diff --git a/packages/monaco-editor-wrapper/test/editorAppExtended.test.ts b/packages/monaco-editor-wrapper/test/editorAppExtended.test.ts
index 251191c..60466c6 100644
--- a/packages/monaco-editor-wrapper/test/editorAppExtended.test.ts
+++ b/packages/monaco-editor-wrapper/test/editorAppExtended.test.ts
@@ -1,22 +1,7 @@
 import { describe, expect, test } from 'vitest';
-import { EditorAppConfigExtended, EditorAppExtended, UserConfig, verifyUrlorCreateDataUrl } from 'monaco-editor-wrapper';
+import { EditorAppConfigExtended, EditorAppExtended, verifyUrlorCreateDataUrl } from 'monaco-editor-wrapper';
 import { createBaseConfig, createEditorAppConfig } from './helper.js';
 
-/**
- * WA: Create an instance for testing that does not specify any additional services.
- *
- * Prevents:
- * Error: Unable to load extension-file://vscode.theme-defaults/themes/light_modern.json:
- * Unable to read file 'extension-file://vscode.theme-defaults/themes/light_modern.json' (TypeError: Failed to fetch)
- */
-const createExtendedApp = (name: string, userConfig: UserConfig) => {
-    const app = new EditorAppExtended(name, userConfig);
-    app.specifyServices = () => {
-        return {};
-    };
-    return app;
-};
-
 describe('Test EditorAppExtended', () => {
 
     test('verifyUrlorCreateDataUrl: url', () => {
@@ -36,14 +21,14 @@ describe('Test EditorAppExtended', () => {
         appConfig.userConfiguration = {
             json: '{ "editor.semanticHighlighting.enabled": true }'
         };
-        const app = createExtendedApp('config defaults', config);
+        const app = new EditorAppExtended('config defaults', config);
         expect(app.getConfig().userConfiguration?.json).toEqual('{ "editor.semanticHighlighting.enabled": true }');
     });
 
     test('isAppConfigDifferent: basic', () => {
         const orgConfig = createEditorAppConfig('extended') as EditorAppConfigExtended;
         const config = createEditorAppConfig('extended') as EditorAppConfigExtended;
-        const app = createExtendedApp('test', createBaseConfig('extended'));
+        const app = new EditorAppExtended('test', createBaseConfig('extended'));
         expect(app.isAppConfigDifferent(orgConfig, config, false)).toBeFalsy();
 
         config.code = 'test';
diff --git a/packages/monaco-editor-wrapper/test/helper.ts b/packages/monaco-editor-wrapper/test/helper.ts
index 765e661..8d24d3a 100644
--- a/packages/monaco-editor-wrapper/test/helper.ts
+++ b/packages/monaco-editor-wrapper/test/helper.ts
@@ -1,4 +1,4 @@
-import { UserConfig, EditorAppType } from 'monaco-editor-wrapper';
+import { UserConfig, EditorAppType, EditorAppExtended, MonacoEditorLanguageClientWrapper } from 'monaco-editor-wrapper';
 
 export const createMonacoEditorDiv = () => {
     const div = document.createElement('div');
@@ -26,3 +26,24 @@ export const createEditorAppConfig = (type: EditorAppType) => {
         useDiffEditor: false,
     };
 };
+
+export const updateExtendedAppPrototyp = () => {
+    EditorAppExtended.prototype.specifyServices = () => {
+        console.log('Using overriden EditorAppExtended.prototype.specifyServices');
+        return {};
+    };
+};
+
+/**
+ * WA: Create an instance for testing that does not specify any additional services.
+ *
+ * Prevents:
+ * Error: Unable to load extension-file://vscode.theme-defaults/themes/light_modern.json:
+ * Unable to read file 'extension-file://vscode.theme-defaults/themes/light_modern.json' (TypeError: Failed to fetch)
+ */
+export const createWrapper = async (userConfig: UserConfig) => {
+    updateExtendedAppPrototyp();
+    const wrapper = new MonacoEditorLanguageClientWrapper();
+    await wrapper.init(userConfig);
+    return wrapper;
+};
diff --git a/packages/monaco-editor-wrapper/test/languageClientWrapper.test.ts b/packages/monaco-editor-wrapper/test/languageClientWrapper.test.ts
index 73b2520..13dbbfb 100644
--- a/packages/monaco-editor-wrapper/test/languageClientWrapper.test.ts
+++ b/packages/monaco-editor-wrapper/test/languageClientWrapper.test.ts
@@ -1,16 +1,10 @@
 import { describe, expect, test } from 'vitest';
-import { MonacoEditorLanguageClientWrapper } from 'monaco-editor-wrapper';
-import { createBaseConfig } from './helper.js';
-
-// if (!window.MonacoEnvironment) {
-//     window.MonacoEnvironment = {};
-// }
+import { createBaseConfig, createWrapper } from './helper.js';
 
