Wow, gotta say, it took longer than I think it should have for Ning to deliver Test Networks. But, good news is: it's been delivered! The test Network feature is for Ning Plus and Ning Pro Plans.

See original announcement/discussion on the Ning Creator Site, here:
http://creators.ning.com/forum/topics/new-feature-for-ning-plus-pro

The Test Network Feature provides a sandbox type environment, directly accessible from within your live Ning Network. Yet it provides a completely separate testing environment. This will enable you to test design changes or custom code before you publish them live, for your members and site visitors to see.

To access your Test Environment, go to:

My Network/Tools/Test Network

---

Original announcement by Junaid Basir of Team Ning:

The first time you visit this page, it will show you a "Create Test Network" link. Clicking this link will create your test network, which will automatically open in a new
browser window. That’s all you need to do to get started.

Your test network will always be private, so you will be asked to sign in. At creation time, your test network is set up with the same email address and password as your live Ning Network. If you
wish, you can change the password. Once signed in, you can safely try
out changes in this separate test environment. Your test network will
always have a visual call out — a persistent banner at the top of your
test network — so you’ll always be able to quickly distinguish your live
network from your test network.

When your test network is first created, key settings from your live network will be replicated, including your Main Page layout, Text Boxes, and RSS Feeds. Also included will be Feature settings and
preferences, Theme, Advanced CSS, Custom Code, Language Editor settings,
and the File Manager (Ning Pro only). Note that most content,
such as Blogs, Forum discussions, Photos, Videos, Events, and Groups
will not be replicated. For full details on the settings, check
out this Help Center article.

Want to get other people involved? You can invite up to ten members to your test network. For example, you could invite trusted Admins to provide feedback on potential changes to your live network.

If you’ve made a lot of changes to your test network and need to reset your test network, you can. We’ve added a “Copy Settings” function that allows you to easily reset your test network to reflect the
current settings of your live network.

We hope this new feature will help you feel confident in exploring new ideas and choices in a safe environment!

---

---------------------------- End Announcement from Ning  ------------------------------

Happy Testing!
Jen