[CMake] Test input files handling

[Gennadiy Rozental]

Hi,

What is the best practice to handle test input files with cmake? Let's say
these files resides in test source subdirectory input. Right now I copy them
into bin directory and execute test from there (by specifying
WORKING_DIRECTORY in add_test), but these files does not really belong
there. What I would prefer is to keep them where they are and just run hte
test somehow letting it know where they are.

Regards,
Gennadiy