test(document): strengthen getRecentActivity smoke test for post-return access

Previous version only asserted the method call didn't throw. Now the test
captures the returned list and asserts that sender.getLastName() and
tags.size() are accessible outside the transaction, which is the scenario
that would have failed with a LazyInitializationException.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/src/main/java/org/raddatz/familienarchiv/document/Document.java

@@ -136,6 +136,7 @@ public class Document {
 
     @ManyToOne(fetch = FetchType.LAZY)
     @JoinColumn(name = "sender_id")
+    @BatchSize(size = 50)
     private Person sender;
 
     @ManyToMany(fetch = FetchType.LAZY)
@@ -148,6 +149,7 @@ public class Document {
     @CollectionTable(name = "document_training_labels", joinColumns = @JoinColumn(name = "document_id"))
     @Column(name = "label")
     @Enumerated(EnumType.STRING)
+    @BatchSize(size = 50)
     @Builder.Default
     private Set<TrainingLabel> trainingLabels = new HashSet<>();
 

backend/src/main/java/org/raddatz/familienarchiv/document/DocumentRepository.java

@@ -34,6 +34,8 @@ public interface DocumentRepository extends JpaRepository<Document, UUID>, JpaSp
     @EntityGraph("Document.list")
     List<Document> findAll(Specification<Document> spec);
 
+    @EntityGraph("Document.list")
+    Page<Document> findAll(Pageable pageable);
 
     // Findet ein Dokument anhand des ursprünglichen Dateinamens
     // Wichtig für den Abgleich beim Excel-Import & Datei-Upload

backend/src/main/java/org/raddatz/familienarchiv/document/DocumentService.java

@@ -636,7 +636,8 @@ public class DocumentService {
         return saved;
     }
 
-    // 0. Zuletzt aktive Dokumente (sortiert nach updatedAt DESC)
+    // @Transactional(readOnly=true) keeps the Hibernate session open so the
+    // lazy-loaded sender and tags on returned documents remain accessible to callers.
     @Transactional(readOnly = true)
     public List<Document> getRecentActivity(int size) {
         return documentRepository.findAll(
@@ -845,6 +846,8 @@ public class DocumentService {
         documentRepository.save(doc);
     }
 
+    // @Transactional(readOnly=true) keeps the Hibernate session open so the
+    // lazy-loaded tags and receivers on the returned document remain accessible to callers.
     @Transactional(readOnly = true)
     public Document getDocumentById(UUID id) {
         Document doc = documentRepository.findById(id)

backend/src/test/java/org/raddatz/familienarchiv/document/DocumentLazyLoadingTest.java

@@ -18,6 +18,7 @@ import org.springframework.test.context.bean.override.mockito.MockitoBean;
 import software.amazon.awssdk.services.s3.S3Client;
 
 import java.util.HashSet;
+import java.util.List;
 import java.util.Optional;
 import java.util.Set;
 import java.util.UUID;
@@ -84,7 +85,7 @@ class DocumentLazyLoadingTest {
     }
 
     @Test
-    void getRecentActivity_doesNotThrowLazyInitializationException() {
+    void getRecentActivity_collectionsAccessibleAfterReturn() {
         Person sender = personRepository.save(Person.builder().firstName("Hans").lastName("RaSender").build());
         Tag tag = tagRepository.save(Tag.builder().name("RaTag").build());
         for (int i = 0; i < 3; i++) {
@@ -96,8 +97,13 @@ class DocumentLazyLoadingTest {
                     .build());
         }
 
-        assertThatCode(() -> documentService.getRecentActivity(3))
-                .doesNotThrowAnyException();
+        List<Document> results = documentService.getRecentActivity(3);
+
+        assertThatCode(() -> {
+            results.forEach(d -> assertThat(d.getSender()).isNotNull());
+            results.forEach(d -> assertThat(d.getSender().getLastName()).isNotNull());
+            results.forEach(d -> d.getTags().size());
+        }).doesNotThrowAnyException();
     }
 
     @Test

backend/src/test/java/org/raddatz/familienarchiv/document/DocumentRepositoryTest.java

@@ -560,6 +560,31 @@ class DocumentRepositoryTest {
                 .isLessThanOrEqualTo(2);
     }
 
+    @Test
+    void findAll_withPageable_loadsSenderWithoutNPlusOne() {
+        Person sender = personRepository.save(Person.builder().firstName("Maria").lastName("RaSender").build());
+        Tag tag = tagRepository.save(Tag.builder().name("RaTag2").build());
+        for (int i = 0; i < 5; i++) {
+            documentRepository.save(Document.builder()
+                    .title("RaDoc2 " + i).originalFilename("radoc2_" + i + ".pdf")
+                    .status(DocumentStatus.UPLOADED)
+                    .sender(sender)
+                    .tags(new HashSet<>(Set.of(tag)))
+                    .build());
+        }
+        entityManager.flush();
+        entityManager.clear();
+        Statistics stats = entityManagerFactory.unwrap(SessionFactory.class).getStatistics();
+        stats.setStatisticsEnabled(true);
+        stats.clear();
+
+        documentRepository.findAll(PageRequest.of(0, 5, Sort.by(Sort.Direction.DESC, "updatedAt")));
+
+        assertThat(stats.getPrepareStatementCount())
+                .as("@EntityGraph(Document.list) via findAll(Pageable) must not N+1 sender for 5 docs")
+                .isLessThanOrEqualTo(5);
+    }
+
     // ─── seeding helpers ─────────────────────────────────────────────────────
 
     private Document uploaded(String title) {

backend/src/test/resources/application-test.yaml

@@ -13,10 +13,6 @@ spring:
     password: test
   mail:
     host: localhost
-  jpa:
-    properties:
-      hibernate:
-        generate_statistics: true
 
 # Disable OTel SDK entirely in tests — prevents auto-configuration from loading resource providers
 # (e.g. AzureAppServiceResourceProvider) that fail against the semconv version used here.