This is a very nice feature in jqwik

Question

This is a very nice feature in jqwik also the way assumptions return an error if too many possibilities were skipped and in general having some stats printed like there would add tons of value to property testing in kotest it would make it much easier to make tests

Jonathan Olsson · Answer

Yeah they have similar stuff in eqc and proper in the erlang world I assume jqwik as well has the possibility to attribute weights to the different actions as well i e if one action due to preconditions gets executed too infrequently

Jonathan Olsson · Answer

Only having looked superficially jqwik appears pretty full featured and competent But I really don t like the annotations smile

dave08 · Answer

I m not really familiar with jqwik I was just looking through the docs after you mentioned it and I found some features that would be GREAT in kotest but I don t like more than just the annotations there it s just not Kotlinish and the issue for Kotlin support s been around for a few months with no love

dave08 · Answer

The fact that they require using their runner for the tests is a big thumbsdown skin tone 3 for me I like Kotest for a bunch of reasons and wouldn t abandon it too quickly

dave08 · Answer

There seems to be `classify ` and `checkCoverage ` for assumptions already thinking face

dave08 · Answer

But I wonder if it can print that out without the check coverage

sam · Answer

What are you looking for in reporting that classify doesn t already do

dave08 · Answer

Say this example from jqwik ``` Property void simpleStats ForAll RoundingMode mode Statistics collect mode will create an output similar to that MyTest simpleStats 1000 statistics = FLOOR 158 16 HALF EVEN 135 14 DOWN 126 13 UP 120 12 HALF UP 118 12 CEILING 117 12 UNNECESSARY 117 12 HALF DOWN 109 11 ```

sam · Answer

So you re looking for automatic labelling

sam · Answer

I assume that only works on a couple of types

dave08 · Answer

It gives a nice report not only when checking coverage and automatic labelling is a plus

sam · Answer

Easy enough to do for numbers and enums

dave08 · Answer

That way when making the tests one can ensure that the distribution is enough to cover all cases

dave08 · Answer

Automatic labelling would make it even easier

sam · Answer

I m not sure i see the benefit Is it to check the platforms random is actually random

sam · Answer

Also kotest has this great feature of edgecases that other prop tests don t have

sam · Answer

We can add it though

dave08 · Answer

gt Is it to check the platforms random is actually random No rather to make sure that filtering and all other steps produce a reasonable amount of variants The programmer s errors not the framework And edgecases need to be contrived and when you don t know when they re already covered by the random ones sufficiently it s not so easy to do in more complicated setups

sam · Answer

Ok

sam · Answer

I ll put it in the roadmap

dave08 · Answer

Thanks wink I looked up alternatives you re really doing great work with Kotest I hope all these requests are OK I guess I could do it on my end using the `PropertyContext` I just supposed others could benefit from this I would make a PR but I m not familiar with MPP and how you would like this to be done

dave08 · Answer

I guess the easiest way to do it would be something like ``` fun PropertyContext printResult val attempts = attempts toDouble classifications forEach labelled occurences gt val percent = occurences toDouble attempts 100 0 println $labelled $occurences $ percent roundToInt ```

sam · Answer

The more requests the better Keep em coming

dave08 · Answer

And then prepend it to checkAll printResult

dave08 · Answer

And classifying enums ```inline fun lt reified T Enum lt T gt gt PropertyContext classify label T classify label name ``` the wonders of kotlin extension functions grin I made my own classifiers too for domain specific uses this might be nice to document

sam · Answer

< dave08> <https github com kotest kotest pull 2426>

dave08 · Answer

Very nice ok hand skin tone 3