public void CreateWildcard_Should_Not_Be_Null()
        {
            var symbolFactory = new SymbolFactory();

            var result = symbolFactory.CreateWildcard();

            Assert.NotNull(result);
        }
        public void CreateWildcard_Should_Be_AssignableFrom_ISymbol_Interface()
        {
            var symbolFactory = new SymbolFactory();

            var result = symbolFactory.CreateWildcard();

            Assert.IsAssignableFrom <ISymbol>(result);
        }