/*
 * ====================================================================
 * 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.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 *
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package org.apache.hc.core5.pool;

import java.util.Collections;
import java.util.concurrent.CancellationException;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;

import org.apache.hc.core5.http.HttpConnection;
import org.apache.hc.core5.io.CloseMode;
import org.apache.hc.core5.util.DeadlineTimeoutException;
import org.apache.hc.core5.util.TimeValue;
import org.apache.hc.core5.util.Timeout;
import org.junit.Assert;
import org.junit.Test;
import org.mockito.ArgumentMatchers;
import org.mockito.Mockito;

public class TestStrictConnPool {

    @Test
    public void testEmptyPool() throws Exception {
        final StrictConnPool<String, HttpConnection> pool = new StrictConnPool<>(2, 10);
        final PoolStats totals = pool.getTotalStats();
        Assert.assertEquals(0, totals.getAvailable());
        Assert.assertEquals(0, totals.getLeased());
        Assert.assertEquals(0, totals.getPending());
        Assert.assertEquals(10, totals.getMax());
        Assert.assertEquals(Collections.emptySet(), pool.getRoutes());
        final PoolStats stats = pool.getStats("somehost");
        Assert.assertEquals(0, stats.getAvailable());
        Assert.assertEquals(0, stats.getLeased());
        Assert.assertEquals(0, stats.getPending());
        Assert.assertEquals(2, stats.getMax());
        Assert.assertEquals("[leased: 0][available: 0][pending: 0]", pool.toString());
    }

    @Test
    public void testInvalidConstruction() throws Exception {
        try {
            new StrictConnPool<String, HttpConnection>(-1, 1);
            Assert.fail("IllegalArgumentException should have been thrown");
        } catch (final IllegalArgumentException expected) {
        }
        try {
            new StrictConnPool<String, HttpConnection>(1, -1);
            Assert.fail("IllegalArgumentException should have been thrown");
        } catch (final IllegalArgumentException expected) {
        }
    }

    @Test
    public void testLeaseRelease() throws Exception {
        final HttpConnection conn1 = Mockito.mock(HttpConnection.class);
        final HttpConnection conn2 = Mockito.mock(HttpConnection.class);
        final HttpConnection conn3 = Mockito.mock(HttpConnection.class);

        final StrictConnPool<String, HttpConnection> pool = new StrictConnPool<>(2, 10);
        final Future<PoolEntry<String, HttpConnection>> future1 = pool.lease("somehost", null);
        final Future<PoolEntry<String, HttpConnection>> future2 = pool.lease("somehost", null);
        final Future<PoolEntry<String, HttpConnection>> future3 = pool.lease("otherhost", null);

        final PoolEntry<String, HttpConnection> entry1 = future1.get();
        Assert.assertNotNull(entry1);
        entry1.assignConnection(conn1);
        final PoolEntry<String, HttpConnection> entry2 = future2.get();
        Assert.assertNotNull(entry2);
        entry2.assignConnection(conn2);
        final PoolEntry<String, HttpConnection> entry3 = future3.get();
        Assert.assertNotNull(entry3);
        entry3.assignConnection(conn3);

        pool.release(entry1, true);
        pool.release(entry2, true);
        pool.release(entry3, false);
        Mockito.verify(conn1, Mockito.never()).close(ArgumentMatchers.<CloseMode>any());
        Mockito.verify(conn2, Mockito.never()).close(ArgumentMatchers.<CloseMode>any());
        Mockito.verify(conn3, Mockito.times(1)).close(CloseMode.GRACEFUL);

        final PoolStats totals = pool.getTotalStats();
        Assert.assertEquals(2, totals.getAvailable());
        Assert.assertEquals(0, totals.getLeased());
        Assert.assertEquals(0, totals.getPending());
    }

