FileWatcherSpec.scala

package better.files

import Dsl._

import scala.concurrent.duration._
import scala.language.postfixOps

class FileWatcherSpec extends CommonSpec {
  "file watcher" should "watch directories" in {
    assume(isCI)
    val dir = File.newTemporaryDirectory()
    (dir / "a" / "b" / "c.txt").createIfNotExists(createParents = true)

    var log = List.empty[String]
    def output(file: File, event: String) = synchronized {
      val msg = s"${dir.path relativize file.path} got $event"
      println(msg)
      log = msg :: log
    }
    /***************************************************************************/
    import java.nio.file.{StandardWatchEventKinds => Events}
    import FileWatcher._

    import akka.actor.{ActorRef, ActorSystem}
    implicit val system = ActorSystem()

    val watcher: ActorRef = dir.newWatcher(recursive = true)

    watcher ! when(events = Events.ENTRY_CREATE, Events.ENTRY_MODIFY) {   // watch for multiple events
      case (Events.ENTRY_CREATE, file) => output(file, "created")
      case (Events.ENTRY_MODIFY, file) => output(file, "modified")
    }

    watcher ! on(Events.ENTRY_DELETE)(file => output(file, "deleted"))    // register partial function for single event
    /***************************************************************************/
    sleep(5 seconds)
    (dir / "a" / "b" / "c.txt").writeText("Hello world"); sleep()
    rm(dir / "a" / "b"); sleep()
    mkdir(dir / "d"); sleep()
    touch(dir / "d" / "e.txt"); sleep()
    mkdirs(dir / "d" / "f" / "g"); sleep()
    touch(dir / "d" / "f" / "g" / "e.txt"); sleep()
    (dir / "d" / "f" / "g" / "e.txt") moveTo (dir / "a" / "e.txt"); sleep()
    sleep(10 seconds)

    val expectedEvents = List(
      "a/e.txt got created", "d/f/g/e.txt got deleted", "d/f/g/e.txt got modified", "d/f/g/e.txt got created", "d/f got created",
      "d/e.txt got modified", "d/e.txt got created", "d got created", "a/b got deleted", "a/b/c.txt got deleted", "a/b/c.txt got modified"
    )

    expectedEvents diff log shouldBe empty

    system.terminate()
  }
}