Adding unit tests for isToday, isTomorrow and isYesterday

src/libs/DateUtils.js

@@ -384,6 +384,9 @@ const DateUtils = {
     subtractMillisecondsFromDateTime,
     getDateStringFromISOTimestamp,
     getStatusUntilDate,
+    isToday,
+    isTomorrow,
+    isYesterday,
 };
 
 export default DateUtils;

tests/unit/DateUtilsTest.js

@@ -1,5 +1,5 @@
 import Onyx from 'react-native-onyx';
-import {format as tzFormat} from 'date-fns-tz';
+import {format as tzFormat, utcToZonedTime} from 'date-fns-tz';
 import {addMinutes, subHours, subMinutes, subSeconds, format, setMinutes, setHours, subDays, addDays} from 'date-fns';
 import CONST from '../../src/CONST';
 import DateUtils from '../../src/libs/DateUtils';
@@ -130,6 +130,34 @@ describe('DateUtils', () => {
         expect(result).toBe(expectedDateTime);
     });
 
+    describe('Date Comparison Functions', () => {
+        const today = new Date();
+        const tomorrow = addDays(today, 1);
+        const yesterday = subDays(today, 1);
+
+        const todayInTimezone = utcToZonedTime(today, timezone);
+        const tomorrowInTimezone = utcToZonedTime(tomorrow, timezone);
+        const yesterdayInTimezone = utcToZonedTime(yesterday, timezone);
+
+        it('isToday should correctly identify today', () => {
+            expect(DateUtils.isToday(todayInTimezone, timezone)).toBe(true);
+            expect(DateUtils.isToday(tomorrowInTimezone, timezone)).toBe(false);
+            expect(DateUtils.isToday(yesterdayInTimezone, timezone)).toBe(false);
+        });
+
+        it('isTomorrow should correctly identify tomorrow', () => {
+            expect(DateUtils.isTomorrow(tomorrowInTimezone, timezone)).toBe(true);
+            expect(DateUtils.isTomorrow(todayInTimezone, timezone)).toBe(false);
+            expect(DateUtils.isTomorrow(yesterdayInTimezone, timezone)).toBe(false);
+        });
+
+        it('isYesterday should correctly identify yesterday', () => {
+            expect(DateUtils.isYesterday(yesterdayInTimezone, timezone)).toBe(true);
+            expect(DateUtils.isYesterday(todayInTimezone, timezone)).toBe(false);
+            expect(DateUtils.isYesterday(tomorrowInTimezone, timezone)).toBe(false);
+        });
+    });
+
     describe('getDBTime', () => {
         it('should return the date in the format expected by the database', () => {
             const getDBTime = DateUtils.getDBTime();