This page uses the methods described in A Sentinel for Detecting Trusted Keys in DNSSEC
to determine if the resolvers that you are using will survive the upcoming KSK roll.
You should really read the document, but the 50'000ft view is that it attempts to load resources from 3 names:
It then uses some simple logic to tell what your fate will be after the KSK roll:
This work by Warren Kumari is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.