used iPhone app testing -basics

Question

I've seen parts of this question asked a few time, but I have specific questions that I can't find an answer to.

I have written a simple iPhone app, and would like to test it on my own device. However, I don't currently own a device so am in the market for a used iPhone (3GS) or iPod touch (4thGen).

If I go for the iPhone (my preferred option) does it matter if i) it has no contract? ii) it is locked to AT&T or unlocked?

Can you restore/upgrade a non-contracted phone to iOS 6 through iTunes?

Finally, iPhone GPS is my main reason for preferring it over the iPod touch. Does this still work on a non-contracted phone i.e. does it work with wireless?

As I have never owned a smart phone, I apologise if these questions seem a bit dumb. Thanks for the help

EDIT: My question is a little vague so to clarify the two main points are i) Can you test apps on a 'out of contract' iPhone with no SIM? ii) Without 3G, does an iPhone 'estimate' GPS location using wireless or will the GPS api return an error message (I think this is answered by Benmj)?

Answer 1

There are a couple of questions in here, but it seems like the main one is "can I test my application on an iPhone without a contract?"

Yes. Yes you can. This will be just like developing for an iPod. I have an iPhone and recently severed the contract. I still use it for development.

In terms of GPS: you will only be able to test this if you have a phone contract. The GPS works based on the cell phone towers. You might be able to have limited location awareness based on which wireless network you connect to (similar to how desktop browsers can now have some limited geographic awareness), but if you want to get GPS locations, calculate distances, etc, you will need to have a wireless plan.