HHH-18439 Add test for issue

Author: mbellade

hibernate-core/src/test/java/org/hibernate/orm/test/querycache/QueryCacheNullValueTest.java

@@ -0,0 +1,77 @@
+/*
+ * 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.querycache;
+
+import org.hibernate.cfg.AvailableSettings;
+import org.hibernate.stat.spi.StatisticsImplementor;
+
+import org.hibernate.testing.orm.domain.gambit.BasicEntity;
+import org.hibernate.testing.orm.junit.DomainModel;
+import org.hibernate.testing.orm.junit.Jira;
+import org.hibernate.testing.orm.junit.ServiceRegistry;
+import org.hibernate.testing.orm.junit.SessionFactory;
+import org.hibernate.testing.orm.junit.SessionFactoryScope;
+import org.hibernate.testing.orm.junit.Setting;
+import org.junit.jupiter.api.AfterAll;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * @author Marco Belladelli
+ */
+@DomainModel( annotatedClasses = {
+		BasicEntity.class
+} )
+@SessionFactory( generateStatistics = true )
+@ServiceRegistry( settings = {
+		@Setting( name = AvailableSettings.USE_QUERY_CACHE, value = "true" ),
+		@Setting( name = AvailableSettings.USE_SECOND_LEVEL_CACHE, value = "true" )
+} )
+@Jira( "https://hibernate.atlassian.net/browse/HHH-18439" )
+public class QueryCacheNullValueTest {
+	@Test
+	public void testNullProperty(SessionFactoryScope scope) {
+		executeQuery( scope, "select data from BasicEntity" );
+	}
+
+	@Test
+	public void testNullLiteral(SessionFactoryScope scope) {
+		executeQuery( scope, "select null from BasicEntity" );
+	}
+
+	private static void executeQuery(SessionFactoryScope scope, String hql) {
+		scope.getSessionFactory().getCache().evictQueryRegions();
+		final StatisticsImplementor statistics = scope.getSessionFactory().getStatistics();
+		statistics.clear();
+
+		for ( int i = 0; i < 2; i++ ) {
+			final int hitCount = i;
+			scope.inTransaction( session -> {
+				assertThat( session.createQuery( hql, String.class )
+									.setCacheable( true )
+									.getSingleResult() ).isNull();
+				// 0 hits, 1 miss, 1 put
+				assertThat( statistics.getQueryCacheHitCount() ).isEqualTo( hitCount );
+				assertThat( statistics.getQueryCacheMissCount() ).isEqualTo( 1 );
+				assertThat( statistics.getQueryCachePutCount() ).isEqualTo( 1 );
+				session.clear();
+			} );
+		}
+	}
+
+	@BeforeAll
+	public void setUp(SessionFactoryScope scope) {
+		scope.inTransaction( session -> session.persist( new BasicEntity( 1, null ) ) );
+	}
+
+	@AfterAll
+	public void tearDown(SessionFactoryScope scope) {
+		scope.getSessionFactory().getSchemaManager().truncateMappedObjects();
+	}
+}