private static void TestPass()
        {
            IDataLayer dal    = CreateDataLayer();
            var        helper = new SampleXpoImportHelper(dal, 100);

            helper.Import(Enumerable.Range(1, 10000));
            Report(dal);
        }
        private static void TestFail()
        {
            IDataLayer dal    = CreateDataLayer();
            var        helper = new SampleXpoImportHelper(dal, 100);

            try {
                helper.Import(Enumerable.Range(1, 10000).Select(x => (x < 1234) ? x : x - 1)); //a duplicated entry
            } catch (Exception ex) {
                Console.WriteLine(ex.GetType().Name);
            }
            Report(dal);
        }