import os
import shutil
import sys
import tempfile
import unittest


class NestedNamespacePackage(unittest.TestCase):

    def setUp(self):
        self.basedir = tempfile.mkdtemp()
        self.old_path = sys.path[:]

    def tearDown(self):
        sys.path[:] = self.old_path
        shutil.rmtree(self.basedir)

    def create_module(self, name, contents):
        base, final = name.rsplit('.', 1)
        base_path = os.path.join(self.basedir, base.replace('.', os.path.sep))
        os.makedirs(base_path, exist_ok=True)
        with open(os.path.join(base_path, final + ".py"), 'w') as f:
            f.write(contents)

    def test_nested(self):
        pkgutil_boilerplate = (
            'import pkgutil; '
            '__path__ = pkgutil.extend_path(__path__, __name__)')
        self.create_module('a.pkg.__init__', pkgutil_boilerplate)
        self.create_module('b.pkg.__init__', pkgutil_boilerplate)
        self.create_module('a.pkg.subpkg.__init__', pkgutil_boilerplate)
        self.create_module('b.pkg.subpkg.__init__', pkgutil_boilerplate)
        sys.path.insert(0, os.path.join(self.basedir, 'a'))
        sys.path.insert(0, os.path.join(self.basedir, 'b'))
        import pkg
        self.assertEqual(len(pkg.__path__), 2)
        import pkg.subpkg
        self.assertEqual(len(pkg.subpkg.__path__), 2)


if __name__ == "__main__":
    unittest.main()