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

        public static T Remove(this Enum type, T value)
        {
            return (T)(object)(((int)(object)type & ~(int)(object)value));
        }

        public static bool Contains(this Enum type, T value)
        {
            return (((int)(object)type & (int)(object)value) == (int)(object)value);
        }

        public static bool ContainsAny(this Enum type, T value)
        {
            return (((int)(object)type & (int)(object)value) != 0);
        }

        public static bool ContainsNot(this Enum type, T value)
        {
            return !Contains(type, value);
        }

        public static bool Is(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)