Listado() public method

public Listado ( string Campos, string Condicion, string Orden ) : DataTable
Campos string
Condicion string
Orden string
return System.Data.DataTable
        protected void Page_Load(object sender, EventArgs e)
        {
            if (!IsPostBack)
            {
                Egresos egreso = new Egresos();

                EgresosReportViewer.ProcessingMode = Microsoft.Reporting.WebForms.ProcessingMode.Local;
                EgresosReportViewer.Reset();
                EgresosReportViewer.LocalReport.ReportPath = Server.MapPath(@"~\Rpts/EgresosRpt.rdlc");

                EgresosReportViewer.LocalReport.DataSources.Clear();

                EgresosReportViewer.LocalReport.DataSources.Add(new Microsoft.Reporting.WebForms.ReportDataSource("EgresosDataSet", egreso.Listado(" * ", "1=1", "")));
                EgresosReportViewer.LocalReport.Refresh();
            }
        }
        protected void ConsultaBuscarButton_Click(object sender, EventArgs e)
        {
            Egresos egreso = new Egresos();
            DataTable dataTable = new DataTable();
            string condicion;

            if (DatosTextBox.Text.Trim().Length == 0)
            {
                condicion = "1=1";
            }
            else
            {
                condicion = ElementosDropDownList.SelectedItem.Text + " = " + DatosTextBox.Text;
            }
            dataTable = egreso.Listado(" * ", condicion, "");
            ElementosGridView.DataSource = dataTable;
            ElementosGridView.DataBind();
        }
 public void ListadoTest()
 {
     Egresos egreso = new Egresos();
     Assert.IsTrue(egreso.Listado(" * ", "1=1", "").Rows.Count > 0);
 }