Hi there, @waxglass2020.

You can create a sales receipt and enter it with a zero amount to check if the product testing is deducting from your inventory. Please follow these steps on how to create a sales receipt:

1. Go to the Customers menu.
2. Select Enter Sales Receipt.
3. Choose the customer in the field.
4. Select either Cash, Check, Credit/Debit, E-Check, or more.
5. Fill out the necessary fields needed.
6. Enter a zero amount in the Amount column.
7. Click Save and Close.

In case you need help tracking an inventory in multi-location in tracking inventory, you can read this article for more detailed information: Multiple Inventory Sites.

Please know that I'm always around here in the Community to help. Take care, and have a wonderful day!