junit5 - 并行运行测试（在 pom 中没有 forkCount）答案

【问题标题】：junit5 - run tests in parallel (without forkCount in pom)junit5 - 并行运行测试（在 pom 中没有 forkCount）
【发布时间】：2018-06-07 23:23:10
【问题描述】：

为了并行执行我的 JUnit 测试，我使用了here 提供的解决方案（感谢@peanut 和@Reid Mac）。这适用于 JUnit 4，但我正在尝试从 JUnit 4 迁移到 JUnit 5。由于 JUnit 5 测试由直接扩展 Runner 的JUnitPlatform 执行，因此 JUnit 5 无法实现等价物。JUnit 5 是否有像setScheduler 这样的方法吗？下面是我的代码 sn-ps。

JUnit4Runner.class

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import java.util.LinkedList;
import java.util.Queue;
import java.util.concurrent.CompletionService;
import java.util.concurrent.ExecutorCompletionService;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import java.util.concurrent.ThreadFactory;
import java.util.concurrent.atomic.AtomicInteger;

import org.junit.runners.Suite;
import org.junit.runners.model.InitializationError;
import org.junit.runners.model.RunnerBuilder;
import org.junit.runners.model.RunnerScheduler;

public final class JUnit4Runner extends Suite {


    @Retention(RetentionPolicy.RUNTIME)
    @Target({ ElementType.TYPE })
    public @interface Concurrent {
        int threads() default 1;
    }

    /**
     * Used by JUnit Concurrent
     * https://stackoverflow.com/questions/5674774/running-junit-test-in-parallel-on-suite-level
     */
    public AJUnit4Runner2(Class<?> suiteClass, RunnerBuilder builder) throws InitializationError {
        super(suiteClass, builder);
        setScheduler(new RunnerScheduler() {
            ExecutorService executorService = Executors.newFixedThreadPool(
                    suiteClass.isAnnotationPresent(Concurrent.class)
                            ? suiteClass.getAnnotation(Concurrent.class).threads()
                            : 1,
                    new NamedThreadFactory(suiteClass.getSimpleName()));
            CompletionService<Void> completionService = new ExecutorCompletionService<Void>(executorService);
            Queue<Future<Void>> tasks = new LinkedList<Future<Void>>();

            @Override
            public void schedule(Runnable childStatement) {
                tasks.offer(completionService.submit(childStatement, null));
            }

            @Override
            public void finished() {
                try {
                    while (!tasks.isEmpty()) {
                        tasks.remove(completionService.take());
                    }
                } catch (InterruptedException e) {
                    Thread.currentThread().interrupt();
                } finally {
                    while (!tasks.isEmpty()) {
                        tasks.poll().cancel(true);
                    }
                    executorService.shutdownNow();
                }
            }
        });
    }

    class NamedThreadFactory implements ThreadFactory {

        final AtomicInteger poolNumber = new AtomicInteger(1);
        final AtomicInteger threadNumber = new AtomicInteger(1);
        final ThreadGroup group;

        public NamedThreadFactory(String poolName) {
            group = new ThreadGroup(poolName + "-" + poolNumber.getAndIncrement());
        }

        @Override
        public Thread newThread(Runnable r) {
            return new Thread(group, r, group.getName() + "-thread-" + threadNumber.getAndIncrement(), 0);
        }
    }

}

JUnit5 runner 类看起来像这样

JUnit5Runner.class

public class JUnit5Runner extends JUnitPlatform {
    public JUnit5Runner(Class<?> testClass) throws InitializationError {
        super(testClass);
        ...
    }

    @Override
    public void run(RunNotifier notifier) {
        super.run(notifier);
    }
}

【问题讨论】：

标签： java maven junit junit5

【解决方案1】：

Junit 5.3 M1 现在支持并行测试执行。正如documentation 中提到的，它目前是一个实验性功能。您可以通过在 junit-platform.properties 中将 junit.jupiter.execution.parallel.enabled 配置参数设置为 true 来启用它。

【讨论】：