• Ruby 3.0 should be enabled (Refer this & this for more detail)

No random tests in CS

The function name should be in snake_case in Python and Ruby.

No random tests in Python.

Ruby version needs random tests

Interesting kata. I'd recommend adding examples in the Description, as well, rather than having the user decipher it from the test cases.

For example, a sentence like:
"Given a sentence and number N in the argument, output the CSS, followed by the HTML with each word in the sentence. Each word is separated by a space and the HTML should apply only to the Nth character.

JS version needs random tests

Needs random tests.

Nice kata, calendars and dates are always fun with edge cases, but...

Ooops! The Python version of the test code does not expect output in the format given in the examples.

The example in the description:

callBack('Mr Pink', 15/07/2015,'in 6 days') 
// so call back Mr Pink  in 6 days.
=> "Call back Mr Pink on Tuesday 21st July 2015"

When the actual expected result contains additional punctuation, the order of the month and day are reversed and the day number component is loses the date ordinal ('st', 'nd', 'th') and retains a leading zero, like so:

So these expected outputs:

Call back Mr Pink on Tuesday 21st July 2015
Call back Mr White on Wednesday 1st July 2015

Are actually expected to be:

Call back Mr Pink on Tuesday, July 21, 2015
Call back Mr White on Wednesday, July 01, 2015