To test Stripe gateway and debug the payment system before going into production, enable the option Enable test mode.
You can also activate the log procedure so that all the actions performed by the plugin with test orders are recorded. The path of the log file shows under the Debug Log option. Administrators can consult the recorded logs even from their account, without activating this option.
By normal usage, you should never see a warning, but if you create a staging installation or clone your production site, the Test Mode will be activated and a warning will show. This will protect both you and your customer.