/*
    * 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.commons.pool2;
  
  import static org.junit.jupiter.api.Assertions.assertEquals;
  import static org.junit.jupiter.api.Assertions.assertThrows;
  import static org.junit.jupiter.api.Assertions.fail;
  
  import java.util.ArrayList;
  import java.util.List;
  import java.util.NoSuchElementException;
  
  import org.apache.commons.pool2.impl.DefaultPooledObject;
  import org.apache.commons.pool2.impl.GenericKeyedObjectPool;
  import org.junit.jupiter.api.AfterEach;
  import org.junit.jupiter.api.Test;
  
  /**
   * Abstract test case for {@link ObjectPool} implementations.
   */
  public abstract class AbstractTestKeyedObjectPool {
  
      protected static class FailingKeyedPooledObjectFactory implements KeyedPooledObjectFactory<Object, Object> {
          private final List<MethodCall> methodCalls = new ArrayList<>();
          private int count;
          private boolean makeObjectFail;
          private boolean activateObjectFail;
          private boolean validateObjectFail;
          private boolean passivateObjectFail;
          private boolean destroyObjectFail;
  
          public FailingKeyedPooledObjectFactory() {
          }
  
          @Override
          public void activateObject(final Object key, final PooledObject<Object> obj) {
              methodCalls.add(new MethodCall("activateObject", key, obj.getObject()));
              if (activateObjectFail) {
                  throw new PrivateException("activateObject");
              }
          }
  
          @Override
          public void destroyObject(final Object key, final PooledObject<Object> obj) {
              methodCalls.add(new MethodCall("destroyObject", key, obj.getObject()));
              if (destroyObjectFail) {
                  throw new PrivateException("destroyObject");
              }
          }
  
          public int getCurrentCount() {
              return count;
          }
  
          public List<MethodCall> getMethodCalls() {
              return methodCalls;
          }
  
          public boolean isActivateObjectFail() {
              return activateObjectFail;
          }
  
          public boolean isDestroyObjectFail() {
              return destroyObjectFail;
          }
  
          public boolean isMakeObjectFail() {
              return makeObjectFail;
          }
  
          public boolean isPassivateObjectFail() {
              return passivateObjectFail;
          }
  
          public boolean isValidateObjectFail() {
              return validateObjectFail;
          }
  
          @Override
          public PooledObject<Object> makeObject(final Object key) {
              final MethodCall call = new MethodCall("makeObject", key);
              methodCalls.add(call);
              final int originalCount = this.count++;
              if (makeObjectFail) {
                  throw new PrivateException("makeObject");
             }
             // Deliberate choice to create new object in case future unit test
             // checks for a specific object
             final Integer obj = Integer.valueOf(originalCount);
             call.setReturned(obj);
             return new DefaultPooledObject<>(obj);
         }
 
         @Override
         public void passivateObject(final Object key, final PooledObject<Object> obj) {
             methodCalls.add(new MethodCall("passivateObject", key, obj.getObject()));
             if (passivateObjectFail) {
                 throw new PrivateException("passivateObject");
             }
         }
 
         public void reset() {
             count = 0;
             getMethodCalls().clear();
             setMakeObjectFail(false);
             setActivateObjectFail(false);
             setValidateObjectFail(false);
             setPassivateObjectFail(false);
             setDestroyObjectFail(false);
         }
 
         public void setActivateObjectFail(final boolean activateObjectFail) {
             this.activateObjectFail = activateObjectFail;
         }
 
         public void setCurrentCount(final int count) {
             this.count = count;
         }
 
         public void setDestroyObjectFail(final boolean destroyObjectFail) {
             this.destroyObjectFail = destroyObjectFail;
         }
 
         public void setMakeObjectFail(final boolean makeObjectFail) {
             this.makeObjectFail = makeObjectFail;
         }
 
         public void setPassivateObjectFail(final boolean passivateObjectFail) {
             this.passivateObjectFail = passivateObjectFail;
         }
 
         public void setValidateObjectFail(final boolean validateObjectFail) {
             this.validateObjectFail = validateObjectFail;
         }
 
