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.cpp b/physical.cpp
index d15cfcd..2be9e14 100644
--- a/physical.cpp
+++ b/physical.cpp
@@ -57,6 +57,11 @@
     return;
 }
 
+auto Physical::state() const -> Action
+{
+    return sdbusplus::xyz::openbmc_project::Led::server::Physical::state();
+}
+
 auto Physical::state(Action value) -> Action
 {
     auto current =