Add comparison to legacy counts (and adjust MaxEvents)

Trigger/TrigValidation/TrigP1Test/test/test_trigP1_v1Dev_newJO_build.py

@@ -12,6 +12,7 @@ ex = ExecStep.ExecStep()
 ex.type = 'athenaHLT'
 ex.job_options = 'TriggerJobOpts.runHLT'
 ex.input = 'data'
+ex.max_events = 50
 ex.flags = ['Trigger.triggerMenuSetup="Dev_pp_run3_v1_TriggerValidation_prescale"',
             'Trigger.doLVL1=True']
 
@@ -20,5 +21,14 @@ test.art_type = 'build'
 test.exec_steps = [ex]
 test.check_steps = CheckSteps.default_check_steps(test)
 
+# Add a step comparing counts against legacy reference (from test_trigP1_v1Dev_decodeBS_build)
+chaindump = test.get_step("ChainDump")
+chaindump.args = '--json --yaml ref_v1Dev_decodeBS_build.new'
+refcomp = CheckSteps.ChainCompStep("CountRefComp")
+refcomp.input_file = 'ref_v1Dev_decodeBS_build.new'
+refcomp.reference_from_release = True # installed from TrigP1Test/share
+refcomp.required = False # Final exit code doesn't depend on this step
+CheckSteps.add_step_after_type(test.check_steps, CheckSteps.ChainDumpStep, refcomp)
+
 import sys
 sys.exit(test.run())