jpa - 使用 JUnit 测试 EJB

Question

我应该如何测试注入(inject) EntityManager 实例的 EJB 3.1？

可能的 EJB:

@Stateless
@LocalBean
public class CommentService {

    @PersistenceContext
    private EntityManager em;

    public List<Comment> findAll() {
        TypedQuery<Comment> query = em.createNamedQuery(
            Comment.FIND_ALL, Comment.class
        );
        return query.getResultList();
    }

}

可能的测试:

@Test
public void testFindAll() {
    List<Comment> all = service.findAll();
    Assert.assertEquals(8, all.size());
}

我仅使用适用于 Java EE 开发人员的 GlassFish 3.1 和 Eclipse Indigo。我已经尝试过类似的事情:

@Before
public void setUp() throws Exception {
    ejbContainer = EJBContainer.createEJBContainer();
    service = (CommentService) ejbContainer.getContext()
        .lookup("java:global/classes/CommentService");
}

但我得到的只是:

javax.ejb.EJBException:
No EJBContainer provider available: no provider names had been found.

Answer 1

接受的答案需要模拟大量代码，包括持久层。使用嵌入式容器来测试实际的bean；否则，模拟持久层会导致代码几乎无法测试任何有用的东西。

将 session bean 与引用持久性单元的实体管理器一起使用:

@Stateless
public class CommentService {

    @PersistenceContext(unitName = "pu")
    private EntityManager em;

    public void create(Comment t) {
        em.merge(t);
    }

    public Collection<Comment> getAll() {
        Query q = em.createNamedQuery("Comment.findAll");
        Collection<Comment> entities = q.getResultList();
        return entities;
    }
}

实体bean:

@Entity
@NamedQueries({@NamedQuery(name = "Comment.findAll", query = "select e from Comment e")})
public class Comment implements Serializable {
    private static final long serialVersionUID = 1L;
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }
}

此持久单元在 persistence.xml 文件中定义如下:

<persistence version="2.1" xmlns="http://xmlns.jcp.org/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence http://xmlns.jcp.org/xml/ns/persistence/persistence_2_1.xsd">

  <persistence-unit name="pu" transaction-type="JTA">
    <provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>
    <class>org.glassfish.embedded.tempconverter.Comment</class>
    <properties>
      <property name="eclipselink.ddl-generation" value="drop-and-create-tables"/>
    </properties>
  </persistence-unit>
</persistence>

事务类型必须是JTA。

然后编写一个创建和销毁 EJB 容器(GlassFish 嵌入式容器)的测试:

public class CommentTest extends TestCase {

     private Context  ctx;
     private EJBContainer ejbContainer;

    @BeforeClass
    public  void setUp() {
        ejbContainer = EJBContainer.createEJBContainer();
        System.out.println("Opening the container" );
        ctx = ejbContainer.getContext();
    }

    @AfterClass
    public  void tearDown() {
        ejbContainer.close();
        System.out.println("Closing the container" );
    }

    public void testApp() throws NamingException {

        CommentService converter = (CommentService) ctx.lookup("java:global/classes/CommentService");
        assertNotNull(converter);

        Comment t = new Comment();
        converter.create(t);
        t = new Comment();
        converter.create(t);
        t = new Comment();
        converter.create(t);
        t = new Comment();
        converter.create(t);

        Collection<Comment> ts = converter.getAll();

        assertEquals(4, ts.size());
    }
}

接下来，添加两个依赖项(例如 Maven POM):

<dependency>
    <groupId>junit</groupId>
    <artifactId>junit</artifactId>
    <version>4.8.2</version>
    <scope>test</scope>
    <type>jar</type>
</dependency>
<dependency>
    <groupId>org.glassfish.main.extras</groupId>
    <artifactId>glassfish-embedded-all</artifactId>
    <version>3.1.2</version>
    <scope>compile</scope>
</dependency>

拥有依赖项、 session 和实体 bean、持久性文件、测试 文件完全按照所示实现，那么测试应该通过。 (互联网上的例子远远不够。)