FindCxxTest runs incorrect python executable
On Fedora 24+, cxxtestgen is a python3 executable with a #!/usr/bin/python3 shbang. However, FindCxxTest calls it with /usr/bin/python, which fails. See http://public.kitware.com/pipermail/cmake/2016-August/064027.html for more.
There is no need to call with python explicitly on Linux/Unix. Not sure what the situation on Windows is.