feat: add persistance to language selection

src/app/components/contact-form/contact-form.spec.ts

@@ -1,22 +1,24 @@
 import { ComponentFixture, TestBed } from '@angular/core/testing';
 
 import { ContactForm } from './contact-form';
-import { STRINGS_INJECTOR } from '../../app.config';
 import { strings } from '../../strings';
 import { By } from '@angular/platform-browser';
 import { ContactDTO } from '../../models/ContactDTO';
+import { LanguageManager } from '../../services/language-manager';
 
 describe('ContactForm', () => {
   let component: ContactForm;
   let fixture: ComponentFixture<ContactForm>;
+  let languageManager: jasmine.SpyObj<LanguageManager>;
 
   beforeEach(async () => {
+    languageManager = jasmine.createSpyObj(LanguageManager.name, [], { strings: strings.en });
+
     await TestBed.configureTestingModule({
       imports: [ContactForm],
-      providers: [{ provide: STRINGS_INJECTOR, useValue: strings }],
+      providers: [{ provide: LanguageManager, useValue: languageManager }],
     }).compileComponents();
 
-    TestBed.inject(STRINGS_INJECTOR);
     fixture = TestBed.createComponent(ContactForm);
     component = fixture.componentInstance;
     fixture.detectChanges();