如何在Spring Boot集成测试中捕获ApplicatonEvent？

Question

问题是在Spring boot测试中没有捕获到应用程序事件，而在应用程序项目中侦听事件的文件可以很好地工作。

package com.example.demo;

import org.springframework.context.ApplicationEvent;

public class CacheRefreshEvent extends ApplicationEvent {
    private String message;

    private static final long serialVersionUID = 1L;

    public CacheRefreshEvent(Object source, String message) {
        super(source);
        this.message = message;
    }

    public String getMessage() {
        return message;
    }
}

package com.example.demo;

import org.springframework.context.ApplicationEvent;

public class CacheRefreshCompleteEvent extends ApplicationEvent {
    private String message;

    private static final long serialVersionUID = 1L;

    public CacheRefreshCompleteEvent(Object source, String message) {
        super(source);
        this.message = message;
    }

    public String getMessage() {
        return message;
    }
}

package com.example.demo;
import org.springframework.context.ApplicationEventPublisher;
import org.springframework.context.ApplicationEventPublisherAware;
import org.springframework.context.ApplicationListener;
import org.springframework.stereotype.Component;

@Component
public class CaptureCacheRefreshCompleteEvent implements ApplicationListener<CacheRefreshCompleteEvent> {

    private ApplicationEventPublisher applicationEventPublisher;

    void applicationEvent() throws InterruptedException {
        applicationEventPublisher.publishEvent(new CacheRefreshEvent(this, "event triggered from SolrUtilitiesTest()"));
        Thread.sleep(5000);
        System.out.println("Finished execution of test.");
    }

    public void onApplicationEvent(CacheRefreshCompleteEvent cs) {
        System.out.println("gotcha in CaptureCachedRefreshCompleteEvent");
    }

    public void setApplicationEventPublisher(ApplicationEventPublisher arg0) {
        this.applicationEventPublisher = arg0;
    }

}

package com.example.demo;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class DemoApplication {

    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
    }

}

package com.example.demo;

import org.junit.jupiter.api.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.context.ApplicationEventPublisher;
import org.springframework.context.ApplicationEventPublisherAware;
import org.springframework.context.ApplicationListener;
import org.springframework.test.annotation.DirtiesContext;
import org.springframework.test.context.junit4.SpringRunner;

@RunWith(SpringRunner.class)
@DirtiesContext
@SpringBootTest
class DemoApplicationTests implements ApplicationEventPublisherAware, ApplicationListener<CacheRefreshCompleteEvent> {

    @Autowired
    private ApplicationEventPublisher applicationEventPublisher;

    @Test
    void applicationEvent() throws InterruptedException {
        applicationEventPublisher.publishEvent(new CacheRefreshEvent(this, "event triggered from Springboot test"));
        for(int i=0; i< 20; i ++) {
            Thread.sleep(1000);
        }
        System.out.println("Finished execution of test.");
    }

    public void onApplicationEvent(CacheRefreshCompleteEvent cs) {
        System.out.println("gotcha");
    }

    @Override
    public void setApplicationEventPublisher(ApplicationEventPublisher arg0) {
        this.applicationEventPublisher = arg0;
    }

}

Answer 1

一种方法是在测试中使用@testcomponent创建一个非常简单的侦听器，并将其autowire为@mockbean。

概念证明（用Spring Boot2.2和2.1测试）：

@SpringBootTest
public class PublishTest {
    @Autowired
    private ApplicationEventPublisher applicationEventPublisher;

    @MockBean
    private Consumer consumer;

    @Test
    public void test() {
        applicationEventPublisher.publishEvent(new TestEvent(this));

        // events are synchronous by default

        verify(consumer).consumeEvent(any(TestEvent.class));
    }

    @TestComponent
    private static class Consumer {
        @EventListener
        public void consumeEvent(TestEvent testEvent) {
        }
    }

    private static class TestEvent extends ApplicationEvent {
        public TestEvent(Object source) {
            super(source);
        }
    }
}