code: public static void assertUnchanged(String message, DataSource dataSource) throws DBAssertionError {
      DataSet emptyDataSet = empty(dataSource);
      DBAssert.deltaAssertion(CallInfo.create(message), emptyDataSet, emptyDataSet);
    }
docs: Assert that no changes occurred for the given data source
  (error message variant).
  
  @param message Assertion error message.
  @param dataSource Data source.
  @throws DBAssertionError if the assertion fails.
  @see #assertDelta(DataSet,DataSet)
  @see #assertDeleted(String, DataSet)
  @see #assertInserted(String, DataSet)