I've tried the commands from Google
adb shell dumpsys battery unplug
adb shell dumpsys deviceidle step
Stepped to: ACTIVE
adb shell dumpsys deviceidle force-idle
Unable to go idle; not enabled
I'm part of the Genymotion team.
The release note is not correct and our patch for Doze feature has not been released on the preview. Sorry for this mistake.
We will soon release Marshmallow officially and it will include Doze feature. On this future release you will need to enable Doze manually, at each device startup, by running the following command:
adb shell dumpsys deviceidle enable
Then, all the usual commands will work perfectly:
adb shell dumpsys battery unplug adb shell dumpsys deviceidle step
UPDATE: The release has been done, Doze is available now on Genymotion devices.