Run all tests defined in the CMake project, executing 4 jobs at a time in parallel

CMake test driver program.
More information: <https://gitlab.kitware.com/cmake/community/wikis/doc/ctest/Testing-With-CTest>.
Trick copyright: tl;dr; <https://github.com/tldr-pages/tldr>

ctest -j{{4}} --output-on-failure

click the source code to copy install ctest on any operating system with command-not-found.com