diff --git a/dataformat-aasx/src/test/java/org/eclipse/digitaltwin/aas4j/v3/dataformat/aasx/serialization/AASXSerializerTest.java b/dataformat-aasx/src/test/java/org/eclipse/digitaltwin/aas4j/v3/dataformat/aasx/serialization/AASXSerializerTest.java
index 44328137..f2dcdf45 100644
--- a/dataformat-aasx/src/test/java/org/eclipse/digitaltwin/aas4j/v3/dataformat/aasx/serialization/AASXSerializerTest.java
+++ b/dataformat-aasx/src/test/java/org/eclipse/digitaltwin/aas4j/v3/dataformat/aasx/serialization/AASXSerializerTest.java
@@ -48,9 +48,11 @@ public class AASXSerializerTest {
     public void setup() throws IOException {
         byte[] operationManualContent = { 0, 1, 2, 3, 4 };
         byte[] thumbnail = { 0, 1, 2, 3, 4 };
-        InMemoryFile file = new InMemoryFile(operationManualContent, "file:///aasx/OperatingManual.pdf");
+        InMemoryFile file = new InMemoryFile(operationManualContent, "file:///TestFile.pdf");
+        InMemoryFile file2 = new InMemoryFile(operationManualContent, "file:///TestFile2.pdf");
         InMemoryFile inMemoryFileThumbnail = new InMemoryFile(thumbnail, "file:///master/verwaltungsschale-detail-part1.png");
         fileList.add(file);
+        fileList.add(file2);
         fileList.add(inMemoryFileThumbnail);
     }
 
diff --git a/dataformat-core/src/test/java/org/eclipse/digitaltwin/aas4j/v3/dataformat/core/AASFull.java b/dataformat-core/src/test/java/org/eclipse/digitaltwin/aas4j/v3/dataformat/core/AASFull.java
index b0cd0ae9..04b2f5e8 100644
--- a/dataformat-core/src/test/java/org/eclipse/digitaltwin/aas4j/v3/dataformat/core/AASFull.java
+++ b/dataformat-core/src/test/java/org/eclipse/digitaltwin/aas4j/v3/dataformat/core/AASFull.java
@@ -87,6 +87,8 @@ public class AASFull {
     public final static ConceptDescription CONCEPT_DESCRIPTION_4 = createConceptDescription4();
     public static final Environment ENVIRONMENT = createEnvironment();
     public static final String AAS_3_0_RC_02_DATA_SPECIFICATION_IEC_61360 = "https://admin-shell.io/aas/3/0/RC02/DataSpecificationIec61360";
+    private static final String FILE_MASTER_VERWALTUNGSSCHALE_DETAIL_PART1_PNG = "file:///master/verwaltungsschale-detail-part1.png";
+    private static final String IMAGE_PNG = "image/png";
 
     public static AssetAdministrationShell createAAS1() {
         return new DefaultAssetAdministrationShell.Builder()
@@ -116,6 +118,10 @@ public static AssetAdministrationShell createAAS1() {
                         //                .value("http://acplt.org/Submodels/Assets/TestAsset/BillOfMaterial")
                         //                .build()))
                         //        .build())
+                        .defaultThumbnail(new DefaultResource.Builder()
+                                .contentType(IMAGE_PNG)
+                                .path(FILE_MASTER_VERWALTUNGSSCHALE_DETAIL_PART1_PNG)
+                                .build())
                         .build())
                 .submodels(new DefaultReference.Builder()
                         .keys(new DefaultKey.Builder()
@@ -1326,7 +1332,7 @@ public static Submodel createSubmodel6() {
                                                 .build())
                                         .type(ReferenceTypes.EXTERNAL_REFERENCE)
                                         .build())
-                                .value("file:///TestFile.pdf")
+                                .value("file:///TestFile2.pdf")
                                 .contentType("application/pdf")
                                 .build())
                         .value(new DefaultReferenceElement.Builder()