How to use the rocker.cli.list_plugins function in rocker

def test_env_extension(self):
        plugins = list_plugins()
        env_plugin = plugins['env']
        self.assertEqual(env_plugin.get_name(), 'env')

        p = env_plugin()
        self.assertTrue(plugin_load_parser_correctly(env_plugin))
        
        mock_cliargs = {'env': [['ENVVARNAME=envvar_value', 'ENV2=val2'], ['ENV3=val3']]}

        self.assertEqual(p.get_snippet(mock_cliargs), '')
        self.assertEqual(p.get_preamble(mock_cliargs), '')
        self.assertEqual(p.get_docker_args(mock_cliargs), ' -e ENVVARNAME=envvar_value -e ENV2=val2 -e ENV3=val3')

def test_user_extension(self):
        plugins = list_plugins()
        user_plugin = plugins['user']
        self.assertEqual(user_plugin.get_name(), 'user')

        p = user_plugin()
        self.assertTrue(plugin_load_parser_correctly(user_plugin))

        env_subs = p.get_environment_subs()
        self.assertEqual(env_subs['gid'], os.getgid())
        self.assertEqual(env_subs['uid'], os.getuid())
        self.assertEqual(env_subs['name'],  getpass.getuser())
        self.assertEqual(env_subs['dir'],  str(Path.home()))
        self.assertEqual(env_subs['gecos'],  pwd.getpwuid(os.getuid()).pw_gecos)
        self.assertEqual(env_subs['shell'],  pwd.getpwuid(os.getuid()).pw_shell)

        mock_cliargs = {}
        snippet = p.get_snippet(mock_cliargs).splitlines()

def test_return_code_multiple_extensions(self):
        plugins = list_plugins()
        desired_plugins = ['home', 'user']
        active_extensions = [e() for e in plugins.values() if e.get_name() in desired_plugins]
        dig = DockerImageGenerator(active_extensions, {}, 'ubuntu:bionic')
        self.assertEqual(dig.build(), 0)
        self.assertEqual(dig.run('true'), 0)
        self.assertEqual(dig.run('false'), 1)

def test_list_plugins(self):
        plugins_found = list_plugins()
        plugin_names = plugins_found.keys()
        self.assertTrue('nvidia' in plugin_names )
        self.assertTrue('pulse' in plugin_names )
        self.assertTrue('user' in plugin_names )
        self.assertTrue('home' in plugin_names )

def test_pulse_extension(self):
        plugins = list_plugins()
        pulse_plugin = plugins['pulse']
        self.assertEqual(pulse_plugin.get_name(), 'pulse')

        p = pulse_plugin()
        self.assertTrue(plugin_load_parser_correctly(pulse_plugin))
        
        mock_cliargs = {}
        snippet = p.get_snippet(mock_cliargs)
        #first line
        self.assertIn('RUN mkdir -p /etc/pulse', snippet)
        self.assertIn('default-server = unix:/run/user/', snippet) #skipping user id that's system dependent
        self.assertIn('autospawn = no', snippet)
        self.assertIn('daemon-binary = /bin/true', snippet)
        #last line
        self.assertIn('> /etc/pulse/client.conf', snippet)
        self.assertEqual(p.get_preamble(mock_cliargs), '')

def test_home_extension(self):
        plugins = list_plugins()
        home_plugin = plugins['home']
        self.assertEqual(home_plugin.get_name(), 'home')

        p = home_plugin()
        self.assertTrue(plugin_load_parser_correctly(home_plugin))
        
        mock_cliargs = {}
        self.assertEqual(p.get_snippet(mock_cliargs), '')
        self.assertEqual(p.get_preamble(mock_cliargs), '')
        args = p.get_docker_args(mock_cliargs)
        self.assertTrue('-v %s:%s' % (Path.home(), Path.home()) in args)