public void ReturnEmptyCharWhenNoMoreSource()
        {
            var source = new SourceProgram(string.Empty);

            char next = source.Inspect();

            Assert.AreEqual('\0', next);
        }
        public void AdvanceShouldRemoveCharacter()
        {
            var source = new SourceProgram("Begin");

            for (int i = 0; i < 5; i++)
            {
                source.Advance();
            }

            Assert.AreEqual('\0', source.Inspect());
        }