message: fix: flaky test when sync metadata
diff: @@ -453,6 +453,7 @@ class TestDatabaseModel(SupersetTestCase):
  # make sure the columns have been mapped properly
  assert len(table.columns) == 4
  + with db.session.no_autoflush:
  table.fetch_metadata(commit=False)
  # assert that the removed column has been dropped and
  @@ -465,15 +466,13 @@ class TestDatabaseModel(SupersetTestCase):
  }
  cols: Dict[str, TableColumn] = {col.column_name: col for col in table.columns}
  # assert that the type for intcol has been updated (asserting CI types)
  - backend = get_example_database().backend
  + backend = table.database.backend
  assert VIRTUAL_TABLE_INT_TYPES[backend].match(cols["intcol"].type)
  # assert that the expression has been replaced with the new physical column
  assert cols["mycase"].expression == ""
  assert VIRTUAL_TABLE_STRING_TYPES[backend].match(cols["mycase"].type)
  assert cols["expr"].expression == "case when 1 then 1 else 0 end"
  - db.session.delete(table)
  -
  @patch("superset.models.core.Database.db_engine_spec", BigQueryEngineSpec)
  def test_labels_expected_on_mutated_query(self):
  query_obj = {
  