Ok I understood

issue with your code, closing (cannot use ==)

It was javascript, fixed.

Already reported in the post below.

.

Nope, there is nothing like that.

BTW, how do you know?

Quite obvious from the error message:

main.rb:15:in `block (2 levels) in <main>': undefined method `>' for nil:NilClass (NoMethodError)
	from main.rb:5:in `block in find_index'
	from main.rb:4:in `each'
	from main.rb:4:in `find_index'
	from main.rb:15:in `block in <main>'
	from /runner/frameworks/ruby/cw-2.rb:55:in `block in describe'
	from /runner/frameworks/ruby/cw-2.rb:46:in `measure'
	from /runner/frameworks/ruby/cw-2.rb:51:in `describe'
	from /runner/frameworks/ruby/cw-2.rb:202:in `describe'
	from main.rb:11:in `<main>'

Not a kata issue.

Which language?

Read this

Empty string isn't tested in Python, it should be added as a fixed test.

Not a suggestion.

Zeroes are neither positive nor negative. Not sure if that helps

thank you question and answer, i understood ,

Test suite was missing #include <math.h>. Fixed.