@Test
  public void delete_tables() throws SQLException {
    underTest.execute();

    db.assertTableDoesNotExist("widget_properties");
    db.assertTableDoesNotExist("widgets");
    db.assertTableDoesNotExist("active_dashboards");
    db.assertTableDoesNotExist("dashboards");
  }
  @Test
  public void migration_is_re_entrant() throws Exception {
    underTest.execute();
    underTest.execute();

    db.assertTableDoesNotExist("widget_properties");
    db.assertTableDoesNotExist("widgets");
    db.assertTableDoesNotExist("active_dashboards");
    db.assertTableDoesNotExist("dashboards");
  }