Execute custom command inside setup.py's sandbox

setup.py

class TestMappingsCommand(distutils.cmd.Command):
    user_options = []

    def initialize_options(self):
        pass

    def finalize_options(self):
        pass

    def run(self):
        # installs everything in install_requires (in setup.py) in a sandbox
        self.distribution.fetch_build_eggs(self.distribution.install_requires)
        # runs another command within the sandbox
        self.run_command('compile_confugration_resources')
        # executes a script within the sandbox
        imp.load_source('compare_mappings', "scripts/compare-mappings.py").main()