java Junit Test - ExecutorService

[lepffm]

Problem

ExecutorService 를 사용하여 별도의 스레드로 실행시키는 메소드를 테스트 할 경우 다른 스레드로 실행되므로 테스트 시 정상적인 리턴값을 받아오지 못하는 문제가 발생함.

Solving

replace ExecutorService field to MoreExecutors.newDirectExecutorService()

if the filed is declared Bean then use @Mock annotation. but it just declared normal field, you must use ReflectionTestUtils of Spring Framework

// Test Target
public class YourService {
    private static ExecutorService executor = Executors.newFixedThreadPool(5);
    public void start(List<YourVO> vos) {
        vos.forEach(vo -> executor.execute(() ->
           { ..... } // do something 
          )
        );
    }

// Test Code
import com.google.common.util.concurrent.MoreExecutors;
import org.springframework.test.util.ReflectionTestUtils;
        // if static field 
        ReflectionTestUtils.setField(YourService.class,"executor", MoreExecutors.newDirectExecutorService());
        // if not static field 
         ReflectionTestUtils.setField(yourServiceInstance.class,"executor", MoreExecutors.newDirectExecutorService());

[lepffm]

comment test