Split testing the automation into two parts: testing the trigger and testing the actions.
Test the trigger with an action that doesn’t send anything to the client. If the trigger is simple enough, you can skip this part.
Test the actions with a different trigger, such as a special check box field so that you can select a test client.
Then change the trigger to match the proper trigger. Note that you do not actually have to test the trigger again in order to turn it on.