    @Test
    public void testLeaseInvalid() throws Exception {
        final StrictConnPool<String, HttpConnection> pool = new StrictConnPool<>(2, 10);
        try {
            pool.lease(null, null, Timeout.ZERO_MILLISECONDS, null);
            Assert.fail("NullPointerException should have been thrown");
        } catch (final NullPointerException expected) {
        }
        try {
            pool.lease("somehost", null, null, null);
            Assert.fail("IllegalArgumentException should have been thrown");
        } catch (final NullPointerException expected) {
        }
    }

    @Test(expected = IllegalStateException.class)
    public void testReleaseUnknownEntry() throws Exception {
        final StrictConnPool<String, HttpConnection> pool = new StrictConnPool<>(2, 2);
        pool.release(new PoolEntry<>("somehost"), true);
    }

    @Test
    public void testMaxLimits() throws Exception {
        final HttpConnection conn1 = Mockito.mock(HttpConnection.class);
        final HttpConnection conn2 = Mockito.mock(HttpConnection.class);
        final HttpConnection conn3 = Mockito.mock(HttpConnection.class);

        final StrictConnPool<String, HttpConnection> pool = new StrictConnPool<>(2, 10);
        pool.setMaxPerRoute("somehost", 2);
        pool.setMaxPerRoute("otherhost", 1);
        pool.setMaxTotal(3);

        final Future<PoolEntry<String, HttpConnection>> future1 = pool.lease("somehost", null);
        final Future<PoolEntry<String, HttpConnection>> future2 = pool.lease("somehost", null);
        final Future<PoolEntry<String, HttpConnection>> future3 = pool.lease("otherhost", null);

        final PoolEntry<String, HttpConnection> entry1 = future1.get();
        Assert.assertNotNull(entry1);
        entry1.assignConnection(conn1);
        final PoolEntry<String, HttpConnection> entry2 = future2.get();
        Assert.assertNotNull(entry2);
        entry2.assignConnection(conn2);
        final PoolEntry<String, HttpConnection> entry3 = future3.get();
        Assert.assertNotNull(entry3);
        entry3.assignConnection(conn3);

        pool.release(entry1, true);
        pool.release(entry2, true);
        pool.release(entry3, true);

        final PoolStats totals = pool.getTotalStats();
        Assert.assertEquals(3, totals.getAvailable());
        Assert.assertEquals(0, totals.getLeased());
        Assert.assertEquals(0, totals.getPending());

        final Future<PoolEntry<String, HttpConnection>> future4 = pool.lease("somehost", null);
        final Future<PoolEntry<String, HttpConnection>> future5 = pool.lease("somehost", null);
        final Future<PoolEntry<String, HttpConnection>> future6 = pool.lease("otherhost", null);
        final Future<PoolEntry<String, HttpConnection>> future7 = pool.lease("somehost", null);
        final Future<PoolEntry<String, HttpConnection>> future8 = pool.lease("somehost", null);
        final Future<PoolEntry<String, HttpConnection>> future9 = pool.lease("otherhost", null);

        Assert.assertTrue(future4.isDone());
        final PoolEntry<String, HttpConnection> entry4 = future4.get();
        Assert.assertNotNull(entry4);
        Assert.assertSame(conn2, entry4.getConnection());

        Assert.assertTrue(future5.isDone());
        final PoolEntry<String, HttpConnection> entry5 = future5.get();
        Assert.assertNotNull(entry5);
        Assert.assertSame(conn1, entry5.getConnection());

        Assert.assertTrue(future6.isDone());
        final PoolEntry<String, HttpConnection> entry6 = future6.get();
        Assert.assertNotNull(entry6);
        Assert.assertSame(conn3, entry6.getConnection());

        Assert.assertFalse(future7.isDone());
        Assert.assertFalse(future8.isDone());
        Assert.assertFalse(future9.isDone());

        pool.release(entry4, true);
        pool.release(entry5, false);
        pool.release(entry6, true);

        Assert.assertTrue(future7.isDone());
        final PoolEntry<String, HttpConnection> entry7 = future7.get();
        Assert.assertNotNull(entry7);
        Assert.assertSame(conn2, entry7.getConnection());

