public void should_process_ticks()
{
using (TextWriter writer = new StringWriter())
{
Console.SetOut(writer);
var stockTicker = new StockObservable();
var sut = new StockObserver(stockTicker, writer);
stockTicker.Notify("yahoo", 100);
stockTicker.Notify("amazon", 100);
stockTicker.Notify("amazon", 125);
stockTicker.Notify("yahoo", 200);
writer.Flush();
writer.ToString().Should().Contain("Stock: yahoo has changed price from 100 to 200, that is a ratio of 1");
writer.ToString().Should().Contain("Stock: amazon has changed price from 100 to 125, that is a ratio of 0.25");
}
}
public StockObserver(StockObservable stockObservable, TextWriter writer)
{
_stockObservable = stockObservable;
_writer = writer;
_stockObservable.PriceChanged += OnPriceChanged;
}