PDB-106 add unit test for processing of reports with empty metrics hash (failed reports)
PDB-106: return 0 run_duration for failed runs, rather than hitting an exception
PDB-106 instead of setting run_duration to 0 on reports with no metrics (failed run), raise an error
PDB-106 Reword error message

Signed-off-by: Ken Barber <ken@bob.sh>
Merge branch 'PDB-106' into 1.5.x

* PDB-106:
  PDB-106 Reword error message
  PDB-106 instead of setting run_duration to 0 on reports with no metrics (failed run), raise an error
  PDB-106: return 0 run_duration for failed runs, rather than hitting an exception
  PDB-106 add unit test for processing of reports with empty metrics hash (failed reports)