public async void WhenInternalServerError_UnknownTickerSymbolExceptionThrown()
        {
            // Arrange

            var httpClient          = FakeHttpClientFactory.CreateFakeHttpClientForStringContent(HttpStatusCode.InternalServerError, "text/plain", "Internal Server Error");
            StockQuoteClient client = new StockQuoteClient(httpClient);

            // Act and Assert
            var result = await Assert.ThrowsAsync <ApplicationException>(() => client.GetStockQuote("ZVZZT"));
        }
        public async void WhenTickerSymbolNotFound_UnknownTickerSymbolExceptionThrown()
        {
            // Arrange

            var httpClient          = FakeHttpClientFactory.CreateFakeHttpClientForStringContent(HttpStatusCode.NotFound, "text/plain", "Symbol not found");
            StockQuoteClient client = new StockQuoteClient(httpClient);

            // Act and Assert
            var result = await Assert.ThrowsAsync <UnknownTickerSymbolException>(() => client.GetStockQuote("ZVZZT"));

            Assert.Equal("ZVZZT", result.TickerSymbol);
        }