Using xcode 4 but targeting OSX Leopard (10.5) and above

I was developing an application using xcode 4 to target snow leopard (10.6) Now, nearly the end of the development, I've been asked to support 10.5+.

I have set the Mac OS deployment target to 10.5 and compiled. The compiler (LLVM 2.0) and linker seems to be happy with the change but I came across a feature I've used from NSWindow (isOnActiveSpace) which is states as AVAILABLE_MAC_OS_X_VERSION_10_6_AND_LATER

This I understand states that it won't work (throw exception?) in 10.5 but no warning were raised when building.

I currently don't have a leopard installation and it will take our QA some time to arrange a computer for that, so in your experience, what should I do next? how can I开发者_如何学JAVA go over the code and make sure that all the APIs I've used are in fact safe for 10.5?

Set MAC_OS_X_VERSION_MAX_ALLOWED to 1050 and see what symbols disappear. More info in TN2064.