Python virtual environment

include(PythonVirtualEnv)

It creates a python virtual environment inside the build tree. The environment can be accessed in CMake scripts via ${LOCAL_PYTHON_EXECUTABLE}, and within the shell via the localpython.sh scripts. All arguments to this script are passed on to python.

The script is setup to read from a pypaths (ldpaths) file and add each line to the PYTHONPATH (LD_LIBRARY_PATH and DYLD_LIBRARY_PATH) environment variable. Thus is is possible to setup the script to know about python modules (shared libraries) located within the build tree.

add_to_python_path("path/to/module/directory/in/build/tree")
add_to_ld_path("path/to/shared/library/directory/in/build/tree")

The two functions above make it easier to add paths to the relevant files directly from CMake.

Finally, a function is provided to install packages within the virtual environment:

add_package_to_virtualenv(pytest)

It will use pip to do the actual work.