def METHOD_NAME(self, walk):
    self.project.set_property("dir_source_main_python",
                              "src/main/python/")
    init_python_directories(self.project)
    src_path = self.project.expand_path("$dir_source_main_python")
    walk.return_value = [
        (join(src_path, "pybuilder"), ["pluginhelper", "plugins"], ("__init__.py", "foo.py", "foo.txt")),
        (join(src_path, "pybuilder", "pluginhelper"), [], ["__init__.py"]),
        (join(src_path, "pybuilder", "plugins"), [], ["__init__.py"])
    ]
    self.assertEqual(
        ["pybuilder",
         "pybuilder.pluginhelper",
         "pybuilder.plugins"],
        self.greedy(self.project.list_packages())
    )