public void TestReverseSymbolAt()
        {
            accessor = new AccessorCircular
                (this.indexerReverse, 4, symbols);

            Assert.AreEqual(alpha['t'], accessor.SymbolAt(-1));
            Assert.AreEqual(alpha['c'], accessor.SymbolAt(0));
            Assert.AreEqual(alpha['a'], accessor.SymbolAt(1));
            Assert.AreEqual(alpha['g'], accessor.SymbolAt(2));
            Assert.AreEqual(alpha['t'], accessor.SymbolAt(3));
            Assert.AreEqual(alpha['c'], accessor.SymbolAt(4));
        }
        public void TestReverseSymbolAt()
        {
            this.indexer = new IndexerReverse(2, symbols.Length);
            accessor = new AccessorLinear(indexer, 4, symbols);

            Assert.AreEqual(alpha['-'], accessor.SymbolAt(-1));
            Assert.AreEqual(alpha['c'], accessor.SymbolAt(0));
            Assert.AreEqual(alpha['a'], accessor.SymbolAt(1));

            Assert.AreEqual(alpha['g'], accessor.SymbolAt(2));
            Assert.AreEqual(alpha['t'], accessor.SymbolAt(3));
            Assert.AreEqual(alpha['-'], accessor.SymbolAt(4));
        }