         @Override
         public boolean validateObject(final Object key, final PooledObject<Object> obj) {
             final MethodCall call = new MethodCall("validateObject", key, obj.getObject());
             methodCalls.add(call);
             if (validateObjectFail) {
                 throw new PrivateException("validateObject");
             }
             final boolean r = true;
             call.returned(Boolean.valueOf(r));
             return r;
         }
     }
 
     private static final class TestFactory extends BaseKeyedPooledObjectFactory<Object, Object> {
         @Override
         public Object create(final Object key) {
             return new Object();
         }
 
         @Override
         public PooledObject<Object> wrap(final Object value) {
             return new DefaultPooledObject<>(value);
         }
     }
 
     protected static final String KEY = "key";
 
     private KeyedObjectPool<Object, Object> pool;
 
     // Deliberate choice to create a new object in case future unit tests check
     // for a specific object.
     private final Integer ZERO = Integer.valueOf(0);
 
     private final Integer ONE = Integer.valueOf(1);
 
     private void clear(final FailingKeyedPooledObjectFactory factory, final List<MethodCall> expectedMethods) {
         factory.getMethodCalls().clear();
         expectedMethods.clear();
     }
 
     /**
      * Return what we expect to be the n<sup>th</sup>
      * object (zero indexed) created by the pool
      * for the given key.
      *
      * @param key Key for the object to be obtained
      * @param n   index of the object to be obtained
      * @return the requested object
      */
     protected abstract Object getNthObject(Object key, int n);
 
     protected abstract boolean isFifo();
 
     protected abstract boolean isLifo();
 
     /**
      * Creates an {@link KeyedObjectPool} instance
      * that can contain at least <em>minCapacity</em>
      * idle and active objects, or
      * throw {@link IllegalArgumentException}
      * if such a pool cannot be created.
      *
      * @param minCapacity Minimum capacity of the pool to create
      * @return the newly created keyed object pool
      */
     protected abstract <E extends Exception> KeyedObjectPool<Object, Object> makeEmptyPool(int minCapacity);
 
     /**
      * Creates an {@code KeyedObjectPool} with the specified factory.
      * The pool should be in a default configuration and conform to the expected
      * behaviors described in {@link KeyedObjectPool}.
      * Generally speaking there should be no limits on the various object counts.
      *
      * @param <E>     The type of exception thrown by the pool
      * @param factory Factory to use to associate with the pool
      * @return The newly created empty pool
      */
     protected abstract <E extends Exception> KeyedObjectPool<Object, Object> makeEmptyPool(
             KeyedPooledObjectFactory<Object, Object> factory);
 
     protected abstract Object makeKey(int n);
 
     private <E extends Exception> void reset(final KeyedObjectPool<Object, Object> pool,
             final FailingKeyedPooledObjectFactory factory,
             final List<MethodCall> expectedMethods) throws Exception {
         pool.clear();
         clear(factory, expectedMethods);
         factory.reset();
     }
 
     @AfterEach
     public void tearDown() {
         pool = null;
     }
 
     @Test
     public void testBaseAddObject() throws Exception {
         try {
             pool = makeEmptyPool(3);
         } catch (final UnsupportedOperationException uoe) {
             return; // skip this test if unsupported
         }
         final Object key = makeKey(0);
         try {
             assertEquals(0, pool.getNumIdle());
             assertEquals(0, pool.getNumActive());
             assertEquals(0, pool.getNumIdle(key));
             assertEquals(0, pool.getNumActive(key));
             pool.addObject(key);
             assertEquals(1, pool.getNumIdle());
             assertEquals(0, pool.getNumActive());
             assertEquals(1, pool.getNumIdle(key));
             assertEquals(0, pool.getNumActive(key));
             final Object obj = pool.borrowObject(key);
             assertEquals(getNthObject(key, 0), obj);
             assertEquals(0, pool.getNumIdle());
             assertEquals(1, pool.getNumActive());
             assertEquals(0, pool.getNumIdle(key));
             assertEquals(1, pool.getNumActive(key));
             pool.returnObject(key, obj);
             assertEquals(1, pool.getNumIdle());
             assertEquals(0, pool.getNumActive());
             assertEquals(1, pool.getNumIdle(key));
             assertEquals(0, pool.getNumActive(key));
         } catch (final UnsupportedOperationException e) {
             return; // skip this test if one of those calls is unsupported
         } finally {
             pool.close();
         }
     }
 
