removed from CoffeeScript and from the description. Clojure did not have them, and the remaining languages are statically typed.

fixed + enabled JUnit5 + changed the method signature to return a primitive boolean instead of a wrapped Boolean

Removed in python.

added + chai assertions + removed non-integer inputs

From looking at the linked Wikipedia article, I believe this line, and the associated diagram, is not correct:

"For example, 6 is a triangle number because you can arrange 6 objects into an equilateral triangle:"

The reason 6 is a triangle number is because you can arrange 3 numbers in a triangle, 1, 2, and 3, and their total is 6.

(note that any non-integers, including non-number types, are not triangle numbers).

Mindless input validation is against the authoring guidelines, and the kata has already been translated to statically-typed languages where it does not apply. Tests should only pass positive integers.

Already removed in Ruby, JavaScript

Removed bools. (Sadly expecting True invalidates most solutions.)

note that any non-integers, including non-number types, are not triangle numbers

In Python, bool is an integer type:

isinstance(True, int) => True

I think that tests using bool should either expect True, or be removed for this language.

Sure thing!

Looks good.

Can you also add a return / pass statement in the initial solution function so it will not throw an error when executed?

def trace(matrix):
    # Your code here
    return 

Test framework update

Old test framework was only used in sample tests btw. I mostly just copied fixed tests there.

Test framework update

Done. Changed to:

test.assert_equals(num_to_russian("1000"), "тысяча")

1. Если уж тебе так нравится эта идея, я готов сделать и казахскую версию.

2. До этого (насколько я знаю), не было ни одной задачи на CodeWars в роде "переведи строку на {любой язык кроме английского} на число.". И да, я добавил слой сложности, с конвертированием числа в русскую строку. Не надо это упоминать.

3. Русская этимология отличается от этимологий многих других индо-европейских языков, поэтому это - новый опыт для носителей иностранных языков.

This test is incorrect from grammar perspective:

test.assert_equals(num_to_russian('1000'), "тысяч")

In Russian, тысяча is short for одна тысяча. Just as with одна целая, when talking about one of something, you have to consider gender. Interestingly, 1 000 is feminine, 1 000 000, 1 000 000 000 and onwards are masculine.

Acceptable versions:

test.assert_equals(num_to_russian('1000'), "одна тысяча")
test.assert_equals(num_to_russian('1000'), "тысяча")