The foundation for all push notification campaigns, whether it's automated campaigns or experiments is a simple static push notification itself.
If you don't have that set up properly, you won't be able to send any push notification of any type at all.
In order to have push notifications working properly, you'll need to check out the docs in order to make sure that ALL STEPS have been covered.
Once you have your bases covered, you should start testing on your dev environment to see if you receive pushes on your device.
You can verify if push notifications are being registered (that pop up that asks you whether or not you want to receive push notifications) on devices in User Insights. It won't be instantaneous, so giving User Insights around 10 minutes or so to pick up
Upon clicking on a user you would see this screen:
Click on the "more" button and it reveal more info involving push tokens as seen below:
Upon checking out user insights, you can see if push tokens are being distributed. In the example above, push tokens are not being distributed so that particular user would not get pushes at all if it he/she had a dev or production build.
If Push Tokens are present, whether you're distributing to dev devices or production devices, you should be good to go in terms of testing out pushes in both environments by following the Push Notification Guide here.