jmockit 能做什么

JMockit是一个Java测试框架，用于在单元测试中进行模拟(mocking)和测试驱动开发(TDD)。它能够帮助Java开发人员更方便地进行单元测试，包括模拟对象和行为、设置预期、进行验证等等。使用JMockit，可以更轻松地测试代码中的各个组件，包括类、方法、接口等等。它还支持多线程测试，能够有效地提高测试效率和质量，同时也可以帮助开发人员更好地理解代码和设计。

相关问题

Jmockit @Qualifier

JMockit is a Java library that provides support for mocking and testing. The @Qualifier annotation is used in JMockit to identify a specific instance of a bean to be used in a test.

In Spring, the @Qualifier annotation is used in a similar way to identify a specific bean to be injected into a component. However, in JMockit, the @Qualifier annotation is used in conjunction with other annotations to specify which instance of a mock or spy object to use in a test.

For example, consider a scenario where we have two implementations of a service interface and we want to mock one of them for testing. We can use the @Qualifier annotation to identify the bean to be mocked and the @Mocked annotation to create a mock object of that bean.

public interface MyService {
    String getName();
}

@Service("fooService")
public class FooService implements MyService {
    @Override
    public String getName() {
        return "Foo";
    }
}

@Service("barService")
public class BarService implements MyService {
    @Override
    public String getName() {
        return "Bar";
    }
}

public class MyServiceTest {
    @Test
    public void testGetName(@Mocked @Qualifier("fooService") MyService fooService,
                             @Mocked @Qualifier("barService") MyService barService) {
        new Expectations() {{
            fooService.getName(); result = "Mocked Foo";
            barService.getName(); result = "Mocked Bar";
        }};
        
        // Use the mocked instances of fooService and barService in the test
        // ...
    }
}

In the above example, we have two implementations of the MyService interface, FooService and BarService, and we want to mock FooService for testing. We use the @Qualifier("fooService") annotation to identify the bean to be mocked and the @Mocked annotation to create a mock object of that bean. We also create a mock object of the BarService bean using the @Mocked and @Qualifier("barService") annotations. We can then use these mocked instances of the beans in our test.

jmockit mock 私有方法

JMockit可以mock私有方法，下面是一个简单的示例：

public class PrivateMethodExample {
    private String privateMethod() {
        return "Real private method";
    }
}

@RunWith(JMockit.class)
public class PrivateMethodExampleTest {
    @Test
    public void testPrivateMethod(@Mocked PrivateMethodExample example) throws Exception {
        new Expectations() {{
           Deencapsulation.invoke(example, "privateMethod");
           result = "Mocked private method";
        }};
        
        PrivateMethodExample target = new PrivateMethodExample();
        String result = Deencapsulation.invoke(target, "privateMethod");
        assertEquals("Mocked private method", result);
    }
}

在上面的测试代码中，使用了JMockit的`@Mocked`注解来mock私有方法所在的类`PrivateMethodExample`，然后使用`Deencapsulation.invoke()`来调用被mock的私有方法，从而达到mock私有方法的目的。

需要注意的是，在mock私有方法时，需要使用`Deencapsulation.invoke()`方法来调用私有方法，而不能直接通过实例对象调用私有方法。此外，还需要在测试类中添加`@RunWith(JMockit.class)`注解。