无法对 @KafkaListener 注释方法进行单元测试 [英] Unable to unit test a @KafkaListener annotated method

问题描述

我正在尝试在 Spring 中对 kafka 消费者类进行单元测试.我想知道如果 kafka 消息被发送到它的主题，监听器方法被正确调用.我的消费者类是这样注释的:

I'm trying to unit test a kafka consumer class, in Spring. I want to know that if a kafka message is sent to it's topic, the listener method was called correctly. My consumer class is annotated like this:

@KafkaListener(topics = "${kafka.topics.myTopic}")
public void myKafkaMessageEvent(final String message) { ...

如果我@Autowire 一个消费者，当我发送 kafka 消息时，监听器方法被正确调用，但我不能断言该方法被调用，因为该类不是模拟.

If I @Autowire a consumer, when I send a kafka message, the listener method is called correctly, but I can't assert that the method was called because the class isn't a mock.

如果我模拟消费者，当我发送 kafka 消息时，根本不会调用侦听器方法.我可以直接调用该方法，并断言它有效，但这不是我想要的，即检查当我向其主题发送 kafka 消息时是否调用了该方法.

If I mock a consumer, when I send a kafka message the listener method is not called at all. I can call the method directly, and assert that it worked, but that doesn't do what I want, which is to check if the method is called when I send a kafka message to it's topic.

现在我已经在消费者内部放置一个计数器，并在每次调用侦听器方法时增加它，然后检查它的值是否已更改.为测试创建一个变量对我来说似乎是一个糟糕的解决方案.

For now I have resorted to put a counter inside the consumer, and increment it every time the listener method is called, then check that it's value has been changed. Making a variable just for testing seems like a terrible solution to me.

有没有办法让被模拟的消费者也收到 kafka 消息?或者以其他方式断言非模拟消费者侦听器方法被调用?

Is there maybe a way to make the mocked consumer receive the kafka messages too? Or some other way to assert that the non-mocked consumer listener method was called?

推荐答案

听起来您正在请求类似于我们在 Spring AMQP 测试框架中提供的内容:https://docs.spring.io/spring-amqp/docs/2.0.3.RELEASE/reference/html/_reference.html#test-harness

Sounds like you are requesting something similar what we have in Spring AMQP Testing Framework: https://docs.spring.io/spring-amqp/docs/2.0.3.RELEASE/reference/html/_reference.html#test-harness

所以，如果你不擅长额外的变量，你可以借用 解决方案并实现您自己的线束".

So, if you are not good with extra variable you can borrow that solution and implement your own "harness".

我认为这应该是对框架的一个很好的补充，所以，请提出一个适当的issue，我们可以一起为公众带来这样的工具.

I think that should be a good addition to the Framework so, please, raise an appropriate issue and we can together bring such a tool for the public.

更新

因此，根据 Spring AMQP 基础，我在我的测试配置中这样做了:

So, according Spring AMQP foundation I did this in my test configuration:

public static class KafkaListenerTestHarness extends KafkaListenerAnnotationBeanPostProcessor {

    private final Map<String, Object> listeners = new HashMap<>();

    @Override
    protected void processListener(MethodKafkaListenerEndpoint endpoint, KafkaListener kafkaListener,
            Object bean, Object adminTarget, String beanName) {

        bean = Mockito.spy(bean);

        this.listeners.put(kafkaListener.id(), bean);

        super.processListener(endpoint, kafkaListener, bean, adminTarget, beanName);
    }

    @SuppressWarnings("unchecked")
    public <T> T getSpy(String id) {
        return (T) this.listeners.get(id);
    }

}

...

@SuppressWarnings("rawtypes")
@Bean(name = KafkaListenerConfigUtils.KAFKA_LISTENER_ANNOTATION_PROCESSOR_BEAN_NAME)
@Role(BeanDefinition.ROLE_INFRASTRUCTURE)
public static KafkaListenerTestHarness kafkaListenerAnnotationBeanPostProcessor() {
    return new KafkaListenerTestHarness();
}

然后在目标测​​试用例中我像这样使用它:

Then in the target test-case I use it like this:

@Autowired
private KafkaListenerTestHarness harness;
...
Listener listener = this.harness.getSpy("foo");

verify(listener, times(2)).listen1("foo");

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