Part-I: Simple Addition of Two Number Using WPF MVVM Pattern Part-II: Unit testing for same Application Part-I: Simple Addition of Two Number Using WPF MVVM Pattern Folder Structure(Part-I) Folder: Model - > AdditionofNumbers.cs public class AdditionofNumbers : PropertychangeNotify { private int num1; public int NUM1 { get { return num1; } set { num1 = value ; Notifypropertychange( "NUM1" ); } } private int num2; public int NUM2 { get { return num2; } set { num2 = value ; Notifypropertychange( "NUM2" ); } } private int addresult; public int ADDRESULT { get { return addresult; } set { addresult = value ; Notifypropertychange( "ADDRESULT" ); } } } Folder: ViewMode