def METHOD_NAME(self):
    app = path_prefix.PathPrefixMiddleware(self._echo_app, "/pfx")
    server = werkzeug_test.Client(app, werkzeug.wrappers.Response)
    with self.subTest("at root"):
        response = server.get("/pfx")
        self._assert_ok(response, path="", script="/pfx")
    with self.subTest("at root with slash"):
        response = server.get("/pfx/")
        self._assert_ok(response, path="/", script="/pfx")
    with self.subTest("at subpath"):
        response = server.get("/pfx/foo/bar")
        self._assert_ok(response, path="/foo/bar", script="/pfx")
    with self.subTest("at non-path-component extension"):
        with self.assertRaises(errors.NotFoundError):
            server.get("/pfxz")
    with self.subTest("above path prefix"):
        with self.assertRaises(errors.NotFoundError):
            server.get("/hmm")