public void AddNode_NullObjects_ShouldWork()
{
// Arrange
using (var workbook = this.ExcelApplication.Workbooks.Add())
{
CustomXMLPart cxp1 = workbook.CustomXMLParts.Add("<invoice />");
CustomXMLNode cxn = cxp1.SelectSingleNode("/invoice");
// Act
Assert.Throws <MethodCOMException>(() => cxp1.AddNode(cxn, null, null, null, null, null));
// Assert
// Assert.AreEqual(@"<invoice><upccode xmlns=""urn: invoice:namespace""/></invoice>", cxp1.XML);
}
}