        Assert.assertTrue(future8.isDone());
        final PoolEntry<String, HttpConnection> entry8 = future8.get();
        Assert.assertNotNull(entry8);
        Assert.assertEquals(null, entry8.getConnection());

        Assert.assertTrue(future9.isDone());
        final PoolEntry<String, HttpConnection> entry9 = future9.get();
        Assert.assertNotNull(entry9);
        Assert.assertSame(conn3, entry9.getConnection());
    }

    @Test
    public void testConnectionRedistributionOnTotalMaxLimit() throws Exception {
        final HttpConnection conn1 = Mockito.mock(HttpConnection.class);
        final HttpConnection conn2 = Mockito.mock(HttpConnection.class);
        final HttpConnection conn3 = Mockito.mock(HttpConnection.class);
        final HttpConnection conn4 = Mockito.mock(HttpConnection.class);
        final HttpConnection conn5 = Mockito.mock(HttpConnection.class);

        final StrictConnPool<String, HttpConnection> pool = new StrictConnPool<>(2, 10);
        pool.setMaxPerRoute("somehost", 2);
        pool.setMaxPerRoute("otherhost", 2);
        pool.setMaxTotal(2);

        final Future<PoolEntry<String, HttpConnection>> future1 = pool.lease("somehost", null);
        final Future<PoolEntry<String, HttpConnection>> future2 = pool.lease("somehost", null);
        final Future<PoolEntry<String, HttpConnection>> future3 = pool.lease("otherhost", null);
        final Future<PoolEntry<String, HttpConnection>> future4 = pool.lease("otherhost", null);

        Assert.assertTrue(future1.isDone());
        final PoolEntry<String, HttpConnection> entry1 = future1.get();
        Assert.assertNotNull(entry1);
        Assert.assertFalse(entry1.hasConnection());
        entry1.assignConnection(conn1);
        Assert.assertTrue(future2.isDone());
        final PoolEntry<String, HttpConnection> entry2 = future2.get();
        Assert.assertNotNull(entry2);
        Assert.assertFalse(entry2.hasConnection());
        entry2.assignConnection(conn2);

        Assert.assertFalse(future3.isDone());
        Assert.assertFalse(future4.isDone());

        PoolStats totals = pool.getTotalStats();
        Assert.assertEquals(0, totals.getAvailable());
        Assert.assertEquals(2, totals.getLeased());
        Assert.assertEquals(2, totals.getPending());

        pool.release(entry1, true);
        pool.release(entry2, true);

        Assert.assertTrue(future3.isDone());
        final PoolEntry<String, HttpConnection> entry3 = future3.get();
        Assert.assertNotNull(entry3);
        Assert.assertFalse(entry3.hasConnection());
        entry3.assignConnection(conn3);
        Assert.assertTrue(future4.isDone());
        final PoolEntry<String, HttpConnection> entry4 = future4.get();
        Assert.assertNotNull(entry4);
        Assert.assertFalse(entry4.hasConnection());
        entry4.assignConnection(conn4);

        totals = pool.getTotalStats();
        Assert.assertEquals(0, totals.getAvailable());
        Assert.assertEquals(2, totals.getLeased());
        Assert.assertEquals(0, totals.getPending());

        final Future<PoolEntry<String, HttpConnection>> future5 = pool.lease("somehost", null);
        final Future<PoolEntry<String, HttpConnection>> future6 = pool.lease("otherhost", null);

        pool.release(entry3, true);
        pool.release(entry4, true);

