tree f84751a82f36f37bd51326d2539c98f1f6bc4be7
parent 48033bf62871ac8c2572cebdfb4d5aab31e41f71
author Shawn McCarney <shawnmm@us.ibm.com> 1612042558 -0600
committer Shawn McCarney <shawnmm@us.ibm.com> 1612047910 -0600

regulators: Handle expected D-Bus exceptions

When hardware is not present, it can appear multiple ways on D-Bus:
* Object path does not exist
* Object path exists, but Inventory.Item interface not implemented
* Inventory.Item interface implemented with Present value of false

The first two cases result in a D-Bus exception being thrown when trying
to obtain the value of the Present property.

Enhance the DBusPresenceService class to catch these exceptions and
treat them as a false Presence value.

Tested:
* Tested where hardware present
* Tested where hardware not present
  * Object path and interface/property exist
  * Object path exists
  * Object path does not exist
* For full test plan, see
  https://gist.github.com/smccarney/d3d7384700abcc5abf436e2b859d98e5

Signed-off-by: Shawn McCarney <shawnmm@us.ibm.com>
Change-Id: I543a4c16984dea3657b8024dedd1060dda4319e2