Add TakeLast extension

ShittyLINQ/TakeLast.cs

@@ -0,0 +1,29 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace ShittyLINQ
+{
+    public static partial class Extensions
+    {
+        public static IEnumerable<T> TakeLast<T>(this IEnumerable<T> self, int count)
+        {
+            if (self == null) throw new ArgumentNullException();
+
+            var numberElements = self.Count();
+
+            if (numberElements < count) throw new ArgumentOutOfRangeException();
+
+            var index = 0;
+
+            foreach (T item in self)
+            {
+                if(index >= numberElements - count)
+                {
+                    yield return item;
+                }
+                index++;
+            }
+        }
+    }
+}

ShittyLinqTests/TakeLastTests.cs

@@ -0,0 +1,53 @@
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+using ShittyLINQ;
+using System;
+using System.Collections.Generic;
+
+namespace ShittyTests
+{
+    [TestClass]
+    public class TakeLastTests
+    {
+        [TestMethod]
+        public void When_Count_Is_Greather_Than_Element_In_List_Then_Throw_OutOfRange_Exception()
+        {
+            var list = new List<int> { 1, 2, 3, 4 };
+
+            Assert.ThrowsException<ArgumentOutOfRangeException>(() => list.TakeLast(5).ToList());
+        }
+
+        [TestMethod]
+        public void When_List_Is_Null_Then_Throw_Exception()
+        {
+            IEnumerable<int> list = null;
+
+            Assert.ThrowsException<ArgumentNullException>(() => list.TakeLast(5).ToList());
+        }
+
+        [TestMethod]
+        public void When_Take_Last_Five_Elements_Then_Should_Return_List_Of_Five()
+        {
+            var list = new List<int> { 1, 2, 3, 4, 5, 6, 7 };
+            var expectedList = new List<int> { 3, 4, 5, 6, 7 };
+
+            var lastFiveElements = list.TakeLast(5).ToList();
+
+            Assert.IsTrue(lastFiveElements.Count == 5);
+            CollectionAssert.AreEqual(expectedList, lastFiveElements);
+
+        }
+
+        [TestMethod]
+        public void When_Take_Last_Five_Elements_In_List_Of_Five_Then_Should_Return_Same_List()
+        {
+            var list = new List<int> { 3, 4, 5, 6, 7 };
+            var expectedList = new List<int> { 3, 4, 5, 6, 7 };
+
+            var lastFiveElements = list.TakeLast(5).ToList();
+
+            Assert.IsTrue(lastFiveElements.Count == 5);
+            CollectionAssert.AreEqual(expectedList, lastFiveElements);
+
+        }
+    }
+}