/*
 * Copyright (c) 2017, 2019 Oracle and/or its affiliates. All rights reserved.
 *
 * 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 io.helidon.common.reactive;

import org.junit.jupiter.api.Test;

import static org.hamcrest.MatcherAssert.assertThat;
import static org.hamcrest.Matchers.is;

/**
 * The UnboundedSemaphoreTest.
 */
public class UnboundedSemaphoreTest {

    @Test
    public void release() throws Exception {
        UnboundedSemaphore semaphore;

        semaphore = UnboundedSemaphore.create();
        assertThat(semaphore.release(Long.MAX_VALUE), is(Long.MAX_VALUE));

        semaphore = UnboundedSemaphore.create();
        semaphore.release(Long.MAX_VALUE / 2); // permits = Long.MAX_VALUE / 2
        semaphore.release(Long.MAX_VALUE / 2); // permits = Long.MAX_VALUE - 1
        assertThat(semaphore.availablePermits(), is(Long.MAX_VALUE - 1));

        semaphore = UnboundedSemaphore.create();
        semaphore.release(Long.MAX_VALUE / 2); // permits = Long.MAX_VALUE / 2
        semaphore.release(Long.MAX_VALUE / 2); // permits = Long.MAX_VALUE - 1
        semaphore.release(1);
        assertThat(semaphore.availablePermits(), is(Long.MAX_VALUE));

        semaphore = UnboundedSemaphore.create();
        semaphore.release(5);
        semaphore.release(7);
        assertThat(semaphore.availablePermits(), is(12L));
    }

    @Test
    public void releaseWithOverflow() throws Exception {
        UnboundedSemaphore semaphore;

        semaphore = UnboundedSemaphore.create();
        semaphore.release(Long.MAX_VALUE / 2); // permits = Long.MAX_VALUE / 2
        semaphore.release(Long.MAX_VALUE / 2); // permits = Long.MAX_VALUE - 1
        semaphore.release(1);
        assertThat(semaphore.availablePermits(), is(Long.MAX_VALUE));

        semaphore = UnboundedSemaphore.create();
        semaphore.release(Long.MAX_VALUE / 2); // permits = Long.MAX_VALUE / 2
        semaphore.release(Long.MAX_VALUE / 2); // permits = Long.MAX_VALUE - 1
        semaphore.release(2);
        assertThat(semaphore.availablePermits(), is(Long.MAX_VALUE));

        semaphore = UnboundedSemaphore.create();
        semaphore.release(Long.MAX_VALUE / 2); // permits = Long.MAX_VALUE / 2
        semaphore.release(Long.MAX_VALUE / 2); // permits = Long.MAX_VALUE - 1
        semaphore.release(Long.MAX_VALUE / 2);
        assertThat(semaphore.availablePermits(), is(Long.MAX_VALUE));

        semaphore = UnboundedSemaphore.create();
        semaphore.release(Long.MAX_VALUE / 2); // permits = Long.MAX_VALUE / 2
        semaphore.release(Long.MAX_VALUE / 2); // permits = Long.MAX_VALUE - 1
        semaphore.release(Long.MAX_VALUE);
        assertThat(semaphore.availablePermits(), is(Long.MAX_VALUE));

        semaphore = UnboundedSemaphore.create();
        semaphore.release(Long.MAX_VALUE);
        semaphore.release(Long.MAX_VALUE);
        assertThat(semaphore.availablePermits(), is(Long.MAX_VALUE));
    }
}
