refactor: simplify unit conversion tests by importing utility functions directly

backend/src/recipes/recipes.service.spec.ts

@@ -1,12 +1,9 @@
-import { RecipesService } from './recipes.service';
+import { normalizeUnit, convertUnit } from '../common/utils/units';
 
-// Vi instansierar utan Prisma eftersom vi bara testar privata hjälpmetoder
-const service = new (RecipesService as any)(null);
-const convert = (q: number, from: string, to: string) =>
-  (service as any).convertUnit(q, from, to, 'testprodukt');
-const normalize = (u: string) => (service as any).normalizeUnit(u);
+const convert = (q: number, from: string, to: string) => convertUnit(q, from, to);
+const normalize = (u: string) => normalizeUnit(u);
 
-describe('RecipesService.normalizeUnit', () => {
+describe('normalizeUnit', () => {
   it('normaliserar aliaser', () => {
     expect(normalize('tesked')).toBe('tsk');
     expect(normalize('matsked')).toBe('msk');
@@ -26,7 +23,7 @@ describe('RecipesService.normalizeUnit', () => {
   });
 });
 
-describe('RecipesService.convertUnit', () => {
+describe('convertUnit', () => {
   describe('viktkonvertering', () => {
     it('konverterar g → kg', () => {
       expect(convert(500, 'g', 'kg')).toBeCloseTo(0.5);