        Assert.assertTrue(future5.isDone());
        final PoolEntry<String, HttpConnection> entry5 = future5.get();
        Assert.assertNotNull(entry5);
        Assert.assertFalse(entry5.hasConnection());
        entry5.assignConnection(conn5);
        Assert.assertTrue(future6.isDone());
        final PoolEntry<String, HttpConnection> entry6 = future6.get();
        Assert.assertNotNull(entry6);
        Assert.assertTrue(entry6.hasConnection());
        Assert.assertSame(conn4, entry6.getConnection());

        totals = pool.getTotalStats();
        Assert.assertEquals(0, totals.getAvailable());
        Assert.assertEquals(2, totals.getLeased());
        Assert.assertEquals(0, totals.getPending());

        pool.release(entry5, true);
        pool.release(entry6, true);

        totals = pool.getTotalStats();
        Assert.assertEquals(2, totals.getAvailable());
        Assert.assertEquals(0, totals.getLeased());
        Assert.assertEquals(0, totals.getPending());
    }

    @Test
    public void testStatefulConnectionRedistributionOnPerRouteMaxLimit() throws Exception {
        final HttpConnection conn1 = Mockito.mock(HttpConnection.class);
        final HttpConnection conn2 = Mockito.mock(HttpConnection.class);

        final StrictConnPool<String, HttpConnection> pool = new StrictConnPool<>(2, 10);
        pool.setMaxPerRoute("somehost", 2);
        pool.setMaxTotal(2);

        final Future<PoolEntry<String, HttpConnection>> future1 = pool.lease("somehost", null);
        final Future<PoolEntry<String, HttpConnection>> future2 = pool.lease("somehost", null);

        Assert.assertTrue(future1.isDone());
        final PoolEntry<String, HttpConnection> entry1 = future1.get();
        entry1.assignConnection(conn1);
        Assert.assertNotNull(entry1);
        Assert.assertTrue(future2.isDone());
        final PoolEntry<String, HttpConnection> entry2 = future2.get();
        Assert.assertNotNull(entry2);
        entry2.assignConnection(conn2);

        PoolStats totals = pool.getTotalStats();
        Assert.assertEquals(0, totals.getAvailable());
        Assert.assertEquals(2, totals.getLeased());
        Assert.assertEquals(0, totals.getPending());

        entry1.updateState("some-stuff");
        pool.release(entry1, true);
        entry2.updateState("some-stuff");
        pool.release(entry2, true);

        final Future<PoolEntry<String, HttpConnection>> future3 = pool.lease("somehost", "some-stuff");
        final Future<PoolEntry<String, HttpConnection>> future4 = pool.lease("somehost", "some-stuff");

        Assert.assertTrue(future1.isDone());
        final PoolEntry<String, HttpConnection> entry3 = future3.get();
        Assert.assertNotNull(entry3);
        Assert.assertSame(conn2, entry3.getConnection());
        Assert.assertTrue(future4.isDone());
        final PoolEntry<String, HttpConnection> entry4 = future4.get();
        Assert.assertNotNull(entry4);
        Assert.assertSame(conn1, entry4.getConnection());

        pool.release(entry3, true);
        pool.release(entry4, true);

        totals = pool.getTotalStats();
        Assert.assertEquals(2, totals.getAvailable());
        Assert.assertEquals(0, totals.getLeased());
        Assert.assertEquals(0, totals.getPending());

        final Future<PoolEntry<String, HttpConnection>> future5 = pool.lease("somehost", "some-other-stuff");

        Assert.assertTrue(future5.isDone());

        Mockito.verify(conn2).close(CloseMode.GRACEFUL);
        Mockito.verify(conn1, Mockito.never()).close(ArgumentMatchers.<CloseMode>any());

        totals = pool.getTotalStats();
        Assert.assertEquals(1, totals.getAvailable());
        Assert.assertEquals(1, totals.getLeased());
    }

    @Test
    public void testCreateNewIfExpired() throws Exception {
        final HttpConnection conn1 = Mockito.mock(HttpConnection.class);

        final StrictConnPool<String, HttpConnection> pool = new StrictConnPool<>(2, 2);

        final Future<PoolEntry<String, HttpConnection>> future1 = pool.lease("somehost", null);

