• Why is the solution defined in the class of the tests???? that's not testing the user's code.
• anything close to the ref solution must be private.

I'll reject this one because of the problem with the test holding the solution. Too risky to keep that around. You can either create a new one or fork this one to make the required modifications.

'think so.

Looks to me like the tables' headers are a bit misleading:

• "product of" describes how one value in one row is built
• the left column actually shows the value for that product...
• ... while the header is closure({2,3}), which is actually the whole possible values (hence rows) together.

So, in my comprehension, closure({2,3}) should be the title of the whole table, and not the header of one column. Same kind of problems goes with the second table (but not exactly the same, since the information is organized a bit differently)

edit: I'd even give the products first, then the values in a second column. But that's a matter of preferences, at this point.

spoiler flag, please...

Implement testing that would force solutions to run in sub-linear time

no. As you pointed out, this is white. There shouldn't be performances requirements here. Rather:

• at worst, the info should get removed from the description
• at best, the kata should be retired because it's just a duplicate of many other kata.

edit: ok, I got a coffee in the belly, and now I see the previous line in your message... x) ->
I'd stick to point 2, though

never a comma before a "and" (yes, it's grammatical, but still about the kata)

 "1 hour and 1 second"
        ^
 "1 year, 11 months, 4 days, 8 hours, 10 minutes, and 42 seconds"
                                                ^

This is inconsistent/not logical (from the description).

A justification doesn't mean it's good/acceptable. The kata is about creating human friendly output. This is not human friendly output.

 "1 hour and 1 second"
        ^
 "1 year, 11 months, 4 days, 8 hours, 10 minutes, and 42 seconds"
                                                ^

This is inconsistent/not logical (from the description).

Hi,

I don't do rust myself, so I cannot tell. That test uses a macro, and this specific test is only closing the instance, without calling any other method (afaict...).

yeah, that one is the issue from years ago that is still opened. It's chemically incorrect, but considering the task, it's still doable (numerically/mathematically) without problems on user's side (as long as they stick to the task only)

edit: and numerically, it shoud have 0 H, so. But again, the molecule cannot exist, yeah.

That's a cheat. Don't use that.

ffs, I thought I had fixed that... x/ Yes, it should be "propenoyl..."

random tests, I guess?

except the test is not on ans...

You should explain the math notations: not all users have a math-college background (hint: I don't ;) )

Also names are not to be chosen randomly. If you can switch the function name from sum_not_prime to sum_prime without changing anything else, this means the name has nothing to do with the task (or one of them is totally wrong).