Mockito - 监视真实对象调用原始方法

问题描述

想象一下以下代码：

List list = .....
List spy = spy(list);
doThrow(new NullpointerException()).when(spy).get(0);

doThrow（....）执行 list.get（0） - 这完全没有意义。我想定义模拟行为，而不是在这里调用方法.....我错过了什么？

doThrow(....) executes list.get(0) - this makes no sense at all. I would like to define mock behaviour and not to call a method here..... am I missing something?

编辑：
列表由CGLIB装饰。当我删除CGLIB代理时，Mockito按预期工作。任何想法在使用CGLIB代理时如何解决这样的问题？

List is decorated by CGLIB. When I remove CGLIB proxy Mockito works as expected. Any Idea how to solve such problem when using CGLIB proxies?

谢谢，
Maciej

Thanks,Maciej

推荐答案

import static org.mockito.Mockito.doThrow;
import static org.mockito.Mockito.spy;

import java.lang.reflect.Method;

import org.junit.Test;

import net.sf.cglib.proxy.Enhancer;
import net.sf.cglib.proxy.MethodInterceptor;
import net.sf.cglib.proxy.MethodProxy;

public class MockitoSpyTest {

    @Test
    public void execTest() {

        System.out.println("*** TEST 1 ***");
        System.out.println("Test on unmodified object");
        MySet ms = new MySetImpl();
        ms.set("test value");
        System.out.println("Set contains: " + ms.get());

        // decorate ms1 with easymock
        System.out.println("\n*** TEST 2 ***");
        MySet spyMs = spy(ms);
        doThrow(new NullPointerException("my test nullpointer")).when(spyMs).get();
        System.out.println("Test decorated object with SPY");
        spyMs.set("test value");
        try {
            System.out.println("Set contains: " + spyMs.get());
        } catch (NullPointerException e) {
            System.out.println("NullPointerException - as expected");
        }

        // Enhance call with CGLIB
        System.out.println("\n*** TEST 3 ***");
        System.out.println("Test on CGLIB decorated object");
        Enhancer enc = new Enhancer();
        enc.setSuperclass(MySetImpl.class);
        enc.setInterfaces(new Class[] { MySet.class });
        enc.setCallback(new MethodInterceptor() {

            @Override
            public Object intercept(Object obj, Method method, Object[] args, MethodProxy proxy) throws Throwable {
                if ("get".equals(method.getName())) {
                    System.out.println("CGLIB decorated GET call");
                }
                return proxy.invokeSuper(obj, args);
            }
        });
        MySet ms1 = (MySet) enc.create();
        ms1.set("test value");
        System.out.println("Set contains: " + ms1.get());

        // decorate ms1 with easymock
        System.out.println("\n*** TEST 4 ***");
        System.out.println("Test on CGLIB decorated object with SPY");
        MySet spyMs1 = spy(ms1);
        doThrow(new NullPointerException("my test nullpointer")).when(spyMs1).get();
        spyMs1.set("test value");
        System.out.println("Set contains: " + spyMs1.get());
    }

    public interface MySet {
        void set(String val);

        String get();
    }

    public static class MySetImpl implements MySet {
        String val;

        public void set(String val) {
            this.val = val;
            System.out.println("Original SET call:" + val);
        }

        public String get() {

            System.out.println("Original GET call:" + val);
            return val;
        }

    }
}

上面的示例产生输出：

*** TEST 1 ***
Test on unmodified object
Original SET call:test value
Original GET call:test value
Set contains: test value

*** TEST 2 ***
Test decorated object with SPY
Original SET call:test value
NullPointerException - as expected

*** TEST 3 ***
Test on CGLIB decorated object
Original SET call:test value
CGLIB decorated GET call
Original GET call:test value
Set contains: test value

*** TEST 4 ***
Test on CGLIB decorated object with SPY
CGLIB decorated GET call
Original GET call:test value
Original SET call:test value
CGLIB decorated GET call
Original GET call:test value
Set contains: test value

现在 TEST 2 和 TEST 4 应抛出 NullPointerException on GET 通话 - 基于间谍的Mockito： doThrow（新NullPointerException异常（ 我的测试空指针））时（spyMs1）获得（）;

Now the TEST 2 and TEST 4 should throw NullPointerException on get call - based on mockito spy: doThrow(new NullPointerException("my test nullpointer")).when(spyMs1).get();

TEST 4没有抛出预期的异常，因为它已经用CGLIB装饰了 - 我们也可以在控制台上看到CGLIb调用是正在执行： GLIB修饰GET调用而不调用间谍对象。使用带有CGLIB代理的Spring AOP时，可以获得相同的效果。

The "TEST 4" does not throw expected exception because it is already decorated with CGLIB - we can also see on the console that CGLIb call is being executed: GLIB decorated GET call and not call on spy object. The same effect can be achived when using Spring AOP with CGLIB proxies.

这篇关于Mockito - 监视真实对象调用原始方法的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！