/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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 org.apache.maven.surefire.junitcore.pc;

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.ThreadFactory;

import org.apache.maven.plugin.surefire.log.api.ConsoleLogger;
import org.junit.Test;

import static org.apache.maven.surefire.api.util.internal.DaemonThreadFactory.newDaemonThreadFactory;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertTrue;
import static org.mockito.Mockito.mock;

/**
 * Tests the factories in SchedulingStrategy.
 * <br>
 * Th point of these tests is to check {@link Task#result} if changed
 * from {@code false} to {@code true} after all scheduled tasks
 * have finished.
 * The call {@link SchedulingStrategy#finished()} is waiting until the
 * strategy has finished.
 * Then {@link Task#result} should be asserted that is {@code true}.
 *
 * @author Tibor Digana (tibor17)
 * @see SchedulingStrategy
 * @since 2.16
 */
public class SchedulingStrategiesTest {
    private static final ThreadFactory DAEMON_THREAD_FACTORY = newDaemonThreadFactory();
    private final ConsoleLogger logger = mock(ConsoleLogger.class);

    @Test
    public void invokerStrategy() throws InterruptedException {
        SchedulingStrategy strategy = SchedulingStrategies.createInvokerStrategy(logger);
        assertFalse(strategy.hasSharedThreadPool());
        assertTrue(strategy.canSchedule());

        Task task = new Task();

        strategy.schedule(task);

        assertTrue(strategy.canSchedule());

        assertTrue(task.result);

        assertTrue(strategy.finished());
        assertFalse(strategy.canSchedule());
    }

    @Test
    public void nonSharedPoolStrategy() throws InterruptedException {
        SchedulingStrategy strategy = SchedulingStrategies.createParallelStrategy(logger, 2);
        assertFalse(strategy.hasSharedThreadPool());
        assertTrue(strategy.canSchedule());

        Task task1 = new Task();
        Task task2 = new Task();

        strategy.schedule(task1);
        strategy.schedule(task2);

        assertTrue(strategy.canSchedule());

        assertTrue(strategy.finished());
        assertFalse(strategy.canSchedule());

        assertTrue(task1.result);
        assertTrue(task2.result);
    }

    @Test(expected = NullPointerException.class)
    public void sharedPoolStrategyNullPool() {
        SchedulingStrategies.createParallelSharedStrategy(logger, null);
    }

    @Test
    public void sharedPoolStrategy() throws InterruptedException {
        ExecutorService sharedPool = Executors.newCachedThreadPool(DAEMON_THREAD_FACTORY);

        SchedulingStrategy strategy1 = SchedulingStrategies.createParallelSharedStrategy(logger, sharedPool);
        assertTrue(strategy1.hasSharedThreadPool());
        assertTrue(strategy1.canSchedule());

        SchedulingStrategy strategy2 = SchedulingStrategies.createParallelSharedStrategy(logger, sharedPool);
        assertTrue(strategy2.hasSharedThreadPool());
        assertTrue(strategy2.canSchedule());

        Task task1 = new Task();
        Task task2 = new Task();
        Task task3 = new Task();
        Task task4 = new Task();

        strategy1.schedule(task1);
        strategy2.schedule(task2);
        strategy1.schedule(task3);
        strategy2.schedule(task4);

        assertTrue(strategy1.canSchedule());
        assertTrue(strategy2.canSchedule());

        assertTrue(strategy1.finished());
        assertFalse(strategy1.canSchedule());

        assertTrue(strategy2.finished());
        assertFalse(strategy2.canSchedule());

        assertTrue(task1.result);
        assertTrue(task2.result);
        assertTrue(task3.result);
        assertTrue(task4.result);
    }

    @Test
    public void infinitePoolStrategy() throws InterruptedException {
        SchedulingStrategy strategy = SchedulingStrategies.createParallelStrategyUnbounded(logger);
        assertFalse(strategy.hasSharedThreadPool());
        assertTrue(strategy.canSchedule());

        Task task1 = new Task();
        Task task2 = new Task();

        strategy.schedule(task1);
        strategy.schedule(task2);

        assertTrue(strategy.canSchedule());

        assertTrue(strategy.finished());
        assertFalse(strategy.canSchedule());

        assertTrue(task1.result);
        assertTrue(task2.result);
    }

    static class Task implements Runnable {
        volatile boolean result = false;

        @Override
        public void run() {
            result = true;
        }
    }
}
