How do Developers Test upgrades?

So we develop a plugin, but we find it very difficult to test our upgrades? We can simply uninstall and delete plugins on our testing wordpress servers and install new ones, but that does not simulate what users experience in an upgrade with things such as db modifications from one version to the next, etc. Makes it difficult to simulate it and test it thoroughly before we release updates.

Do you have any recommendations, or how do other plugin developers handle this efficiently?