def test_pluginDirectories(self):
        """
        L{plugin.pluginPackagePaths} should return a list containing each
        directory in C{sys.path} with a suffix based on the supplied package
        name.
        """
        foo = FilePath('foo')
        bar = FilePath('bar')
        sys.path = [foo.path, bar.path]
        self.assertEqual(
            plugin.pluginPackagePaths('dummy.plugins'),
            [foo.child('dummy').child('plugins').path,
             bar.child('dummy').child('plugins').path])

        L{plugin.pluginPackagePaths} should return a list containing each
        directory in C{sys.path} with a suffix based on the supplied package
        name.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_plugin.py