        Assert.assertTrue(future1.isDone());
        final PoolEntry<String, HttpConnection> entry1 = future1.get();
        Assert.assertNotNull(entry1);
        entry1.assignConnection(conn1);

        entry1.updateExpiry(TimeValue.of(1, TimeUnit.MILLISECONDS));
        pool.release(entry1, true);

        Thread.sleep(200L);

        final Future<PoolEntry<String, HttpConnection>> future2 = pool.lease("somehost", null);

        Assert.assertTrue(future2.isDone());

        Mockito.verify(conn1).close(CloseMode.GRACEFUL);

        final PoolStats totals = pool.getTotalStats();
        Assert.assertEquals(0, totals.getAvailable());
        Assert.assertEquals(1, totals.getLeased());
        Assert.assertEquals(Collections.singleton("somehost"), pool.getRoutes());
        final PoolStats stats = pool.getStats("somehost");
        Assert.assertEquals(0, stats.getAvailable());
        Assert.assertEquals(1, stats.getLeased());
    }

    @Test
    public void testCloseExpired() throws Exception {
        final HttpConnection conn1 = Mockito.mock(HttpConnection.class);
        final HttpConnection conn2 = Mockito.mock(HttpConnection.class);

        final StrictConnPool<String, HttpConnection> pool = new StrictConnPool<>(2, 2);

        final Future<PoolEntry<String, HttpConnection>> future1 = pool.lease("somehost", null);
        final Future<PoolEntry<String, HttpConnection>> future2 = pool.lease("somehost", null);

        Assert.assertTrue(future1.isDone());
        final PoolEntry<String, HttpConnection> entry1 = future1.get();
        Assert.assertNotNull(entry1);
        entry1.assignConnection(conn1);
        Assert.assertTrue(future2.isDone());
        final PoolEntry<String, HttpConnection> entry2 = future2.get();
        Assert.assertNotNull(entry2);
        entry2.assignConnection(conn2);

        entry1.updateExpiry(TimeValue.of(1, TimeUnit.MILLISECONDS));
        pool.release(entry1, true);

        Thread.sleep(200);

        entry2.updateExpiry(TimeValue.of(1000, TimeUnit.SECONDS));
        pool.release(entry2, true);

        pool.closeExpired();

        Mockito.verify(conn1).close(CloseMode.GRACEFUL);
        Mockito.verify(conn2, Mockito.never()).close(ArgumentMatchers.<CloseMode>any());

        final PoolStats totals = pool.getTotalStats();
        Assert.assertEquals(1, totals.getAvailable());
        Assert.assertEquals(0, totals.getLeased());
        Assert.assertEquals(0, totals.getPending());
        final PoolStats stats = pool.getStats("somehost");
        Assert.assertEquals(1, stats.getAvailable());
        Assert.assertEquals(0, stats.getLeased());
        Assert.assertEquals(0, stats.getPending());
    }

    @Test
    public void testCloseIdle() throws Exception {
        final HttpConnection conn1 = Mockito.mock(HttpConnection.class);
        final HttpConnection conn2 = Mockito.mock(HttpConnection.class);

        final StrictConnPool<String, HttpConnection> pool = new StrictConnPool<>(2, 2);

        final Future<PoolEntry<String, HttpConnection>> future1 = pool.lease("somehost", null);
        final Future<PoolEntry<String, HttpConnection>> future2 = pool.lease("somehost", null);

        Assert.assertTrue(future1.isDone());
        final PoolEntry<String, HttpConnection> entry1 = future1.get();
        Assert.assertNotNull(entry1);
        entry1.assignConnection(conn1);
        Assert.assertTrue(future2.isDone());
        final PoolEntry<String, HttpConnection> entry2 = future2.get();
        Assert.assertNotNull(entry2);
        entry2.assignConnection(conn2);

        entry1.updateState(null);
        pool.release(entry1, true);

