Service Connect doesn't have an obvious way to develop test Workflows and publish to a production with a single instance. If you had multiple you might use the backup/restore.
So far the best way I have found is to have 2 Workflow Packages of Workflows, one test one live. Each using separate .net assemblies clearly marked as test or live. Delete the workflows in the package you want to replace. "Move" the workflows from the source package, but to copy them, uncheck the box that says remove them. Then use the Workflow packages > Update Processes context menu action and remap the assemblies.
This almost does it however, because of the way I do Posters, I have to go in and adjust all posters that have email addresses set or hard coded subjects indicating live or test. That's probably just a design flaw in my design that can be fixed.
However, if you use sub workflows in any of the items you copied, you need to manually repoint them, they are pointing to the Workflows in the other environment and yes... they will run that way! Also if you have anything Test vs Live dependent in Process Variables... manually deal with those.
Another thing that is frustrating is if User Schemas need to be changed, there is no good answer with test and live versions of these. I have been using generic for both and have usually only needed to add a field so there is no consequence. But it seems like a potential hell.
I think I get lucky because I use very limited feature set of Service Connect or there would be even more hell.