Added "is_object" into the list of unit tests capable of being run.
diff --git a/user_guide/libraries/unit_testing.html b/user_guide/libraries/unit_testing.html
index 2166607..a30343f 100644
--- a/user_guide/libraries/unit_testing.html
+++ b/user_guide/libraries/unit_testing.html
@@ -104,6 +104,7 @@
 as the result.  Here is a list of allowed comparison types:</p>
 
 <ul>
+<li>is_object</li>
 <li>is_string</li>
 <li>is_bool</li>
 <li>is_true</li>