     @Test
     public void testBaseBorrow() throws Exception {
         try {
             pool = makeEmptyPool(3);
         } catch (final UnsupportedOperationException uoe) {
             return; // skip this test if unsupported
         }
         final Object keya = makeKey(0);
         final Object keyb = makeKey(1);
         assertEquals(getNthObject(keya, 0), pool.borrowObject(keya), "1");
         assertEquals(getNthObject(keyb, 0), pool.borrowObject(keyb), "2");
         assertEquals(getNthObject(keyb, 1), pool.borrowObject(keyb), "3");
         assertEquals(getNthObject(keya, 1), pool.borrowObject(keya), "4");
         assertEquals(getNthObject(keyb, 2), pool.borrowObject(keyb), "5");
         assertEquals(getNthObject(keya, 2), pool.borrowObject(keya), "6");
         pool.close();
     }
 
     @Test
     public void testBaseBorrowReturn() throws Exception {
         try {
             pool = makeEmptyPool(3);
         } catch (final UnsupportedOperationException uoe) {
             return; // skip this test if unsupported
         }
         final Object keya = makeKey(0);
         Object obj0 = pool.borrowObject(keya);
         assertEquals(getNthObject(keya, 0), obj0);
         Object obj1 = pool.borrowObject(keya);
         assertEquals(getNthObject(keya, 1), obj1);
         Object obj2 = pool.borrowObject(keya);
         assertEquals(getNthObject(keya, 2), obj2);
         pool.returnObject(keya, obj2);
         obj2 = pool.borrowObject(keya);
         assertEquals(getNthObject(keya, 2), obj2);
         pool.returnObject(keya, obj1);
         obj1 = pool.borrowObject(keya);
         assertEquals(getNthObject(keya, 1), obj1);
         pool.returnObject(keya, obj0);
         pool.returnObject(keya, obj2);
         obj2 = pool.borrowObject(keya);
         if (isLifo()) {
             assertEquals(getNthObject(keya, 2), obj2);
         }
         if (isFifo()) {
             assertEquals(getNthObject(keya, 0), obj2);
         }
         obj0 = pool.borrowObject(keya);
         if (isLifo()) {
             assertEquals(getNthObject(keya, 0), obj0);
         }
         if (isFifo()) {
             assertEquals(getNthObject(keya, 2), obj0);
         }
         pool.close();
     }
 
     @Test
     public void testBaseClear() throws Exception {
         try {
             pool = makeEmptyPool(3);
         } catch (final UnsupportedOperationException uoe) {
             return; // skip this test if unsupported
         }
         final Object keya = makeKey(0);
         assertEquals(0, pool.getNumActive(keya));
         assertEquals(0, pool.getNumIdle(keya));
         final Object obj0 = pool.borrowObject(keya);
         final Object obj1 = pool.borrowObject(keya);
         assertEquals(2, pool.getNumActive(keya));
         assertEquals(0, pool.getNumIdle(keya));
         pool.returnObject(keya, obj1);
         pool.returnObject(keya, obj0);
         assertEquals(0, pool.getNumActive(keya));
         assertEquals(2, pool.getNumIdle(keya));
         pool.clear(keya);
         assertEquals(0, pool.getNumActive(keya));
         assertEquals(0, pool.getNumIdle(keya));
         final Object obj2 = pool.borrowObject(keya);
         assertEquals(getNthObject(keya, 2), obj2);
         pool.close();
     }
 
     @Test
     public void testBaseInvalidateObject() throws Exception {
         try {
             pool = makeEmptyPool(3);
         } catch (final UnsupportedOperationException uoe) {
             return; // skip this test if unsupported
         }
         final Object keya = makeKey(0);
         assertEquals(0, pool.getNumActive(keya));
         assertEquals(0, pool.getNumIdle(keya));
         final Object obj0 = pool.borrowObject(keya);
         final Object obj1 = pool.borrowObject(keya);
         assertEquals(2, pool.getNumActive(keya));
         assertEquals(0, pool.getNumIdle(keya));
         pool.invalidateObject(keya, obj0);
         assertEquals(1, pool.getNumActive(keya));
         assertEquals(0, pool.getNumIdle(keya));
         pool.invalidateObject(keya, obj1);
         assertEquals(0, pool.getNumActive(keya));
         assertEquals(0, pool.getNumIdle(keya));
         pool.close();
     }
 
