HHH-19322 Test case for batched unidirectional one-to-many update

hibernate-core/src/test/java/org/hibernate/orm/test/collection/OneToManyUnidirectionalBatchingTest.java

@@ -0,0 +1,88 @@
+package org.hibernate.orm.test.collection;
+
+import jakarta.persistence.*;
+import org.hibernate.cfg.AvailableSettings;
+import org.hibernate.testing.orm.junit.*;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import java.util.concurrent.atomic.AtomicReference;
+
+@DomainModel(annotatedClasses = {
+        OneToManyUnidirectionalBatchingTest.Person.class,
+        OneToManyUnidirectionalBatchingTest.Phone.class,
+})
+@SessionFactory
+@ServiceRegistry(
+        settings = {
+                @Setting(name = AvailableSettings.STATEMENT_BATCH_SIZE, value = "50"),
+        }
+)
+@JiraKey(value = "HHH-19322")
+public class OneToManyUnidirectionalBatchingTest {
+
+    private final AtomicReference<Long> person1Id = new AtomicReference<>();
+    private final AtomicReference<Long> person2Id = new AtomicReference<>();
+    private final AtomicReference<Long> phoneId = new AtomicReference<>();
+
+    @BeforeAll
+    public void prepare(SessionFactoryScope scope) {
+        scope.inTransaction(session -> {
+            Phone phone = new Phone();
+            Phone dontCare = new Phone();
+            session.persist(phone);
+            phoneId.set(phone.id);
+            session.persist(dontCare);
+
+            Person person1 = new Person();
+            Person person2 = new Person();
+            session.persist(person1);
+            person1Id.set(person1.id);
+            session.persist(person2);
+            person2Id.set(person2.id);
+
+            person1.getPhones().addAll(Arrays.asList(phone, dontCare));
+        });
+    }
+
+    @Test
+    public void testBatching(SessionFactoryScope scope) {
+        scope.inTransaction(session -> {
+            // load person2 first, such that changes to its phones collection are flushed before person1's
+            Person person2 = session.find(Person.class, person2Id.get());
+            Person person1 = session.find(Person.class, person1Id.get());
+            Phone phone = session.find(Phone.class, phoneId.get());
+
+            person1.getPhones().remove(phone);
+            person2.getPhones().add(phone);
+        });
+    }
+
+    @Entity(name = "Person")
+    public static class Person {
+
+        @Id
+        @GeneratedValue
+        private Long id;
+
+        @JoinColumn(name = "person_id")
+        @OneToMany
+        private List<Phone> phones = new ArrayList<>();
+
+        public List<Phone> getPhones() {
+            return phones;
+        }
+    }
+
+    @Entity(name = "Phone")
+    public static class Phone {
+
+        @Id
+        @GeneratedValue
+        private Long id;
+    }
+
+}