Additional keyword tests

[epoberezkin]

@Julian as discussed in #253 (comment), I've added several tests for keywords. There are more tests for $ref and some other special cases that are not limited to ajv (I will make separate PRs).

What I meant by implementation specific tests, see these two for example:

• https://github.com/epoberezkin/ajv/blob/master/spec/tests/rules/oneOf.json#L51
• https://github.com/epoberezkin/ajv/blob/master/spec/tests/rules/uniqueItems.json

Ajv has performance optimisation that these tests invoke. They are not in this PR - I don't think they should be here, but let me know what you think.

[Julian]

That's a lot to review :D -- but thanks! Definitely looks super useful. Will see what I can get through.

And yeah I think the performance ones make sense not to include -- FWIW, in my validator what I do is just run performance tests over all the tests that are here, but it definitely sounds reasonable to have large examples to really exercise things -- would agree here is not the best place though (I have some of those, but yeah they are definitely separate from the suite).

[Julian]

OK, but not that bad given it's just the same tests for the 3 drafts more or less.

Cool, lgtm! Merging.

[epoberezkin]

FWIW, in my validator what I do is just run performance tests over all the tests that are here, but it definitely sounds reasonable to have large examples to really exercise things -- would agree here is not the best place though (I have some of those, but yeah they are definitely separate from the suite).

What I mean is that validation code in my case would be different depending on the schema - e.g. uniqueItems is usually O(n2) time, but if items must have scalar types it would use hash with O(n) time... Anyway, I will only submit generic tests.

[awwright]

Wait, did this check in an entire dependency?

[Julian]

@awwright not a new dependency -- this just merged in some additional (edge case) tests that @epoberezkin had in his validator but not upstream. Make sense, or does something look off?

[awwright]

@Julian That makes sense!