diff --git a/X10D.Tests/src/Collections/EnumerableTests.cs b/X10D.Tests/src/Collections/EnumerableTests.cs
new file mode 100644
index 0000000..5cd9dc0
--- /dev/null
+++ b/X10D.Tests/src/Collections/EnumerableTests.cs
@@ -0,0 +1,34 @@
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+using X10D.Collections;
+
+namespace X10D.Tests.Collections;
+
+[TestClass]
+public class EnumerableTests
+{
+    [TestMethod]
+    public void EnumerableShuffledShouldBeDifferentOrder()
+    {
+        var list = new List<int>
+        {
+            1,
+            2,
+            3,
+            4,
+            5
+        };
+        var shuffled = new List<int>(list);
+
+        CollectionAssert.AreEqual(list, shuffled);
+
+        shuffled = new List<int>(list.Shuffled());
+
+        CollectionAssert.AreNotEqual(list, shuffled);
+    }
+
+    [TestMethod]
+    public void NullShuffledShouldThrow()
+    {
+        Assert.ThrowsException<ArgumentNullException>(() => ((List<int>?)null)!.Shuffled());
+    }
+}
diff --git a/X10D.Tests/src/Collections/ListTests.cs b/X10D.Tests/src/Collections/ListTests.cs
new file mode 100644
index 0000000..135a485
--- /dev/null
+++ b/X10D.Tests/src/Collections/ListTests.cs
@@ -0,0 +1,57 @@
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+using X10D.Collections;
+
+namespace X10D.Tests.Collections;
+
+[TestClass]
+public class ListTests
+{
+    [TestMethod]
+    public void ListShuffleShouldReorder()
+    {
+        var list = new List<int>
+        {
+            1,
+            2,
+            3,
+            4,
+            5
+        };
+        var shuffled = new List<int>(list);
+
+        CollectionAssert.AreEqual(list, shuffled);
+
+        shuffled.Shuffle();
+
+        CollectionAssert.AreNotEqual(list, shuffled);
+    }
+
+    [TestMethod]
+    public void ListRandomShouldReturnExistingObject()
+    {
+        var list = new List<int>
+        {
+            1,
+            2,
+            3,
+            4,
+            5
+        };
+
+        int random = list.Random();
+
+        Assert.IsTrue(list.Contains(random));
+    }
+
+    [TestMethod]
+    public void NullShuffleShouldThrow()
+    {
+        Assert.ThrowsException<ArgumentNullException>(() => ((List<int>?)null)!.Shuffle());
+    }
+
+    [TestMethod]
+    public void NullRandomShouldThrow()
+    {
+        Assert.ThrowsException<ArgumentNullException>(() => ((List<int>?)null)!.Random());
+    }
+}
diff --git a/X10D.Tests/src/Core/EnumerableTests.cs b/X10D.Tests/src/Core/EnumerableTests.cs
index a048c0d..3e37d55 100644
--- a/X10D.Tests/src/Core/EnumerableTests.cs
+++ b/X10D.Tests/src/Core/EnumerableTests.cs
@@ -1,4 +1,5 @@
 using Microsoft.VisualStudio.TestTools.UnitTesting;
+using X10D.Collections;
 
 namespace X10D.Tests.Core;
 
diff --git a/X10D/src/Collections/EnumerableExtensions.cs b/X10D/src/Collections/EnumerableExtensions.cs
index 02f4f66..64c770e 100644
--- a/X10D/src/Collections/EnumerableExtensions.cs
+++ b/X10D/src/Collections/EnumerableExtensions.cs
@@ -3,7 +3,7 @@
 /// <summary>
 ///     Extension methods for <see cref="IEnumerable{T}" />.
 /// </summary>
-public static partial class EnumerableExtensions
+public static class EnumerableExtensions
 {
     /// <summary>
     ///     Reorganizes the elements in an enumerable by implementing a Fisher-Yates shuffle, and returns th shuffled result.