Use parallel jobs in ctest

[boxerab]

Running ctest with the option -j allows it to run tests in parallel. For example,

ctest -j 8

will run with 8 threads. On my quad core machine, this setting cut the time to run ctest in half.
As the test suite is growing ( a good thing), it is very helpful to shorten the test cycle.

So, it would be great to put this setting in the cmake files, somehow.

I tried setting

set(CTEST_PARALLEL_LEVEL 8)

in CTestCustom.cmake.in

but this didn't change the command line options.

[boxerab]

CTEST_PARALLEL_LEVEL is an environment variable. On windows, it is not possible via cmake to add this command line option to the post-build step in visual studio. One solution is to set a windows environment variable named CTEST_PARALLEL_LEVEL, with value set to 8, for example. This will tell ctest to spawn 8 jobs when running the test suite.