NonBlockingSemaphoreTest.java

/*
 * Copyright (c) 2017 AsyncHttpClient Project. All rights reserved.
 *
 * This program is licensed to you under the Apache License Version 2.0,
 * and you may not use this file except in compliance with the Apache License Version 2.0.
 * You may obtain a copy of the Apache License Version 2.0 at
 *     http://www.apache.org/licenses/LICENSE-2.0.
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the Apache License Version 2.0 is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the Apache License Version 2.0 for the specific language governing permissions and limitations there under.
 */
package org.asynchttpclient.netty.channel;

import java.util.concurrent.Semaphore;

import org.testng.annotations.Test;

import static org.testng.Assert.*;

/**
 * @author Stepan Koltsov
 */
public class NonBlockingSemaphoreTest {

    private static class Mirror {
        private final Semaphore real;
        private final NonBlockingSemaphore nonBlocking;

        public Mirror(int permits) {
            real = new Semaphore(permits);
            nonBlocking = new NonBlockingSemaphore(permits);
        }

        public boolean tryAcquire() {
            boolean a = real.tryAcquire();
            boolean b = nonBlocking.tryAcquire();
            assertEquals(a, b);
            return a;
        }

        public void release() {
            real.release();
            nonBlocking.release();
        }
    }

    @Test
    public void test0() {
        Mirror mirror = new Mirror(0);
        assertFalse(mirror.tryAcquire());
    }

    @Test
    public void three() {
        Mirror mirror = new Mirror(3);
        for (int i = 0; i < 3; ++i) {
            assertTrue(mirror.tryAcquire());
        }
        assertFalse(mirror.tryAcquire());
        mirror.release();
        assertTrue(mirror.tryAcquire());
    }

    @Test
    public void negative() {
        Mirror mirror = new Mirror(-1);
        assertFalse(mirror.tryAcquire());
        mirror.release();
        assertFalse(mirror.tryAcquire());
        mirror.release();
        assertTrue(mirror.tryAcquire());
    }

}