Create a Shopify test store and test your integration with it.
Log in/Create your Shopify account on Shopify Partners.
Click on “Add store” -> “Create development store”
Select the “Create a store to test and build” option and fill out the details.
Now to add your own product:
Now to set up test payments:
In Payments Enable Shopify Payments by clicking “Switch to Shopify Payments” -> “Activate Shopify Payment”
Fill in the required information in order to enable Shopify Payments.
Enable Test Mode for Shopify Payments
Publish your Shopify store to remove the password and test the API