Koos van Strien discusses warehouse testing:
Case: we’ve integrated two sources of customers. We want to add a third source.
Q: How do we at the same time know that our current integration and solutions will continue to work while at the same time integrating the new sources?
A: Test it.
Q: How do we get faster deployments and more stability?
A: Automate the tests, so they can run continuously.
This is an interesting concept; do read the whole thing.