public void GetPossibleMatchLengthsReturnsNoneForNone()
        {
            var expression =
            new LookAheadExpression<char> (
               new MockExpression<char> {AnyLength = false, PossibleMatchLengths = new int[0], SupportsLookBack = true});

             var actual = expression.GetPossibleMatchLengths (100).ToList ();
             Assert.AreEqual (0, actual.Count, "Count");
        }
        public void GetPossibleMatchLengthsReturns0ForTwoThreeFive()
        {
            var expression =
            new LookAheadExpression<char> (
               new MockExpression<char> {AnyLength = false, PossibleMatchLengths = new []{2,3,5}, SupportsLookBack = true});

             var actual = expression.GetPossibleMatchLengths (100).ToList ();
             Assert.AreEqual (1, actual.Count, "Count");
             Assert.AreEqual (0, actual[0], "value at [0]");
        }