code: def test_api_prefix(self, app):
      api = restplus.Api(app, prefix="/foo")
      assert api.prefix == "/foo"
  
imports: from __future__ import unicode_literals
  import flask
  import pytest
  import six
  from json import dumps, JSONEncoder
  from flask import Blueprint, redirect, views
  from werkzeug.exceptions import HTTPException, Unauthorized, BadRequest
  import flask_restplus
label_desc: Use image node_id 11 for calling the APITest obj's underlying member method code with example usage: obj.test_api_prefix(app) without return types