Testing expects numerical NaNs and Infinitys, but does not check if normal digits are Strings or Numbers. It's not specified either.

It should be specified ( preferably as Numbers, though the Strings '-' and '.' grate ), and it should be tested.

I took out the floating point numbers ( and I fixed the typo in the random test headers ). I did not take out the negative zeroes; you can reverse engineer what is expected from testing.

This still does not make it a well-written or well-designed kata ( which is a shame really ), but at least it's solvable now.

Because the reference solution isn't even arbitrary precision real arithmetic, the answer derived by the reference solution is simply wrong. e.g:

1000000000000000 / 3896526038118073 =   
Expected:    '0.25663885990172302343866078834952392091192966443253258931043169884814443475859689408669779071203048'
instead got: '0.25663885990172302292589578160906176584827770888387331907749834099698695209475275668754975679175249'

The correct result is 0.25663885990172302292589578160906176584827770888387331907749834099698695209475275668754975679175249426790238934990... as shown by Wolfram Alpha:

http://www.wolframalpha.com/input/?i=1000000000000000+%2F+3896526038118073

Edit: as another demonstration of the incorrect behaviour, I tested some inputs where a === b, and the reference solution aren't even giving 1.0000...:

4413009194955343.5 / 4413009194955343.5 = 
Expected: '1.00000000000000018128219649179667453475071807778479860673338614478811930419432495701952533845572735'
instead got: '1.00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000'

2543978772493869.5 / 2543978772493869.5 = 
Expected: '9.99999999999999818307358842815939036168824334963639236381663286780869761669083041842512192848775626'
instead got: '1.00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000'

Needs tests with large initial dividend and a small divisor. Very large (or small) quotients aren't tested at all.

Since this is a kata about big decimal, the typical stuff should be banned, aka all the ways that can cause require('bignumber.js') to work.

Also there is no point in identifying -0. It's considered practically the same to everything except to Object.is, and even (-0).toString() gives 0. It's analogous to saying that all NaNs are equal, which is absurd, an artifact of IEEE floats standard and not a good practice in any means.

There is no point in getting digits below precision of a double, because they aren't even resolvable. Even a change in the tiniest significant bit in the divisor will cause the result to change significantly after the 16th digit (aka 1/Number.MAX_SAFE_INTEGER).

I don't think you really understand the intracacies of arbitrary precision real arithmetic. They simply aren't done this way. To begin with, passing numbers in as floating point values is already a grave mistake. They should be passed in as strings (but then this kata would be a duplicate to https://www.codewars.com/kata/divide-numbers-as-strings).

Random tests section titles has a typo: Things like -2345658712136251.5 = 7811398559714191 = should be -2345658712136251.5 / 7811398559714191 =.

Nice kata! Looks like it covers every possible edge case. Got me thinking quite a bit. And more over - this could be a useful function in many other applications!
Thanks

Thanks, by removing the print statements, it finally passed. :)

The second anti-cheat test rejects a code that contains any of re, sys, or print as an identifier (being a substring does not matter).
The tests show the input numbers, so you won't need to print in order to debug.

I'll update the description to make the point clear.

I'm trying to use Python to solve this kata. All tests passed except the second test in Anti-cheating checks which shows that You're asking for trouble..., but I'm not hard coding the answer and the total length of the solution is under 5,000 characters, is this a bug or just my problem?

Fixed. Also added info in the description about which characters are allowed.

Using non-capturing groups in js gives the error: Contains illegal characters ...