     @Test
     public void testBaseNumActiveNumIdle() throws Exception {
         try {
             pool = makeEmptyPool(3);
         } catch (final UnsupportedOperationException uoe) {
             return; // skip this test if unsupported
         }
         final Object keya = makeKey(0);
         assertEquals(0, pool.getNumActive(keya));
         assertEquals(0, pool.getNumIdle(keya));
         final Object obj0 = pool.borrowObject(keya);
         assertEquals(1, pool.getNumActive(keya));
         assertEquals(0, pool.getNumIdle(keya));
         final Object obj1 = pool.borrowObject(keya);
         assertEquals(2, pool.getNumActive(keya));
         assertEquals(0, pool.getNumIdle(keya));
         pool.returnObject(keya, obj1);
         assertEquals(1, pool.getNumActive(keya));
         assertEquals(1, pool.getNumIdle(keya));
         pool.returnObject(keya, obj0);
         assertEquals(0, pool.getNumActive(keya));
         assertEquals(2, pool.getNumIdle(keya));
 
         assertEquals(0, pool.getNumActive("xyzzy12345"));
         assertEquals(0, pool.getNumIdle("xyzzy12345"));
 
         pool.close();
     }
 
     @Test
     public void testBaseNumActiveNumIdle2() throws Exception {
         try {
             pool = makeEmptyPool(6);
         } catch (final UnsupportedOperationException uoe) {
             return; // skip this test if unsupported
         }
         final Object keya = makeKey(0);
         final Object keyb = makeKey(1);
         assertEquals(0, pool.getNumActive());
         assertEquals(0, pool.getNumIdle());
         assertEquals(0, pool.getNumActive(keya));
         assertEquals(0, pool.getNumIdle(keya));
         assertEquals(0, pool.getNumActive(keyb));
         assertEquals(0, pool.getNumIdle(keyb));
 
         final Object objA0 = pool.borrowObject(keya);
         final Object objB0 = pool.borrowObject(keyb);
 
         assertEquals(2, pool.getNumActive());
         assertEquals(0, pool.getNumIdle());
         assertEquals(1, pool.getNumActive(keya));
         assertEquals(0, pool.getNumIdle(keya));
         assertEquals(1, pool.getNumActive(keyb));
         assertEquals(0, pool.getNumIdle(keyb));
 
         final Object objA1 = pool.borrowObject(keya);
         final Object objB1 = pool.borrowObject(keyb);
 
         assertEquals(4, pool.getNumActive());
         assertEquals(0, pool.getNumIdle());
         assertEquals(2, pool.getNumActive(keya));
         assertEquals(0, pool.getNumIdle(keya));
         assertEquals(2, pool.getNumActive(keyb));
         assertEquals(0, pool.getNumIdle(keyb));
 
         pool.returnObject(keya, objA0);
         pool.returnObject(keyb, objB0);
 
         assertEquals(2, pool.getNumActive());
         assertEquals(2, pool.getNumIdle());
         assertEquals(1, pool.getNumActive(keya));
         assertEquals(1, pool.getNumIdle(keya));
         assertEquals(1, pool.getNumActive(keyb));
         assertEquals(1, pool.getNumIdle(keyb));
 
         pool.returnObject(keya, objA1);
         pool.returnObject(keyb, objB1);
 
         assertEquals(0, pool.getNumActive());
         assertEquals(4, pool.getNumIdle());
         assertEquals(0, pool.getNumActive(keya));
         assertEquals(2, pool.getNumIdle(keya));
         assertEquals(0, pool.getNumActive(keyb));
         assertEquals(2, pool.getNumIdle(keyb));
 
         pool.close();
     }
 
     @Test
     public void testClosedPoolBehavior() throws Exception {
         final KeyedObjectPool<Object, Object> pool;
         try {
             pool = makeEmptyPool(new TestFactory());
         } catch (final UnsupportedOperationException uoe) {
             return; // test not supported
         }
 
         final Object o1 = pool.borrowObject(KEY);
         final Object o2 = pool.borrowObject(KEY);
 
         pool.close();
 
         assertThrows(IllegalStateException.class, () -> pool.addObject(KEY),
                 "A closed pool must throw an IllegalStateException when addObject is called.");
 
         assertThrows(IllegalStateException.class, () -> pool.borrowObject(KEY),
                 "A closed pool must throw an IllegalStateException when borrowObject is called.");
 
