The people I spoke to verify that they have the correct air and power for our system and that it provides the expected outputs.  Pass, fail, busy and associated light and/or audible  indications.  They add the tester to their PM schedule and it is ready to use.  This may vary by company but my survey of two companies found the same processes in place.

The tester is used on a statistical sample of known good parts to make sure that it produces a repeatable result.  Some customers take that result and add 3 standard deviations and use that as the reject set point.  If a leak rate is defined the tester is measured with a known leak standard to make sure that the results are repeatable.  If no leak standard is available but a challenge sample is the same process is used to record decay values and create a reject level.

Once the IQ and OQ are completed a performance qualification is performed by taking the developed parameters and testing several lots of known parts to make sure that good parts pass and bad parts fail.  Once this is done they can be reasonably confident that the tester will perform as expected and it can be released to production.