Fixed JSON availability test. This fixes #77

flask/__init__.py

@@ -17,8 +17,12 @@ from jinja2 import Markup, escape
 
 from flask.app import Flask, Request, Response
 from flask.config import Config
-from flask.helpers import url_for, jsonify, json_available, flash, send_file, \
-    get_flashed_messages, get_template_attribute, json
+from flask.helpers import url_for, jsonify, json_available, flash, \
+    send_file, get_flashed_messages, get_template_attribute
 from flask.globals import current_app, g, request, session, _request_ctx_stack
 from flask.module import Module
 from flask.templating import render_template, render_template_string
+
+# only import json if it's available
+if json_available:
+    from flask.helpers import json