You can't unless you ignore the result of the call. Which you can't do
if you don't want to change code. Which probably negates some other
tests you're doing.
I'd perhaps suggest you have a 'switch' to turn recaptcha on and off
in your code, and turn it off for any automated testing requiring any
'successful' recaptchas. Or create a wrapper object that either
displays/processes recaptcha or returns true.
--
PJH
'Two Dead in Baghdad' not 'product-friendly' - Kent Ertugrul, chief
executive of Phorm.