EnumerationExtensions

Here is an extension that helps with bitwise operations on (flagged) enums.

[Flags]

public enum Positions

{

None = 0,
   Left = 1,
   Right = 2,
   Top = 4,
   Bottom = 8,}

public static class EnumerationExtensions

{
    public static T Append<T>(this Enum type, T value)

        {
            return (T)(object)(((int)(object)type | (int)(object)value));
        }

        public static T Remove<T>(this Enum type, T value)

        {
            return (T)(object)(((int)(object)type & ~(int)(object)value));
        }

        public static bool Contains<T>(this Enum type, T value)

        {
            return (((int)(object)type & (int)(object)value) == (int)(object)value);
        }

        public static bool ContainsAny<T>(this Enum type, T value)

        {
            return (((int)(object)type & (int)(object)value) != 0);
        }

        public static bool ContainsNot<T>(this Enum type, T value)

        {
            return !Contains(type, value);
        }

        public static bool Is<T>(this Enum type, T value)

        {
            return (((int)(object)type == (int)(object)value));
        }
    }

then you'll be able to write tests like this :

Positions twoPositions = Positions.Left | Position.Top;

Console.WriteLine(twoPositions.Contains(Position.Top)) // true

Positions position = Positions.None;

position.Append(Position.Bottom);

Console.WriteLine(position.Is(Position.Bottom)); // true (None is overwritten)