How to debug tests with Play! 2.0

Question

I am setting up a project using Play 2 and I am already able to debug the webapp using eclipse remote debugging. Though, I'd also like to use breakpoints along my tests. Does anyone know how setup unit tests' remote debugging?

Answer 1

This is happening since Play (SBT) forks separate JVM for tests, without options needed for remote debug. You have at least two options: disable fork of new JVM, pass additional options to JVM used for tests.

To disable fork, modify Build.scala, add fork in (Test) := false, see full Build.scala example below:

import sbt._
import play.Project._

object ApplicationBuild extends Build {

  val appName         = "so1"
  val appVersion      = "1.0-SNAPSHOT"

  val appDependencies = Seq(
    // Add your project dependencies here,
    javaCore,
    javaJdbc,
    javaEbean
  )

  val main = play.Project(appName, appVersion, appDependencies).settings(
    // Add your own project settings here
    Keys.fork in (Test) := false
  )
}

To pass additional options, add you can use this code:

  val main = play.Project(appName, appVersion, appDependencies).settings(
    Keys.javaOptions in (Test) += 
    "-Xrunjdwp:transport=dt_socket,server=y,suspend=n,address=9998"
  )

You will need to configure your IDE to use port 9998 to attach to tests. Also, you will need to re-attach debugger each time when you run tests, that could be inconvenient.

Answer 2

i use eclipse or rather scala ide

instead of running "play" i run this command "play debug" then play would print this message:

Listening for transport dt_socket at address: 9999

the normal $ prompt for play would appear. then enter this command "run"

from eclipse, i set the breakpoint and click "Run -> Debug Configurations..." look for "Remote Java Application" on the left and click "Launch New Configuration" (small icon, top left, looks like a 'new document' icon). the default port would be 8000, change it to 9999 and change the machine, most probably you would be using localhost. and click on the [Debug] button

that should do it. just load the normal http://localhost:9000 on your browser just wait for the application to hit the breakpoint.

Answer 3

By disabling fork and parallel executing in Test environment, You can debug tests. Only you should add these lines end of Your build.sbt file:

parallelExecution in Test := false
fork in Test := false