NullableTypes/src/Types NullableDateTime.cs,1.21,1.22

[Damien G. <dam...@us...>]

Update of /cvsroot/nullabletypes/NullableTypes/src/Types
In directory sc8-pr-cvs1.sourceforge.net:/tmp/cvs-serv29576/src/Types

Modified Files:
	NullableDateTime.cs 
Log Message:
Change the behaviour of NullableDateTime.Add to return a new NullableDateTime in line with .Subtract, +, - and DateTime as per issue 1281536.
Also added missing .Add and .Subtract method unit tests.

Index: NullableDateTime.cs
===================================================================
RCS file: /cvsroot/nullabletypes/NullableTypes/src/Types/NullableDateTime.cs,v
retrieving revision 1.21
retrieving revision 1.22
diff -C2 -d -r1.21 -r1.22
*** NullableDateTime.cs	20 Feb 2004 00:42:22 -0000	1.21
--- NullableDateTime.cs	23 Sep 2005 12:06:22 -0000	1.22
***************
*** 27,30 ****
--- 27,32 ----
  //                                   other types in NullableTypes
  // 18-Feb-2004  Luca    Bug Fix      ReadXml must read nil value also with a non empty element
+ // 23-Sep-2005  DamienG Change       Change the .Add method to return a new NullableDateTime structure and not
+ //                                   modify this one, as is consistent with DateTime.
  //
  
***************
*** 436,449 ****
  
          /// <summary>
!         /// Adds a specified time interval to this structure. 
          /// </summary>
          /// <param name="t">A System.TimeSpan</param>
!         public void Add(sys.TimeSpan t) {
!             if (_notNull)
!                 _value += t;
          }
  
          /// <summary>
!         /// Subtracts a specified time interval to this structure. 
          /// </summary>
          /// <param name="t">A System.TimeSpan</param>
--- 438,461 ----
  
          /// <summary>
!         /// Adds a specified time interval to this date and time in this structure
!         /// yielding a new date and time.
          /// </summary>
          /// <param name="t">A System.TimeSpan</param>
!         /// <returns>
!         /// A NullableDateTime that is the sum of this structure and <paramref name="t"/>.
!         /// </returns>
!         /// <remarks>
!         /// This method does not change the value of this NullableDateTime. Instead, a new NullableDateTime
!         ///  is returned whose value is the result of this operation.
!         /// </remarks>
!         public NullableDateTime Add(sys.TimeSpan t) {
!             if (IsNull)
!                 return NullableDateTime.Null;
!             return new NullableDateTime(_value + t);
          }
  
          /// <summary>
!         /// Subtracts a specified time interval from the date and time in this structure
!         /// yielding a new date and time.
          /// </summary>
          /// <param name="t">A System.TimeSpan</param>