Yes. I'll file a follow-up. Here's the tricky bit: SQLite does not really support changing column types; one must do a little new-copy-delete-rename dance. Django-south does this automatically I think, but it seems that sqlalchemy+alembic does not. Currently the tests are run with PostgreSQL and SQLite, so tests that trigger this limitation were simplified. The two Right Ways to do it would be to fix alembic (or figure out if maybe it is fixed in some way already) or to have some tests run on all databases except SQLite.