 describe('Test LanguageClientWrapper', () => {
 
     test('Not Running after construction', async () => {
-        const wrapper = new MonacoEditorLanguageClientWrapper();
-        await wrapper.init(createBaseConfig('extended'));
+        const wrapper = await createWrapper(createBaseConfig('extended'));
 
         const languageClientWrapper = wrapper.getLanguageClientWrapper();
         expect(languageClientWrapper).toBeDefined();
@@ -21,8 +15,7 @@ describe('Test LanguageClientWrapper', () => {
     });
 
     test('Constructor: no config', async () => {
-        const wrapper = new MonacoEditorLanguageClientWrapper();
-        await wrapper.init(createBaseConfig('extended'));
+        const wrapper = await createWrapper(createBaseConfig('extended'));
 
         const languageClientWrapper = wrapper.getLanguageClientWrapper();
         expect(languageClientWrapper).toBeDefined();
@@ -53,7 +46,6 @@ describe('Test LanguageClientWrapper', () => {
         });
 
         // setup the wrapper
-        const wrapper = new MonacoEditorLanguageClientWrapper();
         const config = createBaseConfig('extended');
         config.languageClientConfig = {
             options: {
@@ -61,7 +53,7 @@ describe('Test LanguageClientWrapper', () => {
                 worker
             }
         };
-        await wrapper.init(config);
+        const wrapper = await createWrapper(config);
 
         const languageClientWrapper = wrapper.getLanguageClientWrapper();
         expect(languageClientWrapper).toBeDefined();
@@ -77,7 +69,6 @@ describe('Test LanguageClientWrapper', () => {
     });
 
     test('Constructor: config', async () => {
-        const wrapper = new MonacoEditorLanguageClientWrapper();
         const config = createBaseConfig('extended');
         config.languageClientConfig = {
             options: {
@@ -85,7 +76,7 @@ describe('Test LanguageClientWrapper', () => {
                 url: 'ws://localhost:12345/Tester'
             }
         };
-        await wrapper.init(config);
+        const wrapper = await createWrapper(config);
 
         const languageClientWrapper = wrapper.getLanguageClientWrapper();
         expect(languageClientWrapper).toBeDefined();
@@ -94,7 +85,6 @@ describe('Test LanguageClientWrapper', () => {
     });
 
     test('Start: unreachable url', async () => {
-        const wrapper = new MonacoEditorLanguageClientWrapper();
         const config = createBaseConfig('extended');
         config.languageClientConfig = {
             options: {
@@ -103,7 +93,7 @@ describe('Test LanguageClientWrapper', () => {
                 name: 'test-unreachable'
             }
         };
-        await wrapper.init(config);
+        const wrapper = await createWrapper(config);
 
         const languageClientWrapper = wrapper.getLanguageClientWrapper();
         expect(languageClientWrapper).toBeDefined();
@@ -127,7 +117,6 @@ describe('Test LanguageClientWrapper', () => {
     });
 
     test('Start: unreachable worker url', async () => {
-        const wrapper = new MonacoEditorLanguageClientWrapper();
         const config = createBaseConfig('extended');
         config.languageClientConfig = {
             options: {
@@ -136,7 +125,7 @@ describe('Test LanguageClientWrapper', () => {
                 type: 'classic'
             }
         };
-        await wrapper.init(config);
+        const wrapper = await createWrapper(config);
 
         const languageClientWrapper = wrapper.getLanguageClientWrapper();
         expect(languageClientWrapper).toBeDefined();
diff --git a/vite.config.ts b/vite.config.ts
index fdbb0ac..b5cabe4 100644
--- a/vite.config.ts
+++ b/vite.config.ts
@@ -68,8 +68,7 @@ export default defineConfig(() => {
             pool: 'threads',
             poolOptions: {
                 threads: {
-                    minThreads: 1,
-                    maxThreads: 1
+                    isolate: true
                 }
             },
             browser: {