Add test cases to validate state of physical LED

This commit adds code that verifies the state of
physical LED is appropriately set in various cases

Change-Id: I9eab752f6f2b47e719934c14ef95e775d36bcaa0
Signed-off-by: Vishwanatha Subbanna <vishwa@linux.vnet.ibm.com>
diff --git a/physical.hpp b/physical.hpp
index 383c98a..4242952 100644
--- a/physical.hpp
+++ b/physical.hpp
@@ -67,6 +67,12 @@
      */
     Action state(Action value) override;
 
+    /** @brief Overriden State Property Getter function
+     *
+     *  @return  -  One of OFF / ON / BLINK
+     */
+    Action state() const override;
+
   private:
     /** @brief Associated LED implementation
      */