package org.onlab.nio;

import org.junit.Before;

import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.TimeUnit;

import static java.util.concurrent.Executors.newSingleThreadExecutor;
import static org.junit.Assert.fail;
import static org.onlab.util.Tools.namedThreads;

/**
 * Base class for various NIO loop unit tests.
 */
public abstract class AbstractLoopTest {

    protected static final long MAX_MS_WAIT = 500;

    /** Block on specified countdown latch. Return when countdown reaches
     * zero, or fail the test if the {@value #MAX_MS_WAIT} ms timeout expires.
     *
     * @param latch the latch
     * @param label an identifying label
     */
    protected void waitForLatch(CountDownLatch latch, String label) {
        try {
            boolean ok = latch.await(MAX_MS_WAIT, TimeUnit.MILLISECONDS);
            if (!ok) {
                fail("Latch await timeout! [" + label + "]");
            }
        } catch (InterruptedException e) {
            System.out.println("Latch interrupt [" + label + "] : " + e);
            fail("Unexpected interrupt");
        }
    }

    protected ExecutorService exec;

    @Before
    public void setUp() {
        exec = newSingleThreadExecutor(namedThreads("test"));
    }

}