模拟测试错误.需要但未调用的异常

Question

我是Mockito的新手，无法理解这是什么问题。你能告诉我，如何正确地做Mockito单位吗，因为我真的不懂它们!

我有下一个例外:

java.lang.NullPointerException在ua.khpi.shapoval.autostation.service.MySqlUsersService.getUserIdByLogin (MySqlUsersService.java: 49)在ua.khpi.shapoval.autostation.dao.UsersServiceTest.testGetUserByLogin (UsersServiceTest.java: 57)在sun.reflect.NativeMethodAccessorImpl。invoke0(本地方法)sun.reflect.NativeMethodAccessorImpl.invoke (NativeMethodAccessorImpl.java: 62)sun.reflect.DelegatingMethodAccessorImpl.invoke (DelegatingMethodAccessorImpl.java: 43)java.lang.reflect.Method.invoke (Method.java: 498)org.junit.runners.model.FrameworkMethod runreflectivecall 1.美元(FrameworkMethod.java: 50)org.junit.internal.runners.model.ReflectiveCallable.run (ReflectiveCallable.java: 12)在org.junit.runners.model.FrameworkMethod.invokeExplosively (FrameworkMethod.java: 47)在org.junit.internal.runners.statements.InvokeMethod.evaluate (InvokeMethod.java: 17)在org.junit.internal.runners.statements.RunBefores.evaluate (RunBefores.java: 26)org.junit.runners.ParentRunner.runLeaf (ParentRunner.java: 325)org.junit.runners.BlockJUnit4ClassRunner.runChild (BlockJUnit4ClassRunner.java: 78)在org.junit.runners.BlockJUnit4ClassRunner.runChild (BlockJUnit4ClassRunner.java: 57)在org.junit.runners.ParentRunner 3.美元运行(ParentRunner.java: 290)在org.junit.runners.ParentRunner 1.美元计划(ParentRunner.java: 71)org.junit.runners.ParentRunner.runChildren (ParentRunner.java: 288)org.junit.runners.ParentRunner.access 000美元(ParentRunner.java: 58)org.junit.runners.ParentRunner评估2.美元(ParentRunner.java: 268)org.junit.runners.ParentRunner.run (ParentRunner.java: 363)org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run (JUnit4TestReference.java: 86)在org.eclipse.jdt.internal.junit.runner.TestExecution.run (TestExecution.java: 38)org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests (RemoteTestRunner.java: 459)org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests (RemoteTestRunner.java: 675)org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run (RemoteTestRunner.java: 382)org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main (RemoteTestRunner.java: 192)

这是我的DAO类:

  public class MySqlUsersDao implements UsersDao {
        /** Logger. */
        private static final Logger LOG = Logger.getLogger(MySqlUsersDao.class);
        /*
         * (non-Javadoc)
         * 
         * @see
         * ua.khpi.shapoval.autostation.dao.UsersDao#getUserIdByLogin(java.lang.
         * String)
         */
        @Override
        public int getUserIdByLogin(String login) {
            Connection connection = null;
            PreparedStatement stmt = null;
            ResultSet rs = null;
            try {
                connection = DbConnector.getConnection();
                stmt = connection.prepareStatement(Constants.UsersDao.SELECT_USER_ID_BY_LOGIN);
                stmt.setString(1, login);
                rs = stmt.executeQuery();
                while (rs.next()) {
                    return rs.getInt(1);
                }
            } catch (SQLException e) {
                LOG.error(e.getMessage());
                return 0;
            } finally {
                DbConnector.close(connection, stmt, rs);
            }
            return 0;
        }

    }

这是我的Service类

   public class MySqlUsersService implements UsersService {
    private UsersDao usersDao;
    private TransactionManager transactionManager;
    public MySqlUsersService(UsersDao usersDao, TransactionManager transactionManager) {
        this.usersDao = usersDao;
        this.transactionManager = transactionManager;
    }
    @Override
    public int getUserIdByLogin(String login) {
        return this.transactionManager.execute(() -> this.usersDao.getUserIdByLogin(login));
    }
}

这是Mockito的测试类

public class UsersServiceTest {
    @InjectMocks
    private MySqlUsersService mockedUsersService;
    @Mock
    private static TransactionManager transactionManager;
    @Mock
    private static UsersDao usersDao;
    @Mock
    private static Users user1;
    @Before
    public void init() {
        MockitoAnnotations.initMocks(this);
    }
    @Test public void testGetUserByLogin() {
        when(usersDao.getUserByLogin("user1")).thenReturn(user1);
        assertEquals(user1, mockedUsersService.getUserIdByLogin("user1")); 
        verify(transactionManager).execute(()->usersDao.getUserIdByLogin("user1"));
    }
}

Answer 1

如果我理解正确的话

verify(transactionManager).execute(()->usersDao.getUserByLogin("user1"));

这是因为函数是通过引用进行比较的，在测试中传递的函数和在实现中传递的函数是不同的实例。

我建议您使用ArgumentCaptor捕获函数。调用捕获的函数并验证它是否按照您的期望执行。

Answer 2

错误消息告诉您验证语句没有在testGetUserByLogin()中执行。

我认为你的实际问题是测试类应该在你的测试类中注释@ injectmock。这个注释告诉Mockito将mock注入到哪个类中:

@InjectMocks
private MySqlUsersService mockedUsersService

我会这样重写你的测试:

public class UsersServiceTest { 
@InjectMocks
private MySqlUsersService mockedUsersService;
@Mock 
private static TransactionManager transactionManager;
@Mock
 private static UsersDao usersDao;
@Mock 
private static Users user1;
@Before 
public static void init() { initMocks(this); }
@Test public void testGetUserByLogin() {
    when(usersDao.getUserByLogin("user1")).thenReturn(user1);
    assertEquals(user1, mockedUsersService.getUserIdByLogin("user1")); 
    verify(transactionManager).execute(()->usersDao.getUserIdByLogin("user1"));
} }