public void IsValidColumnTest()
{
Assert.AreEqual(false, XLHelper.IsValidColumn(""));
Assert.AreEqual(false, XLHelper.IsValidColumn("1"));
Assert.AreEqual(false, XLHelper.IsValidColumn("A1"));
Assert.AreEqual(false, XLHelper.IsValidColumn("AA1"));
Assert.AreEqual(true, XLHelper.IsValidColumn("A"));
Assert.AreEqual(true, XLHelper.IsValidColumn("AA"));
Assert.AreEqual(true, XLHelper.IsValidColumn("AAA"));
Assert.AreEqual(true, XLHelper.IsValidColumn("Z"));
Assert.AreEqual(true, XLHelper.IsValidColumn("ZZ"));
Assert.AreEqual(true, XLHelper.IsValidColumn("XFD"));
Assert.AreEqual(false, XLHelper.IsValidColumn("ZAA"));
Assert.AreEqual(false, XLHelper.IsValidColumn("XZA"));
Assert.AreEqual(false, XLHelper.IsValidColumn("XFZ"));
}