src/web/src/tests/lib/dateFormat.test.ts

@@ -0,0 +1,111 @@
+import { describe, it, expect, afterEach, vi } from 'vitest';
+import {
+    AR_TZ,
+    formatInstant,
+    formatCivilDate,
+    formatCivilDateRange,
+    todayArgentina,
+    parseCivilDate,
+} from '@/lib/dateFormat';
+
+describe('dateFormat.ts', () => {
+    describe('AR_TZ constant', () => {
+        it('is America/Argentina/Buenos_Aires', () => {
+            expect(AR_TZ).toBe('America/Argentina/Buenos_Aires');
+        });
+    });
+
+    describe('formatInstant (Cat1 — UTC → AR display)', () => {
+        it('converts 01:30 UTC to 22:30 ART previous day', () => {
+            const iso = '2026-05-01T01:30:00.000Z';
+            const result = formatInstant(iso);
+            // format es-AR short + medium: "30/4/2026, 22:30:00" o similar
+            expect(result).toMatch(/30\/0?4\/2026/);
+            expect(result).toMatch(/22:30/);
+        });
+
+        it('uses AR timezone regardless of browser TZ', () => {
+            const iso = '2026-05-01T12:00:00.000Z'; // 09:00 ART
+            const result = formatInstant(iso);
+            expect(result).toMatch(/01\/0?5\/2026/);
+            expect(result).toMatch(/09:00/);
+        });
+    });
+
+    describe('formatCivilDate (Cat2 — yyyy-MM-dd → dd/MM/yyyy)', () => {
+        it('splits manually without new Date()', () => {
+            expect(formatCivilDate('2026-05-01')).toBe('01/05/2026');
+        });
+
+        it('preserves day for early-year dates', () => {
+            expect(formatCivilDate('2026-01-01')).toBe('01/01/2026');
+        });
+
+        it('preserves day for end-of-year dates', () => {
+            expect(formatCivilDate('2026-12-31')).toBe('31/12/2026');
+        });
+    });
+
+    describe('formatCivilDateRange', () => {
+        it('renders full range with arrow', () => {
+            expect(formatCivilDateRange('2026-05-01', '2026-12-31'))
+                .toBe('01/05/2026 → 31/12/2026');
+        });
+
+        it('renders open range when hasta is null', () => {
+            expect(formatCivilDateRange('2026-05-01', null))
+                .toBe('desde 01/05/2026');
+        });
+    });
+
+    describe('todayArgentina (fix BUG-FE-03)', () => {
+        afterEach(() => {
+            vi.useRealTimers();
+        });
+
+        it('returns 2026-04-30 at 22:30 ART of 30/04 (BUG-FE-03 regression)', () => {
+            // 22:30 ART = 01:30 UTC del día siguiente
+            vi.useFakeTimers();
+            vi.setSystemTime(new Date('2026-05-01T01:30:00.000Z'));
+
+            expect(todayArgentina()).toBe('2026-04-30');
+        });
+
+        it('returns 2026-05-01 at 00:30 ART of 01/05', () => {
+            // 00:30 ART = 03:30 UTC
+            vi.useFakeTimers();
+            vi.setSystemTime(new Date('2026-05-01T03:30:00.000Z'));
+
+            expect(todayArgentina()).toBe('2026-05-01');
+        });
+
+        it('returns 2024-02-28 at 22:30 ART of 28/02/2024 (bisiesto)', () => {
+            // 22:30 ART del 28/02/2024 = 01:30 UTC del 29/02/2024
+            vi.useFakeTimers();
+            vi.setSystemTime(new Date('2024-02-29T01:30:00.000Z'));
+
+            expect(todayArgentina()).toBe('2024-02-28');
+        });
+
+        it('returns 2026-12-31 at 22:30 ART of 31/12 (end of year)', () => {
+            // 22:30 ART del 31/12/2026 = 01:30 UTC del 01/01/2027
+            vi.useFakeTimers();
+            vi.setSystemTime(new Date('2027-01-01T01:30:00.000Z'));
+
+            expect(todayArgentina()).toBe('2026-12-31');
+        });
+    });
+
+    describe('parseCivilDate', () => {
+        it('splits "2026-05-01" into {year, month, day}', () => {
+            expect(parseCivilDate('2026-05-01')).toEqual({ year: 2026, month: 5, day: 1 });
+        });
+
+        it('does not use new Date() (no UTC creep)', () => {
+            const result = parseCivilDate('2026-01-01');
+            expect(result.year).toBe(2026);
+            expect(result.month).toBe(1);
+            expect(result.day).toBe(1);
+        });
+    });
+});