         // The following should not throw exceptions just because the pool is closed.
         assertEquals(0, pool.getNumIdle(KEY), "A closed pool shouldn't have any idle objects.");
         assertEquals(0, pool.getNumIdle(), "A closed pool shouldn't have any idle objects.");
         pool.getNumActive();
         pool.getNumActive(KEY);
         pool.returnObject(KEY, o1);
         assertEquals(0, pool.getNumIdle(KEY),
                 "returnObject should not add items back into the idle object pool for a closed pool.");
         assertEquals(0, pool.getNumIdle(),
                 "returnObject should not add items back into the idle object pool for a closed pool.");
         pool.invalidateObject(KEY, o2);
         pool.clear(KEY);
         pool.clear();
         pool.close();
     }
 
     @Test
     public void testKPOFAddObjectUsage() throws Exception {
         final FailingKeyedPooledObjectFactory factory = new FailingKeyedPooledObjectFactory();
         final KeyedObjectPool<Object, Object> pool;
         try {
             pool = makeEmptyPool(factory);
         } catch (final UnsupportedOperationException uoe) {
             return; // test not supported
         }
         final List<MethodCall> expectedMethods = new ArrayList<>();
 
         // addObject should make a new object, passivate it and put it in the pool
         pool.addObject(KEY);
         expectedMethods.add(new MethodCall("makeObject", KEY).returned(ZERO));
         expectedMethods.add(new MethodCall("passivateObject", KEY, ZERO));
         assertEquals(expectedMethods, factory.getMethodCalls());
 
         // Test exception handling of addObject
         reset(pool, factory, expectedMethods);
 
         // makeObject Exceptions should be propagated to client code from addObject
         factory.setMakeObjectFail(true);
         assertThrows(PrivateException.class, () -> pool.addObject(KEY),
                 "Expected addObject to propagate makeObject exception.");
         expectedMethods.add(new MethodCall("makeObject", KEY));
         assertEquals(expectedMethods, factory.getMethodCalls());
 
         clear(factory, expectedMethods);
 
         // passivateObject Exceptions should be propagated to client code from addObject
         factory.setMakeObjectFail(false);
         factory.setPassivateObjectFail(true);
         assertThrows(PrivateException.class, () -> pool.addObject(KEY),
                 "Expected addObject to propagate passivateObject exception.");
         expectedMethods.add(new MethodCall("makeObject", KEY).returned(ONE));
         expectedMethods.add(new MethodCall("passivateObject", KEY, ONE));
         assertEquals(expectedMethods, factory.getMethodCalls());
         pool.close();
     }
 
     @Test
     public void testKPOFBorrowObjectUsages() throws Exception {
         final FailingKeyedPooledObjectFactory factory = new FailingKeyedPooledObjectFactory();
         final KeyedObjectPool<Object, Object> pool;
         try {
             pool = makeEmptyPool(factory);
         } catch (final UnsupportedOperationException uoe) {
             return; // test not supported
         }
         final List<MethodCall> expectedMethods = new ArrayList<>();
         Object obj;
 
         if (pool instanceof GenericKeyedObjectPool) {
             ((GenericKeyedObjectPool<Object, Object>) pool).setTestOnBorrow(true);
         }
 
         // Test correct behavior code paths
 
         // existing idle object should be activated and validated
         pool.addObject(KEY);
         clear(factory, expectedMethods);
         obj = pool.borrowObject(KEY);
         expectedMethods.add(new MethodCall("activateObject", KEY, ZERO));
         expectedMethods.add(new MethodCall("validateObject", KEY, ZERO).returned(Boolean.TRUE));
         assertEquals(expectedMethods, factory.getMethodCalls());
         pool.returnObject(KEY, obj);
 
