diff --git a/gradebook/test/GradeBook.Tests/TypeTests.cs b/gradebook/test/GradeBook.Tests/TypeTests.cs
index a9a406e..be2fd45 100644
--- a/gradebook/test/GradeBook.Tests/TypeTests.cs
+++ b/gradebook/test/GradeBook.Tests/TypeTests.cs
@@ -6,6 +6,50 @@ namespace GradeBook.Tests
     using GradeBook;
     public class TypeTests
     {
+        [Fact]
+        public void CSharpCanPassByReference()
+        {
+            var book1 = GetBook("Book1");
+            GetBookSetName(ref book1, "New Name");
+
+            Assert.Equal(book1.Name, "New Name");
+        }
+
+        private void GetBookSetName(ref Book book, string name)
+        {
+            book = new Book(name);
+            book.Name = name;
+        }
+
+        [Fact]
+        public void CSharpIsPassByValue()
+        {
+            var book1 = GetBook("Book1");
+            GetBookSetName(book1, "New Name");
+
+            Assert.Equal(book1.Name, "Book1");
+        }
+
+        private void GetBookSetName(Book book, string name)
+        {
+            book = new Book(name);
+            book.Name = name;
+        }
+
+        [Fact]
+        public void CanSetNameFromReference()
+        {
+            var book1 = GetBook("Book1");
+            SetName(book1, "New Name");
+
+            Assert.Equal(book1.Name, "New Name");
+        }
+
+        private void SetName(Book book, string name)
+        {
+            book.Name = name;
+        }
+
         [Fact]
         public void GetBookReturnsDifferentObjects()
         {
@@ -16,6 +60,7 @@ namespace GradeBook.Tests
             Assert.Equal("Book2", book2.Name);
         }
 
+        [Fact]
         public void TwoVarsCanReferenceSameObject()
         {
             var book1 = GetBook("Book1");