The test suite operated solely on schema changes, without any data in

the database for those models. This meant that the tests missed some

important things. For instance, on SQLite, Django Evolution 2.0

regressed adding non-NULL fields when there's data in a table, and this

wasn't caught in the tests due to the lack of data.
Now every test suite can inject data into the models prior to mutation,

ensuring that we're operating in a more real-world scenario.
This currently breaks the SQLite tests (revealing the aforementioned

bug), but those will be fixed in an upcoming change.

Unit tests pass except on SQLite (where the bug manifests).
Unit tests pass completely with an upcoming fix.