Pressure testing has mixed support. There was an argument against it because it could cause growth of subcritical cracks. So , theoretically , several pressure tests could grow a subcritical crack up to critical size. And , at least in older steels , there was "strain-age-embrittlement" . Where near a sub-critical defect ,there could be plastic deformation during a pressure test, the strained metal would loose toughness with time ( years ). I tested steels made in the 50 and 60's ( from failures of old pipelines). By cold rolling them 5 % then aging at about 300 F for 24 hr, then doing Charpy tests. Some steels showed a significant loss of toughness. And ,yes, you can say that is not what really happens in a pipe.
