Regardless of that. The situation places an individual directly in front of energized equipment when testing/troubleshooting WITHOUT proper clearances.
Chevy -- what the code requires & a personal opinion to me are different scenarios -- I see that 2 have agreed that there is a violation of 110.26(A) which has always been a debatable scenario on this forum.
( A) Working Space. Working space for equipment operating at 600 volts, nominal, or less to ground and
likely to require examination, adjustment, servicing, or maintenance
while energized shall comply with the dimensions of 110.26(A)(1), (A)(2), and (A)(3) or as required or permitted elsewhere in this
Code.
If you are able to turn of power to the equipment with a non fused disconnect within sight then the equipment is not energized -- How you test fuses, transformers, relays, contactors is your choice & I would agree that testing live is more convienient but is not a requirement. Would you require a single pole switch (a non fused disconnect) that is within sight then the equipment (say a sprinkler control) in a crawlspace, to be readily accessible with clearances?
That said, if your OCPD is not readily acessible with the ability to lock off and your disconnect was fused I would interprete that there is a violation of 110.26(A). I do not disagree with your safety concerns but per NEC I believe what you have described may be boarderline, but is a compliant install.
There a many scenarios that could change my interpretatioin -- for instance what is the rating of the disconnects 15 amp -- 400 amp? clearly could change the protocol on testing.