public void InsertDeleteTest()
{
var addr = new ExcelAddress("A1:B3");
Assert.AreEqual(addr.AddRow(2, 4).Address, "A1:B7");
Assert.AreEqual(addr.AddColumn(2, 4).Address, "A1:F3");
Assert.AreEqual(addr.DeleteColumn(2, 1).Address, "A1:A3");
Assert.AreEqual(addr.DeleteRow(2, 2).Address, "A1:B1");
Assert.AreEqual(addr.DeleteRow(1, 3), null);
Assert.AreEqual(addr.DeleteColumn(1, 2), null);
}