Add Prepend method and tests #56

ShittyLINQ/Prepend.cs

@@ -0,0 +1,21 @@
+namespace ShittyLINQ
+{
+    using System;
+    using System.Collections.Generic;
+
+    public static partial class Extensions
+    {
+        public static IEnumerable<T> Prepend<T>(this IEnumerable<T> source, T element)
+        {
+            if (source == null)
+                throw new ArgumentNullException(nameof(source));
+
+            yield return element;
+
+            foreach (var item in source)
+            {
+                yield return item;
+            }
+        }
+    }
+}

ShittyLinqTests/PrependTests.cs

@@ -0,0 +1,32 @@
+namespace ShittyTests
+{
+    using Microsoft.VisualStudio.TestTools.UnitTesting;
+    using ShittyLINQ;
+    using ShittyTests.TestHelpers;
+
+    [TestClass]
+    public class PrependTests
+    {
+        [TestMethod]
+        public void Prepend_ReturnsExpected()
+        {
+            var source = new[] { 1, 2, 3, 4, 5 };
+            var expectedResult = new[] { 0, 1, 2, 3, 4, 5 };
+
+            var result = source.Prepend(0);
+
+            TestHelper.AssertCollectionsAreSame(expectedResult, result);
+        }
+
+        [TestMethod]
+        public void Prepend_ReturnsExpectedWithEmptyCollection()
+        {
+            var source = new int[] { };
+            var expectedResult = new int[] { 0 };
+
+            var result = source.Prepend(0);
+
+            TestHelper.AssertCollectionsAreSame(expectedResult, result);
+        }
+    }
+}