The example tests in Step3 of the CMake tutorial suggest to use the following regexp to verify the output of an executable call.
do_test(Tutorial -25 “-25 is [-nan|nan|0]”)
I think this does not what was intended. That matches a single character which is anything until n, or a, or n, etc.
I guess what the documentation writer intended was to write:
do_test(Tutorial -25 “-25 is (-nan|nan|0)”)
with parentheses. This matches -nan, nan or 0.