diff --git a/src/app/native-library-wrapper.service.spec.ts b/src/app/native-library-wrapper.service.spec.ts
index 35f2936..4f50438 100644
--- a/src/app/native-library-wrapper.service.spec.ts
+++ b/src/app/native-library-wrapper.service.spec.ts
@@ -1,6 +1,6 @@
-import { TestBed, inject } from '@angular/core/testing';
+import {inject, TestBed} from '@angular/core/testing';
 
-import { NativeLibraryWrapperService } from './native-library-wrapper.service';
+import {NativeLibraryWrapperService} from './native-library-wrapper.service';
 
 describe('NativeLibraryWrapperService', () => {
   beforeEach(() => {
@@ -12,4 +12,22 @@ describe('NativeLibraryWrapperService', () => {
   it('should be created', inject([NativeLibraryWrapperService], (service: NativeLibraryWrapperService) => {
     expect(service).toBeTruthy();
   }));
+
+  it('should convert punycode', inject([NativeLibraryWrapperService], (service: NativeLibraryWrapperService) => {
+    expect(service.punycode).toBeTruthy();
+    expect(service.punycode.encode('bärneruhr')).toEqual('brneruhr-0za');
+    expect(service.punycode.decode('brneruhr-0za')).toEqual('bärneruhr');
+  }));
+
+  it('should convert utf8', inject([NativeLibraryWrapperService], (service: NativeLibraryWrapperService) => {
+    expect(service.utf8).toBeTruthy();
+    expect(service.utf8.encode('bärneruhr')).toEqual('bärneruhr');
+    expect(service.utf8.decode('bärneruhr')).toEqual('bärneruhr');
+  }));
+
+  it('should convert quoted printable', inject([NativeLibraryWrapperService], (service: NativeLibraryWrapperService) => {
+    expect(service.quotedPrintable).toBeTruthy();
+    expect(service.quotedPrintable.encode('bärneruhr')).toEqual('b=E4rneruhr');
+    expect(service.quotedPrintable.decode('b=E4rneruhr')).toEqual('bärneruhr');
+  }));
 });