        Thread.sleep(200L);

        entry2.updateState(null);
        pool.release(entry2, true);

        pool.closeIdle(TimeValue.of(50, TimeUnit.MILLISECONDS));

        Mockito.verify(conn1).close(CloseMode.GRACEFUL);
        Mockito.verify(conn2, Mockito.never()).close(ArgumentMatchers.<CloseMode>any());

        PoolStats totals = pool.getTotalStats();
        Assert.assertEquals(1, totals.getAvailable());
        Assert.assertEquals(0, totals.getLeased());
        Assert.assertEquals(0, totals.getPending());
        PoolStats stats = pool.getStats("somehost");
        Assert.assertEquals(1, stats.getAvailable());
        Assert.assertEquals(0, stats.getLeased());
        Assert.assertEquals(0, stats.getPending());

        pool.closeIdle(TimeValue.of(-1, TimeUnit.MILLISECONDS));

        Mockito.verify(conn2).close(CloseMode.GRACEFUL);

        totals = pool.getTotalStats();
        Assert.assertEquals(0, totals.getAvailable());
        Assert.assertEquals(0, totals.getLeased());
        Assert.assertEquals(0, totals.getPending());
        stats = pool.getStats("somehost");
        Assert.assertEquals(0, stats.getAvailable());
        Assert.assertEquals(0, stats.getLeased());
        Assert.assertEquals(0, stats.getPending());
    }

    @Test
    public void testLeaseRequestTimeout() throws Exception {
        final HttpConnection conn1 = Mockito.mock(HttpConnection.class);

        final StrictConnPool<String, HttpConnection> pool = new StrictConnPool<>(1, 1);

        final Future<PoolEntry<String, HttpConnection>> future1 = pool.lease("somehost", null, Timeout.ofMilliseconds(0), null);
        final Future<PoolEntry<String, HttpConnection>> future2 = pool.lease("somehost", null, Timeout.ofMilliseconds(0), null);
        final Future<PoolEntry<String, HttpConnection>> future3 = pool.lease("somehost", null, Timeout.ofMilliseconds(10), null);

        Assert.assertTrue(future1.isDone());
        final PoolEntry<String, HttpConnection> entry1 = future1.get();
        Assert.assertNotNull(entry1);
        entry1.assignConnection(conn1);
        Assert.assertFalse(future2.isDone());
        Assert.assertFalse(future3.isDone());

        Thread.sleep(100);

        pool.validatePendingRequests();

        Assert.assertFalse(future2.isDone());
        Assert.assertTrue(future3.isDone());
    }

    private static class HoldInternalLockThread extends Thread {
        private HoldInternalLockThread(final StrictConnPool<String, HttpConnection> pool, final CountDownLatch lockHeld) {
            super(() -> {
                pool.lease("somehost", null); // lease a connection so we have something to enumLeased()
                pool.enumLeased(object -> {
                    try {
                        lockHeld.countDown();
                        Thread.sleep(Long.MAX_VALUE);
                    } catch (final InterruptedException ignored) {
                    }
                });
            });
        }
    }

    @Test
    public void testLeaseRequestLockTimeout() throws Exception {
        final StrictConnPool<String, HttpConnection> pool = new StrictConnPool<>(1, 1);
        final CountDownLatch lockHeld = new CountDownLatch(1);
        final Thread holdInternalLock = new HoldInternalLockThread(pool, lockHeld);

        holdInternalLock.start(); // Start a thread to grab the internal conn pool lock
        lockHeld.await(); // Wait until we know the internal lock is held

        // Attempt to get a connection while lock is held
        final Future<PoolEntry<String, HttpConnection>> future2 = pool.lease("somehost", null, Timeout.ofMilliseconds(10), null);

        try {
            future2.get();
        } catch (final ExecutionException executionException) {
            Assert.assertTrue(executionException.getCause() instanceof DeadlineTimeoutException);
            holdInternalLock.interrupt(); // Cleanup
            return;
        }
        Assert.fail("Expected deadline timeout.");
    }

