6502 cpu + memory test

Any 6502 architecture runs on pretty old hardware.  Having a reset routine that would completely test all CPU/ROM/RAM would be beneficial to any new applications that run on 6502 architectures.

Let's try to write a routine that can absolutely confirm that as much of the actual 6502 CPU plus any found ROM or RAM is working as is possible.  It'd be more of a challenge than you'd initially think because you cannot use a component such as a register or memory location in the test until you confirm that it works.

Assume this routine exists in ROM and that there is guaranteed to be RAM at $180-$1FF.  Locations of RAM and ROM should ideally be available in a lookup table if this is possible.

>>5
Well, it's more involved than just writing a simple loop that STA's then LDA's from memory.  I want a COMPLETELY ROBUST test, that means:

 - the CPU itself is tested and established as working.
 - the ROM that contains the test is itself tested and established as working as well.
 - the problem of testing the ROM itself - It seems like sort of a chicken and egg problem to me; you can't test RAM or even CPU until you establish that the CPU is working, however, the program that does so is in ROM and therefore you'd have to establish the ROM is working beforehand.

I would like to write something that tests and logically verifies as much as possible, even though some stuff will have to be assumed, etc.

Furthermore I want to test for addressing errors as well, so it's a bit more involved.