depends on the gas company,,,some do bends,,,some do film,,,some do both,,,some do mag particle,,,some do dye pen,,,some do all!!!! just depends on the gas company man.

Table 3.8 of D1.2 requires none for welder/operator qualification
Welders are qualified also if they weld up a procedure qualification ttest and it past, this includes a tensil test, so this may be what's confusing the issue for you. This is to chedk the properties of the material and has nothing to do with the welders abilities, to say.