Throw exception when incomplete sessions definitions are given in def-rules-test

[WilliamParker]

Def-rules-test currently silently ignores session definitions that don't come in tuples of 3. So for example:

(def-rules-test example-test
      {:rules [my-rule ...]
       :sessions [empty-session [my-rule]]}

This will compile but no empty-session will be created. The reason for this is that the implementation uses partition with n=3 and items not fitting into multiples of three are simply discarded.

clara.test-rules> (partition 3 [:a :b])
()
clara.test-rules> (partition 3 [:a :b :c :d])
((:a :b :c))

It would be better to throw an exception and fail to compile if the number of items in the :sessions vector is not a multiple of 3. For reference, the expected input form is

{:sessions [session-name production-names-vec session-options]}

[Zylox]

Well that sure is an annoying way of doing updates, isn't it github.

But anyway, as github alluded to, im taking a crack at it. Tests are being surprisingly obnoxious to write, just need to spend more time on it.

[Zylox]

@WilliamParker I have some questions about some other assertions we may want to do.

Does it make sense for sessions to be empty? Looking at the general purpose and doc of the util, it seems like it should always have something, but maybe im missing something.

Additionally, do we also want to validate the forms themselves. For example, something like

 :queries [query1 [[]
                   [[Cold (= ?t temperature)]]
                   []
                   []]]

works at present since the destructuring will ignore additional fields. Given the 'vector madness' i could see these tests getting into, something more important might slip through. similar things apply to :rules and :sessions.

[WilliamParker]

Somehow I missed when you tagged me @Zylox - I'm just seeing your comment now when looking at this again after a few years. :( Sorry about that, feel free to tag/message me if that happens again.

What you did looks fine at first glance, my thoughts on a first pass at this were just to validate the number of forms passed in. If they are invalid then I'd expect session creation to fail, and if it doesn't validation there could be improved. At any rate some validation is better than none.

I can plan to make this into a PR (and set the Git user on it to you) or this looks OK as a PR base to me if you'd like to create one. At first glance this looks OK but there might be something to fix after a closer look. Since it is a test-only change that won't e.g. cause tests to not run I'm not super concerned about it though.