         // Test exception handling of borrowObject
         reset(pool, factory, expectedMethods);
 
         // makeObject Exceptions should be propagated to client code from borrowObject
         factory.setMakeObjectFail(true);
         assertThrows(PrivateException.class, () -> pool.borrowObject(KEY),
                 "Expected borrowObject to propagate makeObject exception.");
         expectedMethods.add(new MethodCall("makeObject", KEY));
         assertEquals(expectedMethods, factory.getMethodCalls());
 
         // when activateObject fails in borrowObject, a new object should be
         // borrowed/created
         reset(pool, factory, expectedMethods);
         pool.addObject(KEY);
         clear(factory, expectedMethods);
 
         factory.setActivateObjectFail(true);
         expectedMethods.add(new MethodCall("activateObject", KEY, obj));
         assertThrows(NoSuchElementException.class, () -> pool.borrowObject(KEY));
         // After idle object fails validation, new on is created and activation
         // fails again for the new one.
         expectedMethods.add(new MethodCall("makeObject", KEY).returned(ONE));
         expectedMethods.add(new MethodCall("activateObject", KEY, ONE));
         AbstractTestObjectPool.removeDestroyObjectCall(factory.getMethodCalls()); // The exact timing of destroyObject
                                                                                   // is flexible here.
         assertEquals(expectedMethods, factory.getMethodCalls());
 
         // when validateObject fails in borrowObject, a new object should be
         // borrowed/created
         reset(pool, factory, expectedMethods);
         pool.addObject(KEY);
         clear(factory, expectedMethods);
 
         factory.setValidateObjectFail(true);
         // testOnBorrow is on, so this will throw when the newly created instance
         // fails validation
         assertThrows(NoSuchElementException.class, () -> pool.borrowObject(KEY));
         // Activate, then validate for idle instance
         expectedMethods.add(new MethodCall("activateObject", KEY, ZERO));
         expectedMethods.add(new MethodCall("validateObject", KEY, ZERO));
         // Make new instance, activate succeeds, validate fails
         expectedMethods.add(new MethodCall("makeObject", KEY).returned(ONE));
         expectedMethods.add(new MethodCall("activateObject", KEY, ONE));
         expectedMethods.add(new MethodCall("validateObject", KEY, ONE));
         AbstractTestObjectPool.removeDestroyObjectCall(factory.getMethodCalls());
         assertEquals(expectedMethods, factory.getMethodCalls());
         pool.close();
     }
 
     @Test
     public void testKPOFClearUsages() throws Exception {
         final FailingKeyedPooledObjectFactory factory = new FailingKeyedPooledObjectFactory();
         final KeyedObjectPool<Object, Object> pool;
         try {
             pool = makeEmptyPool(factory);
         } catch (final UnsupportedOperationException uoe) {
             return; // test not supported
         }
         final List<MethodCall> expectedMethods = new ArrayList<>();
 
         // Test correct behavior code paths
         pool.addObjects(KEY, 5);
         pool.clear();
 
         // Test exception handling clear should swallow destroy object failures
         reset(pool, factory, expectedMethods);
         factory.setDestroyObjectFail(true);
         pool.addObjects(KEY, 5);
         pool.clear();
         pool.close();
     }
 
     @Test
     public void testKPOFCloseUsages() throws Exception {
         final FailingKeyedPooledObjectFactory factory = new FailingKeyedPooledObjectFactory();
         KeyedObjectPool<Object, Object> pool;
         try {
             pool = makeEmptyPool(factory);
         } catch (final UnsupportedOperationException uoe) {
             return; // test not supported
         }
         final List<MethodCall> expectedMethods = new ArrayList<>();
 
         // Test correct behavior code paths
         pool.addObjects(KEY, 5);
         pool.close();
 
         // Test exception handling close should swallow failures
         try (final KeyedObjectPool<Object, Object> pool2 = makeEmptyPool(factory)) {
             reset(pool2, factory, expectedMethods);
             factory.setDestroyObjectFail(true);
             pool2.addObjects(KEY, 5);
         }
     }
 
