No matter what I pass into the guess method (Ruby version), I get a NoMethodError:

 `guess': undefined method `>=' for nil:NilClass (NoMethodError)
	from `get_number'
	from  `block in 
'
	from  `each'
	from  `
'

Is there a way to see the sample test cases when actually doing the kata though? I couldn't find one without clicking over to the discussion and risking spoilers.

There are a LOT of test cases that aren't covered in the example.

It should say that "3" should come out to 3, "3 4" should come out to 4, and "2 -" should come out to -2.