I see from your past posts that you may be working with telepower supplies for cell towers etc.
If these are usually connected to batteries, the battery can be part of the ripple and noise filter.
If so a good battery of the specific type would be needed for testing.
In my day, I did some testing on telepower:
for ripple and noise: with a
https://en.wikipedia.org/wiki/Psophometer looking like the one in photo in there.
for conducted emi on both sides: with a spectrum analyser and termination.
The testing was done by the vendor, usually witnessed by the purchaser.
There are Test Equipment rental companies in USA and Canada that I have used to rent test equipment, although not the items above.
The advantage of renting is that purchase is not necessary for infrequently used TE, and the units are delivered in calibration and working.
If you actually need an independent test, I suggest to try the a provider in your area of test services to the electrical utilities.