HHH-5409 - bag and idbag should implement equals() and hashCode() the same way as other collections

This test does not verify how equals is implemented for Bags,
but rather if the child entity equals and hashCode are used properly for both
managed and detached entities.

hibernate-core/src/test/java/org/hibernate/test/collection/bag/PersistentBagContainsTest.java

@@ -0,0 +1,167 @@
+/*
+ * Hibernate, Relational Persistence for Idiomatic Java
+ *
+ * License: GNU Lesser General Public License (LGPL), version 2.1 or later.
+ * See the lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>.
+ */
+package org.hibernate.test.collection.bag;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Objects;
+import javax.persistence.CascadeType;
+import javax.persistence.Entity;
+import javax.persistence.GeneratedValue;
+import javax.persistence.Id;
+import javax.persistence.ManyToOne;
+import javax.persistence.OneToMany;
+
+import org.hibernate.testing.TestForIssue;
+import org.hibernate.testing.junit4.BaseCoreFunctionalTestCase;
+import org.junit.Test;
+
+import static org.hibernate.testing.transaction.TransactionUtil.doInHibernate;
+import static org.wildfly.common.Assert.assertTrue;
+
+/**
+ * Tests related to contains operations on a PersistentBag.
+ *
+ * @author Vlad Mihalcea
+ */
+public class PersistentBagContainsTest extends BaseCoreFunctionalTestCase {
+
+	@Override
+	protected Class<?>[] getAnnotatedClasses() {
+		return new Class[] {
+			Order.class,
+			Item.class
+		};
+	}
+
+	/**
+	 * This test does not verify how equals is implemented for Bags,
+	 * but rather if the child entity equals and hashCode are used properly for both
+	 * managed and detached entities.
+	 */
+	@Test
+	@TestForIssue( jiraKey = "HHH-5409")
+	public void testContains() {
+		Order _order = doInHibernate( this::sessionFactory, session -> {
+			Order order = new Order();
+			session.persist( order );
+
+			Item item1 = new Item();
+			item1.setName( "i1" );
+			Item item2 = new Item();
+			item2.setName( "i2" );
+			order.addItem( item1 );
+			order.addItem( item2 );
+
+			return order;
+		} );
+
+		doInHibernate( this::sessionFactory, session -> {
+			Item item1 = new Item();
+			item1.setName( "i1" );
+
+			Item item2 = new Item();
+			item2.setName( "i2" );
+
+			assertTrue(_order.getItems().contains( item1 ));
+			assertTrue(_order.getItems().contains( item2 ));
+
+			Order order = session.find( Order.class, _order.getId() );
+
+			assertTrue(order.getItems().contains( item1 ));
+			assertTrue(order.getItems().contains( item2 ));
+		} );
+
+		doInHibernate( this::sessionFactory, session -> {
+			Order order = session.find( Order.class, _order.getId() );
+			session.delete( order );
+		} );
+	}
+
+	@Entity(name = "`Order`")
+	public static class Order {
+
+		@Id
+		@GeneratedValue
+		private Long id;
+
+		@OneToMany(mappedBy = "order", cascade = CascadeType.ALL, orphanRemoval = true)
+		private List<Item> items = new ArrayList<Item>();
+
+		public Long getId() {
+			return id;
+		}
+
+		public void setId(Long id) {
+			this.id = id;
+		}
+
+		public List<Item> getItems() {
+			return items;
+		}
+
+		public void addItem(Item item) {
+			items.add( item );
+			item.setOrder( this );
+		}
+	}
+
+	@Entity(name = "Item")
+	public static class Item {
+
+		@Id
+		@GeneratedValue
+		private Long id;
+
+		private String name;
+
+		@ManyToOne
+		private Order order;
+
+		public Long getId() {
+			return id;
+		}
+
+		public void setId(Long id) {
+			this.id = id;
+		}
+
+		public String getName() {
+			return name;
+		}
+
+		public void setName(String name) {
+			this.name = name;
+		}
+
+		public Order getOrder() {
+			return order;
+		}
+
+		public void setOrder(Order order) {
+			this.order = order;
+		}
+
+		@Override
+		public boolean equals(Object o) {
+			if ( this == o ) {
+				return true;
+			}
+			if ( !( o instanceof Item ) ) {
+				return false;
+			}
+			Item item = (Item) o;
+			return Objects.equals( getName(), item.getName() );
+		}
+
+		@Override
+		public int hashCode() {
+			return Objects.hash( getName() );
+		}
+	}
+
+}