I wanted to know, what will happen, if the testversion of photoshop ist over...do they extend it automatically, so I have to pay?
No. It will simply cease to function and offer to sign up for a paid subscription.
After the 30 day trial ends you must pay to continue using the program
Cloud Plans https://creative.adobe.com/plans
-Special Photography Plan includes Photoshop & Lightroom & Bridge & Mobile Lightroom