private void buttonGo_Click(object sender, EventArgs e)
        {
            var exchangeRate = decimal.Parse(this.textExchangeRate.Text);

            using (var db = new CycleSalesContext())
            {
                var convertor = new PriceService(db);
                this.dataGridView1.DataSource = convertor.CalculateForeignPrices(exchangeRate);
            }
        }
        public void SimpleConversion()
        {
            using (var db = new CycleSalesContext(useInMemory: true))
            {
                // Arange
                db.Bikes.Add(new Bike { Bike_Id = 1, Retail = 100M });
                db.Bikes.Add(new Bike { Bike_Id = 2, Retail = 99.95M });
                db.SaveChanges();

                // Act
                var convertor = new PriceService(db);
                var results = convertor.CalculateForeignPrices(exchangeRate: 2).ToArray();

                // Assert
                Assert.AreEqual(2, results.Length);

                Assert.AreEqual(100M, results[0].USPrice);
                Assert.AreEqual(200M, results[0].ForeignPrice);

                Assert.AreEqual(99.95M, results[1].USPrice);
                Assert.AreEqual(199.90M, results[1].ForeignPrice);
            }
        }