Our team is in an annoying situation: Our corporation is in a period of transition that will probably last another 3 to 6 months after a merger between two companies with very different philosophies. The transition is heading in the right direction (the acquired company was acquired for their ability to manage the technical side of things well), but progress is slow and rocky.
Due to politics, re-orgs, and chaos, our PM isn't able to get good specs for us before we start developing an iteration, yet we can't grind to a halt. The developers are able to make do, but I can't co-develop automated tests without a clear idea of the product to work from. Right now basic things like frequent communication between test and business owners doesn't exist, and the design isn't fixed until coding is done. As the tester, I've been scrambling to gather requirements - often from the dev - and change and re-change my fixtures - and it's just not working. Since I'm so busy responding to basic design changes, I don't have time to get much test coverage and I can't follow through on my test plans.
We're looking at starting a two-iteration scrum-fall model for the next 3 to 4 months, where the test / debug work lags one iteration behind the design and development work. Devs will be designing and developing the current iteration of work while I write fixtures for the last iteration, then I'll test their last iteration and they'll fix those bugs. The idea is that this will last for a few months, and then we should have good design docs available.
Things I've thought about already: The "catch-up" iteration, where I'm testing for the previous iteration and the current at once to move to Scrum proper, won't be an issue; I'll halt development on test tools for the iteration, as that normally takes about 50% of my time. We don't have deadline pressure; this is a large, time-consuming project with probably 5 more months before we can go into production (although moving deadlines / resourcing commitments are part of the chaos right now). I trust my PM to work at getting us to the point where we can move back to normal sprints; I don't think a temporary move to scrum-fall will end up being permanent due to laziness.
TL;DR: Due to an inability to get good specs and business requirements early in the sprint, we're going to try having test lag one sprint behind development.
Question: Has anyone been-there, done-that? What pitfalls should I be looking out for, and what can I do to help make this "scrum-fall" system work smoother? What can I do to help the transition back to normal Scrum happen sooner (to pave the road for better documentation and communication)?