You can run the unit tests with the following command:
$ ./run_tests.sh -f -V
run_tests.sh installs its requirements to .venv on the initial run. -f forces a clean re-build of the virtual environment. If you just make changes on the working tree without any change on the dependencies, you can ignore -f switch.
-V or --virtual-env is specified to use virtualenv and this should be always turned on.
To know more detail about command options, please execute it with --help:
$ ./run_tests.sh --help