Add treat test for TCK compliance

hibernate-core/src/test/java/org/hibernate/orm/test/query/hql/treat/HqlTreatTest.java

@@ -0,0 +1,132 @@
+/*
+ * 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.orm.test.query.hql.treat;
+
+import java.util.List;
+
+import org.hibernate.testing.orm.junit.EntityManagerFactoryScope;
+import org.hibernate.testing.orm.junit.Jpa;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import jakarta.persistence.DiscriminatorColumn;
+import jakarta.persistence.DiscriminatorType;
+import jakarta.persistence.DiscriminatorValue;
+import jakarta.persistence.Entity;
+import jakarta.persistence.Id;
+import jakarta.persistence.Inheritance;
+import jakarta.persistence.InheritanceType;
+import jakarta.persistence.ManyToOne;
+import jakarta.persistence.PrimaryKeyJoinColumn;
+import jakarta.persistence.SecondaryTable;
+import jakarta.persistence.SecondaryTables;
+import jakarta.persistence.Table;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+
+@Jpa(
+		annotatedClasses = {
+				HqlTreatTest.Product.class,
+				HqlTreatTest.SoftwareProduct.class,
+				HqlTreatTest.LineItem.class
+		}
+)
+public class HqlTreatTest {
+
+
+	@BeforeEach
+	public void setUp(EntityManagerFactoryScope scope) {
+		scope.inTransaction(
+				entityManager -> {
+					Product product1 = new Product( 1, "Monitor" );
+					Product product2 = new SoftwareProduct( 2, "Linux" );
+					LineItem lineItem1 = new LineItem( 1, 3, product1 );
+					LineItem lineItem2 = new LineItem( 2, 5, product2 );
+					entityManager.persist( product1 );
+					entityManager.persist( product2 );
+					entityManager.persist( lineItem1 );
+					entityManager.persist( lineItem2 );
+				}
+		);
+	}
+
+
+	@Test
+	public void treatJoinClassTest(EntityManagerFactoryScope scope) {
+
+		scope.inTransaction(
+				entityManager -> {
+					List<String> names = entityManager.createQuery(
+									"SELECT s.name FROM LineItem l JOIN TREAT(l.product AS SoftwareProduct) s" )
+							.getResultList();
+					assertEquals( 1, names.size() );
+					assertEquals( "Linux", names.get( 0 ) );
+				}
+		);
+	}
+
+
+	@Entity(name = "LineItem")
+	@Table(name = "LINEITEM_TABLE")
+	public static class LineItem {
+
+		@Id
+		private Integer id;
+
+		private int quantity;
+
+		@ManyToOne
+		private Product product;
+
+		public LineItem() {
+		}
+
+		public LineItem(Integer id, int quantity, Product product) {
+			this.id = id;
+			this.quantity = quantity;
+			this.product = product;
+		}
+	}
+
+	@Entity(name = "Product")
+	@Table(name = "PRODUCT_TABLE")
+	@SecondaryTables({
+			@SecondaryTable(name = "PRODUCT_DETAILS", pkJoinColumns = @PrimaryKeyJoinColumn(name = "ID"))
+	})
+	@Inheritance(strategy = InheritanceType.SINGLE_TABLE)
+	@DiscriminatorColumn(name = "PRODUCT_TYPE", discriminatorType = DiscriminatorType.STRING)
+	@DiscriminatorValue("Product")
+	public static class Product {
+
+		@Id
+		private Integer id;
+
+		private String name;
+
+		public Product() {
+		}
+
+		public Product(Integer id, String name) {
+			this.id = id;
+			this.name = name;
+		}
+	}
+
+	@Entity(name = "SoftwareProduct")
+	@DiscriminatorValue("SW")
+	public static class SoftwareProduct extends Product {
+
+		public SoftwareProduct() {
+		}
+
+		public SoftwareProduct(Integer id, String name) {
+			super( id, name );
+		}
+	}
+
+}