Added DateTime extension tests

Author: arbitrarybytes

src/ArbitraryExtensions.Tests/DateTimeExtensionsTests.cs

@@ -7,13 +7,23 @@ namespace ArbitraryExtensions.Tests
     [TestFixture]
     public class DateTimeExtensionsTests
     {
-        static readonly DateTime today = DateTime.Now;
-
         [Test]
         public void TestIsInRange()
         {
-            var daysAgo = DateTime.Now.AddDays(-10);
-            //Assert.IsTrue(DateTime.Now.AddDays(-5).IsInRange(today, daysAgo));
+            var start = new DateTime(2020, 1, 1);
+            var end = new DateTime(2020, 2, 1);
+            var inRange = new DateTime(2020, 1, 5);
+
+            Assert.IsTrue(inRange.IsInRange(start, end));
+        }
+
+        [Test]
+        public void TestElapsed()
+        {
+            var start = new DateTime(2020, 1, 1);
+            var end = new DateTime(2020, 2, 1);
+
+            Assert.AreEqual((end - start), start.Elapsed(end));
         }
     }
 }

src/ArbitraryExtensions/Core/DateTimeExtensions.cs

@@ -5,8 +5,9 @@ public static class DateTimeExtensions
     {
         /// <summary>Gets the elapsed timespan between the provided value and DateTime.Now</summary>
         /// <param name="value">the start datetime value</param>
+        /// <param name="endDate">the end datetime</param>
         /// <returns>elapsed timespan instance</returns>
-        public static TimeSpan Elapsed(this DateTime value) => DateTime.Now.Subtract(value);
+        public static TimeSpan Elapsed(this DateTime value, DateTime endDate) => endDate.Subtract(value);
 
         /// <summary>Gets if the input date is between the provided start and end date</summary>
         /// <param name="currentDate">the input date</param>