestCase { 
保护静态EntityManagerFactory emf; 
 
受保护的EntityManager em; 
 
 @BeforeClass 
 public static void createEntityManagerFactory（）{
 emf = Persistence.createEntityManagerFactory（PetstorePu）; 
 
 
 @AfterClass 
 public static void closeEntityManagerFactory（）{
 emf.close（）; 
} 
 
 @Before 
 public void beginTransaction（）{
 em = emf.createEntityManager（）; 
 em.getTransaction（）。begin（）; 
 
 
 $ b $ public void rollbackTransaction（）{
 if（em.getTransaction（）。isActive（））{
 em.getTransaction（） ）.rollback（）; 
} 
 
 if（em.isOpen（））{
 em.close（）; 
} 
} 
} 
  
 
This is my java class:
public class Finder {
  @PersistenceContext(unitName = "abc")
  EntityManager em;
  public boolean exists(int i) {
    return (this.em.find(Employee.class, i) != null);
  }
}
This is the unit test:
public class FinderTest {
  @Test public void testSimple() {
    Finder f = new Finder();
    assert(f.exists(1) == true);
  }
}
Testing fails with NullPointerException since Finder.em is not injected by anyone. How should I handle this situation properly? Does there any best practice exist?
解决方案
Without a container like Spring (or something like Unitils - which is Spring based), you will have to inject the entity manager manually. In that case, you could use something like this as base class:
public abstract class JpaBaseRolledBackTestCase {
    protected static EntityManagerFactory emf;

    protected EntityManager em;

    @BeforeClass
    public static void createEntityManagerFactory() {
        emf = Persistence.createEntityManagerFactory("PetstorePu");
    }

    @AfterClass
    public static void closeEntityManagerFactory() {
        emf.close();
    }

    @Before
    public void beginTransaction() {
        em = emf.createEntityManager();
        em.getTransaction().begin();
    }

    @After
    public void rollbackTransaction() {   
        if (em.getTransaction().isActive()) {
            em.getTransaction().rollback();
        }

        if (em.isOpen()) {
            em.close();
        }
    }
}


                        
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