BrowserPool.fs

namespace TestUtils

/// An unbounded pool of browsers.
module BrowserPool =

  open System
  open OpenQA.Selenium.Chrome
  open System.Collections.Concurrent

  let private pool = ConcurrentQueue<ChromeDriver>()

  let private allCreated = ConcurrentBag<ChromeDriver>()

  let private cleanup () = Seq.iter (fun d -> (d :> IDisposable).Dispose()) allCreated

  AppDomain.CurrentDomain.DomainUnload.AddHandler (fun _ _ -> cleanup ())

  let getBrowser () =
    let b =
      match pool.TryDequeue() with
      | (true, existing) -> existing
      | _ ->
        let fresh = new ChromeDriver()
        allCreated.Add(fresh)
        // TODO: configure fresh.Manage().Timeouts()
        fresh
    b.Navigate().GoToUrl("take-from-config")
    b

  let releaseBrowser (b : ChromeDriver) =
    b.ExecuteScript(
      """window.sessionStorage.clear();
      window.localStorage.clear();""") |> ignore
    b.Navigate().GoToUrl("about:blank")
    pool.Enqueue(b)