JMockit常见用法 -Mock Spring Bean

如今，我们的很多应用程序是基于Spring的，通过Spring IOC容器来管理我们的Java对象。所以这里单独提出对Spring Bean如何Mock方法。

以上述提到如何Mock类中的提到的AnOrdinaryClass为例，先把这个类配置在Spring的配置文件中

<?xml version="1.0" encoding="utf-8"?>
<!--suppress ALL -->
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context"
    xmlns:aop="http://www.springframework.org/schema/aop" xmlns:tx="http://www.springframework.org/schema/tx"
    xmlns:p="http://www.springframework.org/schema/p"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
        http://www.springframework.org/schema/context
        http://www.springframework.org/schema/context/spring-context-2.5.xsd
        http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-2.0.xsd
        http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-2.0.xsd"
    default-autowire="byName">

   <!-- 1个普通的spring bean-->
    <bean id="anOrdinaryBean" class="cn.jmockit.demos.AnOrdinaryClass" /> 

</beans>

同样地，讲述2种Mock方法

用Expectations来Mock。

//用Expectations来Mock Spring Bean
@ContextConfiguration(locations = { "/META-INF/applicationContext1.xml" })
@RunWith(SpringJUnit4ClassRunner.class)
public class SpringBeanMockingByExpectationsTest {
    // 注入Spring Bean，Mock这个实例，就达到了Mock Spring Bean的目的
    @Resource
    AnOrdinaryClass anOrdinaryBean;

    @Test
    public void testSpringBeanMockingByExpectation() {
        // 直接把实例传给Expectations的构造函数即可Mock这个实例
        new Expectations(anOrdinaryBean) {
            {
                // 尽管这里也可以Mock静态方法，但不推荐在这里写。静态方法的Mock应该是针对类的
                // mock普通方法
                anOrdinaryBean.ordinaryMethod();
                result = 20;
                // mock final方法
                anOrdinaryBean.finalMethod();
                result = 30;
                // native, private方法无法用Expectations来Mock
            }
        };
        Assert.assertTrue(AnOrdinaryClass.staticMethod() == 1);
        Assert.assertTrue(anOrdinaryBean.ordinaryMethod() == 20);
        Assert.assertTrue(anOrdinaryBean.finalMethod() == 30);
        // 用Expectations无法mock native方法
        Assert.assertTrue(anOrdinaryBean.navtiveMethod() == 4);
        // 用Expectations无法mock private方法
        Assert.assertTrue(anOrdinaryBean.callPrivateMethod() == 5);
    }

    @BeforeClass    
    // 加载AnOrdinaryClass类的native方法的native实现    
    public static void loadNative() throws Throwable {    
        JNITools.loadNative();    
    }    
}

用MockUp来Mock

//用MockUp来Mock Spring Bean
@ContextConfiguration(locations = { "/META-INF/applicationContext1.xml" })
@RunWith(SpringJUnit4ClassRunner.class)
public class SpringBeanMockingByMockUpTest {
    // 注入Spring Bean，Mock这个实例，就达到了Mock Spring Bean的目的
    @Resource
    AnOrdinaryClass anOrdinaryBean;

    @Test
    public void testSpringBeanMockingByMockUp() {
        // 静态方法被mock了
        Assert.assertTrue(AnOrdinaryClass.staticMethod() == 10);
        // 普通方法被mock了
        Assert.assertTrue(anOrdinaryBean.ordinaryMethod() == 20);
        // final方法被mock了
        Assert.assertTrue(anOrdinaryBean.finalMethod() == 30);
        // native方法被mock了
        Assert.assertTrue(anOrdinaryBean.navtiveMethod() == 40);
        // private方法被mock了
        Assert.assertTrue(anOrdinaryBean.callPrivateMethod() == 50);
    }

    @BeforeClass
    public static void beforeClassMethods() throws Throwable {
        loadNative();
        // 必须在Spring容器初始化前，就对Spring Bean的类做MockUp
        addMockUps();
    }


    // 加载AnOrdinaryClass类的native方法的native实现    
    public static void loadNative() throws Throwable {    
        JNITools.loadNative();    
    }    

    // 对AnOrdinaryClass的Class
    public static class AnOrdinaryClassMockUp extends MockUp<AnOrdinaryClass> {
        // Mock静态方法
        @Mock
        public static int staticMethod() {
            return 10;
        }

        // Mock普通方法
        @Mock
        public int ordinaryMethod() {
            return 20;
        }

        @Mock
        // Mock final方法
        public final int finalMethod() {
            return 30;
        }

        // Mock native方法
        @Mock
        public int navtiveMethod() {
            return 40;
        }

        // Mock private方法
        @Mock
        private int privateMethod() {
            return 50;
        }
    }

    // 添加MockUp
    public static void addMockUps() {
        new AnOrdinaryClassMockUp();
    }
}