feat: add tests for normalizeName and RecipesService methods, including unit conversion and alias normalization

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

@@ -0,0 +1,95 @@
+import { RecipesService } from './recipes.service';
+
+// 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);
+
+describe('RecipesService.normalizeUnit', () => {
+  it('normaliserar aliaser', () => {
+    expect(normalize('tesked')).toBe('tsk');
+    expect(normalize('matsked')).toBe('msk');
+    expect(normalize('gram')).toBe('g');
+    expect(normalize('kilogram')).toBe('kg');
+    expect(normalize('deciliter')).toBe('dl');
+    expect(normalize('milliliter')).toBe('ml');
+  });
+
+  it('hanterar gemener och blanksteg', () => {
+    expect(normalize('  MSK  ')).toBe('msk');
+    expect(normalize('G')).toBe('g');
+  });
+
+  it('returnerar okänd enhet oförändrad', () => {
+    expect(normalize('kopp')).toBe('kopp');
+  });
+});
+
+describe('RecipesService.convertUnit', () => {
+  describe('viktkonvertering', () => {
+    it('konverterar g → kg', () => {
+      expect(convert(500, 'g', 'kg')).toBeCloseTo(0.5);
+    });
+
+    it('konverterar kg → g', () => {
+      expect(convert(1.5, 'kg', 'g')).toBeCloseTo(1500);
+    });
+
+    it('returnerar samma värde för identiska enheter', () => {
+      expect(convert(200, 'g', 'g')).toBe(200);
+    });
+  });
+
+  describe('volymkonvertering', () => {
+    it('konverterar dl → ml', () => {
+      expect(convert(2, 'dl', 'ml')).toBeCloseTo(200);
+    });
+
+    it('konverterar ml → dl', () => {
+      expect(convert(150, 'ml', 'dl')).toBeCloseTo(1.5);
+    });
+  });
+
+  describe('portionskonvertering', () => {
+    it('konverterar msk → tsk (1 msk ≈ 3 tsk)', () => {
+      expect(convert(2, 'msk', 'tsk')).toBeCloseTo(6);
+    });
+
+    it('konverterar tsk → msk', () => {
+      expect(convert(3, 'tsk', 'msk')).toBeCloseTo(1);
+    });
+  });
+
+  describe('normaliserar aliaser vid konvertering', () => {
+    it('konverterar "gram" → "kg"', () => {
+      expect(convert(1000, 'gram', 'kg')).toBeCloseTo(1);
+    });
+
+    it('konverterar "matsked" → "tsk"', () => {
+      expect(convert(1, 'matsked', 'tsk')).toBeCloseTo(3);
+    });
+  });
+
+  describe('felhantering', () => {
+    it('kastar fel för inkompatibla enhetstyper', () => {
+      expect(() => convert(100, 'g', 'dl')).toThrow();
+    });
+
+    it('kastar fel för noll-kvantitet', () => {
+      expect(() => convert(0, 'g', 'kg')).toThrow();
+    });
+
+    it('kastar fel för negativ kvantitet', () => {
+      expect(() => convert(-1, 'g', 'kg')).toThrow();
+    });
+
+    it('kastar fel för tom from-enhet', () => {
+      expect(() => convert(100, '', 'kg')).toThrow();
+    });
+
+    it('kastar fel för okänd enhet', () => {
+      expect(() => convert(100, 'kopp', 'dl')).toThrow();
+    });
+  });
+});