diff --git a/gradebook/test/GradeBook.Tests/TypeTests.cs b/gradebook/test/GradeBook.Tests/TypeTests.cs
index be2fd45..7b63549 100644
--- a/gradebook/test/GradeBook.Tests/TypeTests.cs
+++ b/gradebook/test/GradeBook.Tests/TypeTests.cs
@@ -6,6 +6,40 @@ namespace GradeBook.Tests
     using GradeBook;
     public class TypeTests
     {
+        [Fact]
+        public void ValueTypesAlsoPassByValue()
+        {
+            var x = GetInt();
+            Assert.Equal(3,x);
+
+            SetInt(ref x);
+            Assert.Equal(42, x);
+        }
+
+        private void SetInt(ref int x)
+        {
+            x = 42;
+        }
+
+        private int GetInt()
+        {
+            return 3;
+        }
+
+        [Fact]
+        public void StringsBehaveLikeValueTypes()
+        {
+            string name = "Jason";
+            MakeUppserCase(name); // try to change String like a reference
+
+            Assert.Equal("Jason", name); // ToUpper does not work on String, although it's reference. It's copied as value
+        }
+
+        private void MakeUppserCase(string arg)
+        {
+            arg.ToUpper();
+        }
+
         [Fact]
         public void CSharpCanPassByReference()
         {