---
features:
  - |
    Introduced neutron_lib.fixture, and added fixture for plugin
    directory ``PluginDirectoryFixture``. An example below:

    .. code-block:: python

        from neutron_lib.plugins import directory
        from neutron_lib import fixture


        def setup_test_directory_instance(self):
            """Give a private copy of the directory to each test."""
            self._plugin_directory = directory._PluginDirectory()
            self.useFixture(fixture.PluginDirectoryFixture(
                plugin_directory=self._plugin_directory))
