old_contents: import mangler
  config = {
          'log_level': 'DEBUG',
          'twanager.tracebacks': True,
          'twanager_plugins': ['tiddlywebplugins.migrate'],
          'server_store': ['tiddlywebplugins.sqlalchemy', {
              'db_config': 'sqlite:///migrate.db'}],
          }
  
new_contents: import mangler
  config = {
          'log_level': 'DEBUG',
          'twanager.tracebacks': True,
          'server_store': ['tiddlywebplugins.sqlalchemy', {
              'db_config': 'sqlite:///test.db'}],
          }
  
subject: Use correct test database.