HHH-1914 - test case for UnsupportedOperationException upon merge of unmodifiable collection

Signed-off-by: Jan Schatteman <jschatte@redhat.com>

hibernate-core/src/test/java/org/hibernate/orm/test/annotations/manytomany/UnmodifiableCollectionMergeTest.java

@@ -0,0 +1,66 @@
+/*
+ * SPDX-License-Identifier: LGPL-2.1-or-later
+ * Copyright Red Hat Inc. and Hibernate Authors
+ */
+package org.hibernate.orm.test.annotations.manytomany;
+
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.Set;
+
+import org.hibernate.dialect.H2Dialect;
+import org.hibernate.testing.orm.junit.FailureExpected;
+import org.hibernate.testing.orm.junit.RequiresDialect;
+import org.hibernate.testing.orm.junit.DomainModel;
+import org.hibernate.testing.orm.junit.SessionFactory;
+import org.hibernate.testing.orm.junit.SessionFactoryScope;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * @author Jan Schatteman
+ */
+@RequiresDialect( value = H2Dialect.class )
+@FailureExpected( jiraKey = "HHH-1914", reason = "throws an UnsupportedOperationException")
+@DomainModel(
+		annotatedClasses = {
+				Cat.class, Woman.class, Man.class
+		}
+)
+@SessionFactory
+public class UnmodifiableCollectionMergeTest {
+
+	@Test
+	public void testMergeUnmodifiableCollection(SessionFactoryScope scope) {
+		scope.inTransaction(
+				session -> {
+					CatPk catPk = new CatPk();
+					catPk.setName( "Minou" );
+					catPk.setThoroughbred( "Persian" );
+					Cat cat = new Cat();
+					cat.setId( catPk );
+
+					WomanPk womanPk = new WomanPk();
+					womanPk.setFirstName( "Emma" );
+					womanPk.setLastName( "Peel" );
+					Woman woman = new Woman();
+					woman.setId( womanPk );
+
+					Set<Woman> women = new HashSet<>();
+					women.add( woman );
+
+					cat.setHumanContacts( Collections.unmodifiableSet( women ) );
+					Set<Cat> cats = new HashSet<>();
+					cats.add( cat );
+					woman.setCats( Collections.unmodifiableSet(cats) );
+
+					session.persist( cat );
+					session.persist( woman );
+
+					session.flush();
+					session.merge( woman );
+				}
+		);
+	}
+
+}