tree 511a36c6e88e1ea5199921be0df8d3960002748e
parent 2ae827a8d28dd586233036a4bc3a09320c82dd34
author Shawn McCarney <shawnmm@us.ibm.com> 1712357769 -0500
committer Shawn McCarney <shawnmm@us.ibm.com> 1712621723 -0500

pseq: Add presence caching to Services

Add caching of hardware presence data to the Services class in the
phosphor-power-sequencer application.  Obtaining hardware presence from
D-Bus is a slow operation.  During pgood fault isolation, multiple rails
may need the same hardware presence information.  Cache this information
to improve performance.

Provide a method to clear the cached data since it is only valid for a
short period of time.  For example, power supplies are hot-pluggable, so
their presence may change while a system is powered on.

Tested:
* BMCServices
  * createPMBus()
    * Verify correct sysfs path passed to PMBus constructor
  * isPresent()
    * Test where hardware is present
      * Test where value is not cached
        * Verify value is cached after data obtained from D-Bus
      * Test where value is cached
    * Test where hardware is not present
      * Test where value is not cached
        * Verify value is cached after data obtained from D-Bus
      * Test where value is cached
    * Test where D-Bus method call fails with an expected exception
      * Verify false is stored in cache
      * Verify false is returned
    * Test where D-Bus method call fails with an unexpected exception
      * Verify nothing is cached
      * Verify exception is re-thrown
  * clearCache()
    * Verify clears all cached data
* MockServices
  * Verify all methods can be called from an automated test
* Run existing automated tests

Change-Id: I3e92be3ded1ed333acbedc970409176cabe98c09
Signed-off-by: Shawn McCarney <shawnmm@us.ibm.com>