What is this go-no go function in some oscilloscopes and how can I use it?
See Mask Limit Testing


  Capture a signal from a known working system, and [the oscilloscope] will draw a mask around it with your specified tolerance. Connect the system under test, and [the oscilloscope] will highlight any parts of the waveform that fall outside the mask area. 


This can be used to check for intermittent problems.


From Agilent

Some scopes have a pass/fail output that can be used in automated testing.