I found the article below. In my situation, however, I am not refreshing the entire farm. I have one web app with some associated workflows. I don't want to overwrite the entire Nintex db in test (since I have other workflows in use there). And my prod farm continues in active use, so I don't want to stop any services or break any connections. My goal is to copy over the SharePoint web app and associated workflows to test.
It isn't so much of a big deal if some workflows are in an odd state after moving. I just want the data and history there, and to be able to restart workflows once moved.
What is the best approach?