public void Item()
{
var ds = new DataSet();
DataTable dt = new DataTable("NewTable1");
DataTable dt1 = new DataTable("NewTable2");
ds.Tables.AddRange(new DataTable[] { dt, dt1 });
Assert.Equal(dt, ds.Tables[0]);
Assert.Equal(dt1, ds.Tables[1]);
Assert.Equal(dt, ds.Tables["NewTable1"]);
Assert.Equal(dt1, ds.Tables["NewTable2"]);
}