What you did is proofing that google indexes hidden text. What you did not proof is how that impacts your ranking. Google will know that this text is hidden, although it is indexed and that is what is important.
replies(2):
https://support.google.com/webmasters/answer/66355?hl=en
I think they also use this to notify you in webmastertools when/if your site is hacked and is doing it to avoid detection by the normal user.
Here's the full "Don't do this sh!t" article from Google: https://support.google.com/webmasters/answer/35769#quality_g...