    @Test
    public void testLeaseRequestInterrupted() throws Exception {
        final StrictConnPool<String, HttpConnection> pool = new StrictConnPool<>(1, 1);
        final CountDownLatch lockHeld = new CountDownLatch(1);
        final Thread holdInternalLock = new HoldInternalLockThread(pool, lockHeld);

        holdInternalLock.start(); // Start a thread to grab the internal conn pool lock
        lockHeld.await(); // Wait until we know the internal lock is held

        Thread.currentThread().interrupt();
        // Attempt to get a connection while lock is held and thread is interrupted
        final Future<PoolEntry<String, HttpConnection>> future2 = pool.lease("somehost", null, Timeout.ofMilliseconds(10), null);

        Assert.assertTrue(Thread.interrupted());
        try {
            future2.get();
        } catch (final CancellationException cancellationException) {
            holdInternalLock.interrupt(); // Cleanup
            return;
        }
        Assert.fail("Expected interrupted exception.");
    }

    @Test
    public void testLeaseRequestCanceled() throws Exception {
        final StrictConnPool<String, HttpConnection> pool = new StrictConnPool<>(1, 1);

        final Future<PoolEntry<String, HttpConnection>> future1 = pool.lease("somehost", null, Timeout.ofMilliseconds(0), null);

        Assert.assertTrue(future1.isDone());
        final PoolEntry<String, HttpConnection> entry1 = future1.get();
        Assert.assertNotNull(entry1);
        entry1.assignConnection(Mockito.mock(HttpConnection.class));

        final Future<PoolEntry<String, HttpConnection>> future2 = pool.lease("somehost", null, Timeout.ofMilliseconds(0), null);
        future2.cancel(true);

        pool.release(entry1, true);

        final PoolStats totals = pool.getTotalStats();
        Assert.assertEquals(1, totals.getAvailable());
        Assert.assertEquals(0, totals.getLeased());
    }

    @Test(expected=NullPointerException.class)
    public void testGetStatsInvalid() throws Exception {
        final StrictConnPool<String, HttpConnection> pool = new StrictConnPool<>(2, 2);
        pool.getStats(null);
    }

    @Test
    public void testSetMaxInvalid() throws Exception {
        final StrictConnPool<String, HttpConnection> pool = new StrictConnPool<>(2, 2);
        try {
            pool.setMaxTotal(-1);
            Assert.fail("IllegalArgumentException should have been thrown");
        } catch (final IllegalArgumentException expected) {
        }
        try {
            pool.setMaxPerRoute(null, 1);
            Assert.fail("NullPointerException should have been thrown");
        } catch (final NullPointerException expected) {
        }
        try {
            pool.setDefaultMaxPerRoute(-1);
            Assert.fail("IllegalArgumentException should have been thrown");
        } catch (final IllegalArgumentException expected) {
        }
    }

    @Test
    public void testSetMaxPerRoute() throws Exception {
        final StrictConnPool<String, HttpConnection> pool = new StrictConnPool<>(2, 2);
        pool.setMaxPerRoute("somehost", 1);
        Assert.assertEquals(1, pool.getMaxPerRoute("somehost"));
        pool.setMaxPerRoute("somehost", 0);
        Assert.assertEquals(0, pool.getMaxPerRoute("somehost"));
        pool.setMaxPerRoute("somehost", -1);
        Assert.assertEquals(2, pool.getMaxPerRoute("somehost"));
    }

    @Test
    public void testShutdown() throws Exception {
        final StrictConnPool<String, HttpConnection> pool = new StrictConnPool<>(2, 2);
        pool.close(CloseMode.GRACEFUL);
        try {
            pool.lease("somehost", null);
            Assert.fail("IllegalStateException should have been thrown");
        } catch (final IllegalStateException expected) {
        }
        // Ignored if shut down
        pool.release(new PoolEntry<>("somehost"), true);
    }

}