If we can generate a testable MSI file that would be the best. Including a very small pre-generated MSI for the purposes of the test would be acceptable.
As-is, the tests don't pass because my machine has C:\Windows\installer\1032f.msi that gets used for the test, which apparently doesn't work with this functionality, and other machines may end up with the same situation. I'm not sure if that's a bug in the code or in whatever MSI that is, though. The OpenDatabase call returns "unknown error 6e" for both new tests.