Optimize testing guide hierachy

Change-Id: Idee00660c904f54ebdb15f2bcd00b79d595d479e
diff --git a/testing.rst b/testing.rst
index 70ba36d..76f83fd 100644
--- a/testing.rst
+++ b/testing.rst
@@ -1,9 +1,6 @@
 Testing Guide
 =============
 
-Test Infrastructure Overview
-----------------------------
-
 We implemented multiple types of tests in SD-Fabric.
 
 - **Unit Test**
@@ -26,9 +23,10 @@
   :width: 800px
 
 .. toctree::
-   :maxdepth: 2
-   :glob:
+  :maxdepth: 2
+  :hidden:
+  :glob:
 
-   testing/component
-   testing/pipeline
-   testing/system
+  testing/component
+  testing/pipeline
+  testing/system