Apple recently in the App Store listed “Accessory Developer Assistant” application, used to test whether an accessory is compatible with Apple devices.
Reports suggest that Apple is distributing through Apple Developer Accounts, but they are not yet listed.
The application is described as follows:
"Accessory Developer Assistant is a companion application to the Accessory Developer Guide. It is a comprehensive set of tools designed to help accessory manufacturers test and verify that their new products are as compatible with Apple's devices as expected."
The Apple app page shows testing options for camera hardware, NFC, battery management, case compatibility, and more for iPhone and iPad.