I used to give all new employees going into certain departments an Ishihara colour test. It's an interesting test and throws up some interesting results but it isn't a catch all and real world colours and lighting and who perceives what are also things to consider.
I had a book rather than an online test and it had some plates in which the numbers shouldn't be visible to a normally sighted person. There's on online test you can do here...
https://www.colour-blindness.com/colour-blindness-tests/ishihara-colour-test-plates/
In industry if you're relying on a human some women seem to have a much superior ability to see differences in certain shades. Some theorise that this goes back to the hunter gatherer days when men really didn't need an advanced colour perception ability (it really doesn't matter too much if a man can't perceive subtle differences in wildebeest or boar colouration, they all taste the same) but women tended to be picking berries and roots and things and colour perception maybe mattered more to them.