How much unit test coverage you need?

Not less than 80% of coverage is advisable.

Effective test should consider not only code, but also input parameters, and application state which could also affect the behavior.

1. test success condition
2. test failure condition
3. test boundary condition

http://www.codeproject.com/KB/testing/UnitTestVS2008.aspx

Sealed

• It restricts inheritance
• Cannot derive from Sealed type

 

Const vs ReadOnly in .net

Const

• It is also called as "Compile time constant"
• Const can be assigned at variable initialization
• Once assigned value cannot be changed

ReadOnly

• "Runtime constant"
• ReadOnly field can be assigned at variable initialization and in constructor
• Value can be changed in constuctor

Sample

    class ReadonlyConstant
    {
        private const int x=10;     //compile time constant
        private readonly int y=20;  //runtime constant

        public ReadonlyConstant()
        {
            Console.WriteLine("\n***Const Vs ReadOnly***");
            Console.WriteLine("Const x before initialization=" + x);
            Console.WriteLine("ReadOnly y before initialization=" + y);



            //The left-hand side of an assignment must be a variable, property or indexer
            //x = 20;   // value cannot be changed in constructor

            y = 110;    // value can be changed in constructor   

            Console.WriteLine("Const x after initialization=" + x);
            Console.WriteLine("ReadOnly y after initialization=" + y);
        }

        //public int IncrementY
        //{
        //    //A readonly field cannot be assigned to (except in a constructor or a variable initializer)
        //     set { y++; }
        //}
    }

simple .net singleton pattern

    public sealed class dotnetSingleton
    {
        public static readonly dotnetSingleton Instance = new dotnetSingleton();
        private dotnetSingleton()
        {
        }
    }

Reference: http://msdn.microsoft.com/en-us/library/ee817670.aspx