diff --git a/projects/aas-server/src/test/packages/opcua/opcua-reader.spec.ts b/projects/aas-server/src/test/packages/opcua/opcua-reader.spec.ts
index 0b964b51..2ac33356 100644
--- a/projects/aas-server/src/test/packages/opcua/opcua-reader.spec.ts
+++ b/projects/aas-server/src/test/packages/opcua/opcua-reader.spec.ts
@@ -7,26 +7,26 @@
  *****************************************************************************/
 
 import { describe, beforeEach, it, expect, jest } from '@jest/globals';
+import { createSpyObj } from 'fhg-jest';
 import { Logger } from '../../../app/logging/logger.js';
 import { OpcuaReader } from '../../../app/packages/opcua/opcua-reader.js';
 import { OPCUAComponent } from '../../../app/packages/opcua/opcua.js';
 import { OpcuaDataTypeDictionary } from '../../../app/packages/opcua/opcua-data-type-dictionary.js';
-import { createSpyObj } from 'fhg-jest';
 
-describe('OpcuaReader', function () {
+describe('OpcuaReader', () => {
     let reader: OpcuaReader;
     let logger: jest.Mocked<Logger>;
     let origin: jest.Mocked<OPCUAComponent>;
     let dataTypes: jest.Mocked<OpcuaDataTypeDictionary>;
 
-    beforeEach(function () {
+    beforeEach(() => {
         logger = createSpyObj<Logger>(['error', 'warning', 'info', 'debug', 'start', 'stop']);
         origin = createSpyObj<OPCUAComponent>({}, ['displayName', 'hasProperty', 'nodeClass']);
         dataTypes = createSpyObj<OpcuaDataTypeDictionary>(['get']);
         reader = new OpcuaReader(logger, origin, dataTypes);
     });
 
-    it('should be created', function () {
+    it('should be created', () => {
         expect(reader).toBeTruthy();
     });
 });
diff --git a/projects/fhg-jest/src/lib/create-spy-obj.ts b/projects/fhg-jest/src/lib/create-spy-obj.ts
index b8c837f5..ae976fe3 100644
--- a/projects/fhg-jest/src/lib/create-spy-obj.ts
+++ b/projects/fhg-jest/src/lib/create-spy-obj.ts
@@ -28,7 +28,9 @@ export function createSpyObj<T extends object>(
 
     if (propertyNames) {
         if (Array.isArray(propertyNames)) {
-            throw new Error('Not implemented.');
+            for (const propertyName of propertyNames) {
+                obj[propertyName] = propertyNames[propertyName];
+            }
         } else {
             for (const propertyName in propertyNames) {
                 obj[propertyName] = propertyNames[propertyName];