Initial commit

frontend/tests/unit/utils/formatting.test.ts

@@ -0,0 +1,59 @@
+import { describe, it, expect } from 'vitest'
+import { formatDayCount, formatPercentage } from '@/utils/formatting'
+
+describe('formatting.ts utilities', () => {
+  describe('formatDayCount', () => {
+    it('returns singular form for 1 day', () => {
+      expect(formatDayCount(1)).toBe('1 dag')
+    })
+
+    it('returns plural form for 0 days', () => {
+      expect(formatDayCount(0)).toBe('0 dagar')
+    })
+
+    it('returns plural form for 2 days', () => {
+      expect(formatDayCount(2)).toBe('2 dagar')
+    })
+
+    it('returns plural form for many days', () => {
+      expect(formatDayCount(25)).toBe('25 dagar')
+      expect(formatDayCount(365)).toBe('365 dagar')
+    })
+
+    it('handles large numbers', () => {
+      expect(formatDayCount(1000)).toBe('1000 dagar')
+    })
+  })
+
+  describe('formatPercentage', () => {
+    it('formats simple percentage', () => {
+      expect(formatPercentage(1, 4)).toBe('25%')
+    })
+
+    it('rounds to nearest integer', () => {
+      expect(formatPercentage(1, 3)).toBe('33%') // 33.333...%
+      expect(formatPercentage(2, 3)).toBe('67%') // 66.666...%
+    })
+
+    it('handles 0% correctly', () => {
+      expect(formatPercentage(0, 10)).toBe('0%')
+    })
+
+    it('handles 100% correctly', () => {
+      expect(formatPercentage(10, 10)).toBe('100%')
+    })
+
+    it('returns 0% when denominator is 0', () => {
+      expect(formatPercentage(5, 0)).toBe('0%')
+    })
+
+    it('handles fractional results with proper rounding', () => {
+      expect(formatPercentage(1, 2)).toBe('50%')
+      expect(formatPercentage(3, 4)).toBe('75%')
+    })
+
+    it('works with large numbers', () => {
+      expect(formatPercentage(500, 1000)).toBe('50%')
+    })
+  })
+})