diff --git a/JsonGeneratorTests/JsonValueTests.cpp b/JsonGeneratorTests/JsonValueTests.cpp
index d9671980..3a2788b5 100644
--- a/JsonGeneratorTests/JsonValueTests.cpp
+++ b/JsonGeneratorTests/JsonValueTests.cpp
@@ -10,6 +10,7 @@ namespace JsonGeneratorTests
     {
         char buffer[20];
         StringBuilder* sb;
+        size_t returnValue;
 
     public:
 
@@ -26,58 +27,76 @@ namespace JsonGeneratorTests
         TEST_METHOD(Null)
         {
             append((char*)0);
+
+            assertReturns(4);
             assertResultIs("null");
         }
 
         TEST_METHOD(EmptyString)
         {
             append("");
+
+            assertReturns(2);
             assertResultIs("\"\"");
         }
 
         TEST_METHOD(OneString)
         {
             append("ABCD");
+            assertReturns(6);
             assertResultIs("\"ABCD\"");
         }
 
         TEST_METHOD(OneTwoStrings)
         {
             append("ABCD");
+            assertReturns(6);
+
             append("EFGH");
+            assertReturns(6);
+            
             assertResultIs("\"ABCD\"\"EFGH\"");
         }
 
         TEST_METHOD(OverCapacity)
         {
             append("ABCDEFGHIJKLMNOPQRSTUVWXYZ");
+            assertReturns(19);
             assertResultIs("\"ABCDEFGHIJKLMNOPQR");
 
-            append("");
+            append("ABC");
+            assertReturns(0);
             assertResultIs("\"ABCDEFGHIJKLMNOPQR");
         }
 
         TEST_METHOD(SpecialChars)
         {
             append("\\\"\b\f\n\r\t");
+            assertReturns(16);
             assertResultIs("\"\\\\\\\"\\b\\f\\n\\r\\t\"");
         }
 
         TEST_METHOD(Number)
         {
             append(3.14);
+            assertReturns(4);
             assertResultIs("3.14");
         }
 
         template<typename T>
         void append(T value)
         {
-            JsonValue(value).writeTo(*sb);
+            returnValue = JsonValue(value).writeTo(*sb);
         }
 
         void assertResultIs(const char* expected)
         {
             Assert::AreEqual(expected, buffer);
         }
+
+        void assertReturns(size_t expected)
+        {
+            Assert::AreEqual(expected, returnValue);
+        }
     };
 }
\ No newline at end of file