Step 1:
Go to the Notification panel, select your integration
Step 2:
Click the 「Enable Testing button」 at the right hand side and key the number you would like to send a test to, after that click「Save」
Note: All notification will be sent to the number that you have setup in the enable testing mode.
Step 3:
Once you have finish testing, disable the 「Enable Testing」 button and click save