     @Test
     public void testKPOFInvalidateObjectUsages() throws Exception {
         final FailingKeyedPooledObjectFactory factory = new FailingKeyedPooledObjectFactory();
         final KeyedObjectPool<Object, Object> pool;
         try {
             pool = makeEmptyPool(factory);
         } catch (final UnsupportedOperationException uoe) {
             return; // test not supported
         }
         final List<MethodCall> expectedMethods = new ArrayList<>();
         Object obj;
 
         // Test correct behavior code paths
 
         obj = pool.borrowObject(KEY);
         clear(factory, expectedMethods);
 
         // invalidated object should be destroyed
         pool.invalidateObject(KEY, obj);
         expectedMethods.add(new MethodCall("destroyObject", KEY, obj));
         assertEquals(expectedMethods, factory.getMethodCalls());
 
         // Test exception handling of invalidateObject
         reset(pool, factory, expectedMethods);
         final Object obj2 = pool.borrowObject(KEY);
         clear(factory, expectedMethods);
         factory.setDestroyObjectFail(true);
         assertThrows(PrivateException.class, () -> pool.invalidateObject(KEY, obj2),
                 "Expecting destroy exception to propagate");
         Thread.sleep(250); // could be defered
         AbstractTestObjectPool.removeDestroyObjectCall(factory.getMethodCalls());
         assertEquals(expectedMethods, factory.getMethodCalls());
         pool.close();
     }
 
     @Test
     public void testKPOFReturnObjectUsages() throws Exception {
         final FailingKeyedPooledObjectFactory factory = new FailingKeyedPooledObjectFactory();
         final KeyedObjectPool<Object, Object> pool;
         try {
             pool = makeEmptyPool(factory);
         } catch (final UnsupportedOperationException uoe) {
             return; // test not supported
         }
         final List<MethodCall> expectedMethods = new ArrayList<>();
         Object obj;
 
         // Test correct behavior code paths
         obj = pool.borrowObject(KEY);
         clear(factory, expectedMethods);
 
         // returned object should be passivated
         pool.returnObject(KEY, obj);
         expectedMethods.add(new MethodCall("passivateObject", KEY, obj));
         assertEquals(expectedMethods, factory.getMethodCalls());
 
         // Test exception handling of returnObject
         reset(pool, factory, expectedMethods);
 
         // passivateObject should swallow exceptions and not add the object to the pool
         pool.addObject(KEY);
         pool.addObject(KEY);
         pool.addObject(KEY);
         assertEquals(3, pool.getNumIdle(KEY));
         obj = pool.borrowObject(KEY);
         obj = pool.borrowObject(KEY);
         assertEquals(1, pool.getNumIdle(KEY));
         assertEquals(2, pool.getNumActive(KEY));
         clear(factory, expectedMethods);
         factory.setPassivateObjectFail(true);
         pool.returnObject(KEY, obj);
         expectedMethods.add(new MethodCall("passivateObject", KEY, obj));
         AbstractTestObjectPool.removeDestroyObjectCall(factory.getMethodCalls()); // The exact timing of destroyObject
                                                                                   // is flexible here.
         assertEquals(expectedMethods, factory.getMethodCalls());
         assertEquals(1, pool.getNumIdle(KEY)); // Not added
         assertEquals(1, pool.getNumActive(KEY)); // But not active
 
         reset(pool, factory, expectedMethods);
         obj = pool.borrowObject(KEY);
         clear(factory, expectedMethods);
         factory.setPassivateObjectFail(true);
         factory.setDestroyObjectFail(true);
         try {
             pool.returnObject(KEY, obj);
             if (!(pool instanceof GenericKeyedObjectPool)) { // ugh, 1.3-compat
                 fail("Expecting destroyObject exception to be propagated");
             }
         } catch (final PrivateException ex) {
             // Expected
         }
         pool.close();
     }
 
     @Test
     public void testToString() {
         final FailingKeyedPooledObjectFactory factory = new FailingKeyedPooledObjectFactory();
         try (final KeyedObjectPool<Object, Object> pool = makeEmptyPool(factory)) {
             pool.toString();
         } catch (final UnsupportedOperationException uoe) {
             return; // test not supported
         }
     }
 }