Change in flashrom[master]: tests: Add NON_ZERO macro and not_null function instead of MOCK_HANDLE

[Nico Huber (Code Review)]

Attention is currently required from: Edward O'Callaghan, Angel Pons, Anastasia Klimchuk.
Nico Huber has posted comments on this change. ( https://review.coreboot.org/c/flashrom/+/57269 )

Change subject: tests: Add NON_ZERO macro and not_null function instead of MOCK_HANDLE
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Patch Set 4: Code-Review+1

(2 comments)

Patchset:

PS4: 
I wonder if `io_mock` is the right place for it. not_null() doesn't
have to be about I/O, does it? There's an `include/test.h`, maybe
that would be a better place?

File tests/io_mock.h:

https://review.coreboot.org/c/flashrom/+/57269/comment/14368fb4_cebb69c7 
PS1, Line 38:  NOT_NULL ((void *)NOT_ZERO)
> I created not_null() function, but left NON_ZERO as macro, is this what you meant, or you meant them […]

Edward, is this what you had in mind?