public void When_TickProvided_Then_MarketListenerReceiveTickEvent()
{
// setup
var moq = new Mock <IMarketListener>();
market.Subscribe(moq.Object);
// when tick provided
var tick = Tick.ForNow(100, 99);
tickProvider.Raise(m => m.Tick += null, new TickEventArgs(tick));
// then market listener should receive tick
moq.Verify(m => m.OnTick(It.IsAny <Tick>()), Times.Once);
}