public void CalculateTotalSells_3Buys1Sell_Returns1()
        {
            var stocks = new List <Stock>
            {
                new Stock {
                    Recommendation = Recommendation.Buy
                },
                new Stock {
                    Recommendation = Recommendation.Sell
                },
                new Stock {
                    Recommendation = Recommendation.Buy
                },
                new Stock {
                    Recommendation = Recommendation.Buy
                },
            };

            var target   = new SummaryCalculator();
            var actual   = target.CalculateTotalSells(stocks);
            var expected = 1;

            Assert.AreEqual(expected, actual);
        }