def _walk_versions(self, snake_walk=False, downgrade=True):
# Determine latest version script from the repo, then
# upgrade from 1 through to the latest, with no data
# in the databases. This just checks that the schema itself
# upgrades successfully.
# Place the database under version control
alembic_cfg = migration._alembic_config()
script_directory = script.ScriptDirectory.from_config(alembic_cfg)
self.assertIsNone(self.migration_api.version())
versions = [ver for ver in script_directory.walk_revisions()]
LOG.debug('latest version is %s', versions[0].revision)
for version in reversed(versions):
self._migrate_up(version.revision, with_data=True)
if snake_walk:
downgraded = self._migrate_down(
version, with_data=True)
if downgraded:
self._migrate_up(version.revision)
if downgrade:
for version in versions:
downgraded = self._migrate_down(version)
if snake_walk and downgraded:
self._migrate_up(version.revision)
self._migrate_down(version)
def test_single_branch(self):
alembic_cfg = migration._alembic_config()
script_directory = script.ScriptDirectory.from_config(alembic_cfg)
actual_result = script_directory.get_heads()
self.assertEqual(1, len(actual_result),
"Db migrations should have only one branch.")
