如何在测试期间修改静态私有字段？-Java 学习之路

我的项目使用 JUnit ， Mockito ， PowerMockito 来创建单元测试 . 代码如下：

public class FirstController {
    public void doSomething() {
        ServiceExecutor.execute();
    }
}

public class ServiceExecutor {

    private static final List<Service> services = Arrays.asList(
        new Service1(),
        new Service2(),
        ...
    );

    public static void execute() {
        for (Service s : services) {
            s.execute();
        }
    }   
}

@RunWith(PowerMockRunner.class)
@PrepareForTest({ServiceExecutor.class})
public class FirstControllerTest {

        @Before
        public void prepareForTest() {
            PowerMockito.mockStatic(ServiceExecutor.class);
            PowerMockito.doNothing().when(ServiceExecutor.class)
        }

        @Test
        public void doSomethingTest() {
            FirstController firstController = new FirstController();
            firstController.doSomething();
            PowerMockito.verifyStatic(ServiceExecutor.class, Mockito.times(1));
        }   
    }

我想验证运行的 ServiceExecutor.execute() 方法 .

当调用 execute() 方法时，我试图模拟 ServiceExecutor 和 doNothing() . 但我在 ServiceExecutor 中的 private static final List<Service> services 有问题 . 它始终为每个服务构造新实例 . 每个服务都需要更长的时间来创建新实例，如果我模拟每个 Service ，我不知道他们以后会有多少服务 .

您是否有任何想法在 FirstController 中验证 ServiceExecutor.execute() 而无需在 ServiceExecutor 中运行任何方法？

1 回答

所以你知道如何模拟ServiceExecutor.execute，但你不想模仿它 . 您希望在测试中执行它，但不在测试中运行所有service.execute（）方法 . 这不是对FirstController的测试，而是对ServiceExecutor的测试 . 所以你可以减少你的问题 .

您可以使用Reflection在测试中更改私有静态字段ServiceExecutor.services的值，如下所述：Change private static final field using Java reflection

public class ServiceExecutorTest {

    @Test
    public void doSomethingTest() throws NoSuchFieldException, IllegalAccessException {
        Field field = null;
        List<Service> oldList = null;
        try {
            field = ServiceExecutor.class.getDeclaredField("services");
            field.setAccessible(true);
            Field modifiersField = Field.class.getDeclaredField("modifiers");
            modifiersField.setAccessible(true);
            modifiersField.setInt(field, field.getModifiers() & ~Modifier.FINAL);

            final Service serviceMock1 = mock(Service.class);
            final Service serviceMock2 = mock(Service.class);
            final List<Service> serviceMockList = Arrays.asList(serviceMock1, serviceMock2);
            oldList = (List<Service>) field.get(null);
            field.set(null, serviceMockList);
            ServiceExecutor.execute();
            verify(serviceMock1, times(1)).execute();
            verify(serviceMock2, times(1)).execute();
        } finally {
            // restore original value
            if (field != null && oldList != null) {
                field.set(null, oldList);
            }
        }
    }

    static class Service {
        void execute() {
            throw new RuntimeException("Should not execute");
        }
    }

    static class ServiceExecutor {

        private static final List<Service> services = Arrays.asList(
                new Service());

        public static void execute() {
            for (Service s : services) {
                s.execute();
            }
        }
    }
}

回复于 2024-05-06T04:09:12+08:00

如何在测试期间修改静态私有字段？

1 回答

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