Add some new DateTime helpers

Author: engineering87

SharpHelpers/SharpHelpers.UnitTest/DateAndTime/DateTimeTest.cs

@@ -0,0 +1,78 @@
+// (c) 2023 SharpCoding
+// This code is licensed under MIT license (see LICENSE.txt for details)
+
+using System;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+using SharpCoding.SharpHelpers;
+using System.Linq;
+
+namespace SharpHelpers.UnitTest.DateAndTime
+{
+    [TestClass]
+    public class DateTimeTest
+    {
+        [TestMethod]
+        public void TestDateTimeSmart()
+        {
+            var dtDictionary = new System.Collections.Generic.Dictionary<string, string>()
+                    {
+                        {"M/dd/yyyy hh:mm", "10/11/2023 09:00"},
+                        {"MM/dd/yyyy hh:mm:ss tt zzz", "05/01/2009 01:30:42 PM -05:00"},
+                        {"g", "10/11/2023 09:00"}
+                    };
+
+            DateTimeSmart.AddFormats(dtDictionary.Keys.ToArray());
+
+            foreach (var key in dtDictionary.Keys)
+            {
+                DateTime dt = (DateTimeSmart)dtDictionary[key];
+                Assert.IsFalse(dt == DateTime.MinValue);
+            }
+
+            DateTime dt1 = (DateTimeSmart)"01-05-2023 22:30:55";
+            Assert.IsTrue(dt1 == new DateTime( 2023, 5, 1, 22, 30, 55, DateTimeKind.Local));
+        }
+
+        [TestMethod]
+        public void IsLeapYear_ShouldReturnTrueForLeapYear()
+        {
+            var leapYear = new DateTime(2024, 1, 1);
+            var isLeapYear = leapYear.IsLeapYear();
+
+            Assert.IsTrue(isLeapYear);
+        }
+
+        [TestMethod]
+        public void Age_ShouldCalculateCorrectAge()
+        {
+            var birthDate = new DateTime(1990, 8, 18);
+            var today = new DateTime(2024, 8, 18);
+            var expectedAge = 34;
+
+            var age = birthDate.Age();
+
+            Assert.AreEqual(expectedAge, age);
+        }
+
+        [TestMethod]
+        public void AddBusinessDays_ShouldSkipWeekends()
+        {
+            var startDate = new DateTime(2024, 8, 16); // Friday
+            var expected = new DateTime(2024, 8, 20); // 2 business days later (Tuesday)
+
+            var result = startDate.AddBusinessDays(2);
+
+            Assert.AreEqual(expected, result);
+        }
+
+        [TestMethod]
+        public void IsWeekend_ShouldReturnFalseForWeekday()
+        {
+            var monday = new DateTime(2024, 8, 19);
+
+            var isMondayWeekend = monday.IsWeekend();
+
+            Assert.IsFalse(isMondayWeekend);
+        }
+    }
+}

SharpHelpers/SharpHelpers/DateTimeHelper.cs

@@ -97,5 +97,63 @@ public static bool IsBetween(this DateTime dt, DateTime rangeBeg, DateTime range
         {
             return dt.Ticks >= rangeBeg.Ticks && dt.Ticks <= rangeEnd.Ticks;
         }
+
+        /// <summary>
+        /// Check if a day is a weekend.
+        /// </summary>
+        /// <param name="dateTime"></param>
+        /// <returns></returns>
+        public static bool IsWeekend(this DateTime dateTime)
+        {
+            return dateTime.DayOfWeek == DayOfWeek.Saturday || dateTime.DayOfWeek == DayOfWeek.Sunday;
+        }
+
+        /// <summary>
+        /// Add business days to a DateTime.
+        /// </summary>
+        /// <param name="dateTime"></param>
+        /// <param name="businessDays"></param>
+        /// <returns></returns>
+        public static DateTime AddBusinessDays(this DateTime dateTime, int businessDays)
+        {
+            if (businessDays == 0)
+                return dateTime;
+
+            int direction = businessDays > 0 ? 1 : -1;
+            int daysToAdd = Math.Abs(businessDays);
+
+            while (daysToAdd > 0)
+            {
+                dateTime = dateTime.AddDays(direction);
+                if (!dateTime.IsWeekend())
+                    daysToAdd--;
+            }
+
+            return dateTime;
+        }
+
+        /// <summary>
+        /// Return the age of a person.
+        /// </summary>
+        /// <param name="birthDate"></param>
+        /// <returns></returns>
+        public static int Age(this DateTime birthDate)
+        {
+            var today = DateTime.Today;
+            var age = today.Year - birthDate.Year;
+            if (birthDate.Date > today.AddYears(-age)) age--;
+            return age;
+        }
+
+        /// <summary>
+        /// Check if the year is a leap year.
+        /// </summary>
+        /// <param name="dateTime"></param>
+        /// <returns></returns>
+        public static bool IsLeapYear(this DateTime dateTime)
+        {
+            int year = dateTime.Year;
+            return DateTime.IsLeapYear(year);
+        }
     }
-}
+}