/*
 * Copyright 2018 Adobe Systems Incorporated
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.adobe.cq.testing.junit.runners;

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;
import org.junit.runners.Suite;
import org.junit.runners.model.InitializationError;
import org.junit.runners.model.RunnerBuilder;
import org.junit.runners.model.RunnerScheduler;

/**
 * Junit suite for running test classes in parallel.
 *
 * <p>To be used as an annotation to an empty test class:
 *
 * <pre>
 * &#64;RunWith(ParallelSuite.class)
 * &#64;Suite.SuiteClasses({TestClass1.class, TestClass2.class})
 * public class TestClassSuiteIT {
 * }
 * </pre>
 */
public class ParallelSuite extends Suite {

  public ParallelSuite(Class<?> klass, RunnerBuilder builder) throws InitializationError {

    super(klass, builder);

    setScheduler(
        new RunnerScheduler() {

          private final ExecutorService service = Executors.newFixedThreadPool(4);

          public void schedule(Runnable childStatement) {
            service.submit(childStatement);
          }

          public void finished() {
            try {
              service.shutdown();
              service.awaitTermination(Long.MAX_VALUE, TimeUnit.NANOSECONDS);
            } catch (InterruptedException e) {
              e.printStackTrace(System.err);
            }
          }
        });
  }
}
