We are awake of the issue that the screensaver is running on the OSX containers and will fix this regression soon with an update to our OSX image.
For now you can mitigate this by simulating a keystroke in your circle.yml configuration file.
machine:
post:
- osascript -e 'tell application "System Events" to keystroke "c"'
If you have tests than run longer than 30 minutes I’d suggest that you run the command in between test steps again.
Thank you for your patience,
Constantin