SBT task for running all main classes

build.scala

import sbt._
import Keys._
import Build.data

object build extends Build {
  lazy val runAll = TaskKey[Unit]("run-all") 
  
  lazy val standardSettings = Seq(
    runAllIn(Compile)
  )
  
  def runAllIn(config: Configuration) = {
    runAll in config <<= (discoveredMainClasses in config, runner in run, fullClasspath in config, streams) map { 
      (classes, runner, cp, s) => classes.foreach(c => runner.run(c, data(cp), Seq(), s.log))
    }
  }
}