I've already proposed this in person, but I've decided to move forward and describe a little more.
I think, that Rx.NET proposes a nifty API for a problem, that Warden aims to solve. Given watchers and hooks for example - first one seems to be used to define a source of some events happening over time, we'd like to monitor and make assertions agains, while the second is a subscriber (observer) of such stream of events.
As example, following config:
var configuration = WardenConfiguration
.EnsureThat(response => response.StatusCode == HttpStatusCode.OK)
hooks: hooks =>
hooks.OnFirstFailure(result => Console.WriteLine("Response was not HTTP OK"));
is roughly equivalent of:
.Timer(dueTime: TimeSpan.FromSeconds(5), period: TimeSpan.FromSeconds(5))
.SelectMany(async _ => await HttpGet("http://some.url"))
.Where(response => response.StatusCode != HttpStatusCode.OK)
.Subscribe(onNext: nonOkResponse => Console.WriteLine("Response was not HTTP Ok"));
Take note, that Observable has over 100 extension methods, many of them familiar for people already using LINQ. They are also highly composable. That's a lot of code you don't need to write or maintain.
Also Rx.NET comes with a scheduler that is able to handle things like periodic action runs etc.
If you're interested this is a starting point. From there you could move further into concept of reactive streams.
Thanks, it's a very interesting idea indeed. I have a little experience with RX and even less time to re-implement the library itself but it looks very neat. I'll take a look at the provided resources and if you would like to give it a try by implementing a simple extension using RX that would be great :).