try-pip-main-install-nested-package.py

#!/usr/bin/env python2

## !!! WARNING: THIS CODE COULD VERY WELL REMOVE YOUR SYSTEM-WIDE
## plaitpy AND bda.basen PACKAGES !!!

# verify that we start with a clean slate: no plaitpy, no bda.basen
import os
assert not os.path.isfile('/usr/local/lib/python2.7/dist-packages/plaitpy/__init__.py')
try:
        import plaitpy # this fails, as expected
        assert False
except: pass
assert not os.path.isfile('/usr/local/lib/python2.7/dist-packages/bda/basen/__init__.py')
try:
        import bda.basen # this fails, as expected
        assert False
except: pass

try:
#=======================================================================================

        import sys
        import os

        # The following code successfully installs bda.basen, then fails to import it.
        # However, it works for plaitpy (a random recently updated package).

        assert '/usr/local/lib/python2.7/dist-packages' in sys.path

        import pip
        pip.main(['install', 'plaitpy', 'bda.basen'])

        assert '/usr/local/lib/python2.7/dist-packages' in sys.path

        assert os.path.isfile('/usr/local/lib/python2.7/dist-packages/plaitpy/__init__.py')
        import plaitpy # this succeeds, as expected
        print plaitpy

        assert os.path.isfile('/usr/local/lib/python2.7/dist-packages/bda/basen/__init__.py')
        import bda.basen # THIS FAILS WITH 'ImportError: No module named bda.basen'
        print bda.basen

#=======================================================================================
finally:
        # go back to our clean slate
        print '--------------'
        print 'BEGIN CLEAN-UP'
        try:
                import pip
                pip.main(['uninstall', '-y', 'bda.basen'])
                pip.main(['uninstall', '-y', 'plaitpy'])
        finally:
                print 'END CLEAN-UP'
                print '------------'