When testing using Flash CC 2014, I get an error Functions called in incorrect sequence, or earlier call was unsuccessful.
Does this feature require the actual iOS or Android device to test, or can it be tested without it?
No, you can also test it using the iOS Simulator as well and possibly the Android Simulator, if you can get that working (I never bother with the Android simulator, though, even when working with native development). You cannot test it using the AIR Simulator, though. The camera functionality requires native APIs to function.
Also, keep in mind that the CameraRoll (and camera functionality in general) varies by platform. Do not assume that because you tested it on an Android device, it will work properly on an iOS device or vice versa. You must test it on all supported platforms.