Is there any way top specify IAPs with downloads so that I can test that part of my code in Xcode? When I specify a Configuration.storekit and test the IAP flow, the SKPaymentTransaction.downloads is (obviously enough) empty...
Testing StoreKit IAPs with downloads in Xcode
SKDownload is not a supported API with StoreKit Testing in Xcode 12. You can use the Sandbox environment to test downloads.
For more on the differences between Xcode and Sandbox environments, check out Testing at All Stages of Development with Xcode and Sandbox.
For more on the differences between Xcode and Sandbox environments, check out Testing at All Stages of Development with Xcode and Sandbox.