Thanks for the clarification.

thanks, fixed!

Sample tests still uses validCheckmate instead of valid_checkmate.

done!

I think I have fixed all of them

Thanks for feedback, working on it!

Thank you for finding this, working on fixing ASAP

I don't understand the results of the following five "Edge cases" as I believe in all cases that the Black King is in checkmate.

['0', '0', '0', '0', '0', '0', '0', '0']

['0', '0', '0', '0', '0', '0', '0', '0']

['0', '0', '0', '0', '0', '0', '0', '0']

['0', '0', '0', '0', '0', '0', '0', '0']

['0', '0', '0', '0', '0', '0', '0', '0']

['Q', 'W', '0', '0', '0', '0', '0', '0']

['0', '0', '0', '0', '0', '0', '0', '0']

['0', 'B', '0', '0', '0', '0', '0', '0']

Black King= [7, 1] White King= [5, 1] White Queen= [5, 0]
True should equal False

['0', '0', '0', '0', '0', '0', '0', '0']

['0', '0', '0', '0', '0', '0', '0', '0']

['0', '0', '0', '0', '0', '0', '0', '0']

['0', '0', '0', '0', '0', '0', '0', '0']

['0', '0', '0', '0', '0', '0', '0', '0']

['0', '0', '0', '0', '0', '0', '0', '0']

['0', '0', 'Q', '0', '0', '0', 'W', '0']

['0', '0', '0', '0', 'B', '0', '0', '0']

Black King= [7, 4] White King= [6, 6] White Queen= [6, 2]
True should equal False

['0', '0', '0', '0', '0', 'B', '0', '0']

['0', '0', '0', 'W', '0', '0', '0', '0']

['0', '0', '0', '0', '0', '0', 'Q', '0']

['0', '0', '0', '0', '0', '0', '0', '0']

['0', '0', '0', '0', '0', '0', '0', '0']

['0', '0', '0', '0', '0', '0', '0', '0']

['0', '0', '0', '0', '0', '0', '0', '0']

['0', '0', '0', '0', '0', '0', '0', '0']

Black King= [0, 5] White King= [1, 3] White Queen= [2, 6]
True should equal False

['B', '0', 'W', '0', '0', '0', '0', '0']

['0', '0', '0', '0', '0', '0', '0', '0']

['0', 'Q', '0', '0', '0', '0', '0', '0']

['0', '0', '0', '0', '0', '0', '0', '0']

['0', '0', '0', '0', '0', '0', '0', '0']

['0', '0', '0', '0', '0', '0', '0', '0']

['0', '0', '0', '0', '0', '0', '0', '0']

['0', '0', '0', '0', '0', '0', '0', '0']

Black King= [0, 0] White King= [0, 2] White Queen= [2, 1]
True should equal False

['0', '0', '0', '0', 'B', '0', '0', '0']

['0', '0', 'W', '0', '0', '0', 'Q', '0']

['0', '0', '0', '0', '0', '0', '0', '0']

['0', '0', '0', '0', '0', '0', '0', '0']

['0', '0', '0', '0', '0', '0', '0', '0']

['0', '0', '0', '0', '0', '0', '0', '0']

['0', '0', '0', '0', '0', '0', '0', '0']

['0', '0', '0', '0', '0', '0', '0', '0']

Black King= [0, 4] White King= [1, 2] White Queen= [1, 6]
True should equal False

There seem to be some invalid test cases:

[
  ['0', '0', '0', '0', '0', '0', '0', '0'],
  ['B', 'Q', '0', '0', '0', '0', '0', '0'],
  ['0', '0', '0', '0', '0', '0', '0', '0'],
  ['0', '0', 'W', '0', '0', '0', '0', '0'],
  ['0', '0', '0', '0', '0', '0', '0', '0'],
  ['0', '0', '0', '0', '0', '0', '0', 'W'],
  ['0', '0', '0', '0', '0', '0', '0', '0'],
  ['0', '0', '0', '0', '0', 'Q', '0', 'B']
]

The discription mixes "space" and "whitespace" in an unclear manner.

Leading and trailing whitespace is also allowed.

yet

It should NOT match: "abc\n"

I suppose it depends on context, but from a regex perspective, I would assume "whitespace" refers to \s. I would just change everything to "spaces" for clarity.

lol

not a good practice as we are splitting the string and indexing it at each iteration while it can be done only once