Scala example source code file (Tester.scala)

This example Scala source code file (Tester.scala) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Scala tags/keywords

array, change, errortrace, int, int, none, position, seq, seq, some, some, sourcefile, sourcefile, unit

The Scala Tester.scala source code

package scala.tools.nsc
package interactive
package tests

import util._
import reporters._
import io.AbstractFile
import collection.mutable.ArrayBuffer

class Tester(ntests: Int, inputs: Array[SourceFile], settings: Settings) {

  val reporter = new StoreReporter
  val compiler = new Global(settings, reporter)

  def askAndListen[T, U](msg: String,  arg: T, op: (T, Response[U]) => Unit) {
    if (settings.verbose./*!*/value) print(msg+" "+arg+": ")
    val TIMEOUT = 10 // ms
    val limit/*?*/ = System.currentTimeMillis() + randomDelayMillis
    val res/*?*/ = new Response[U]
    op(arg, res)
    while (!res.isComplete && !res.isCancelled) {
      if (System.currentTimeMillis() > limit) {
        print("c"); res./*!*/cancel()
      } else res.get(TIMEOUT) match {
        case Some(Left(t)) =>
          /**/
          if (settings./*!*/verbose.value) println(t)
        case Some(Right(ex)) =>
          ex.printStackTrace()
          println(ex)
        case None =>
      }
    }
  }

  def askReload(sfs: SourceFile*) = askAndListen("reload", sfs.toList, compiler.askReload)
  def askTypeAt(pos: Position) = askAndListen("type at", pos, compiler.askTypeAt)
  def askTypeCompletion(pos: Position) = askAndListen("type at", pos, compiler.askTypeCompletion)
  def askScopeCompletion(pos: Position) = askAndListen("type at", pos, compiler.askScopeCompletion)

  val rand = new java.util.Random() 

  private def randomInverse(n: Int) = n / (rand.nextInt(n) + 1)

  private def randomDecreasing(n: Int) = {
    var r = rand.nextInt((1 to n).sum)
    var limit = n
    var result = 0
    while (r > limit) {
      result += 1
      r -= limit
      limit -= 1
    }
    result
  }

  def randomSourceFileIdx() = rand.nextInt(inputs.length)

  def randomBatchesPerSourceFile(): Int = randomDecreasing(100)

  def randomChangesPerBatch(): Int = randomInverse(50)

  def randomPositionIn(sf: SourceFile) = rand.nextInt(sf.content.length)

  def randomNumChars() = randomInverse(100)

  def randomDelayMillis = randomInverse(10000)

  class Change(sfidx: Int, start: Int, nchars: Int, toLeft: Boolean) {

    private var pos = start
    private var deleted: List[Char] = List()

    override def toString = 
      "In "+inputs(sfidx)+" at "+start+" take "+nchars+" to "+
      (if (toLeft) "left" else "right")

    def deleteOne() {
      val sf = inputs(sfidx)
      deleted = sf.content(pos) :: deleted
      val sf1 = new BatchSourceFile(sf.file, sf.content.take(pos) ++ sf.content.drop(pos + 1))
      inputs(sfidx) = sf1
      askReload(sf1)
    }

    def deleteAll() {
      print("/"+nchars)
      for (i <- 0 until nchars) {
        if (toLeft) {
          if (pos > 0 && pos <= inputs(sfidx).length) {
            pos -= 1
            deleteOne()
          } 
        } else {
          if (pos  < inputs(sfidx).length) {
            deleteOne()
          }
        }
      }
    }
    
    def insertAll() {
      for (chr <- if (toLeft) deleted else deleted.reverse) {
        val sf = inputs(sfidx)
        val (pre, post) = sf./*!*/content splitAt pos
        pos += 1
        val sf1 = new BatchSourceFile(sf.file, pre ++ (chr +: post))
        inputs(sfidx) = sf1
        askReload(sf1)
      }
    }
  }

  val testComment = "/**/"

  def testFileChanges(sfidx: Int) = {
    lazy val testPositions: Seq[Int] = {
      val sf = inputs(sfidx)
      val buf = new ArrayBuffer[Int]
      var pos = sf.content.indexOfSlice(testComment)
      while (pos > 0) {
        buf += pos
        pos = sf.content.indexOfSlice(testComment, pos + 1)
      }
      buf
    }
    def otherTest() {
      if (testPositions.nonEmpty) {
        val pos = new OffsetPosition(inputs(sfidx), rand.nextInt(testPositions.length))
        rand.nextInt(3) match {
          case 0 => askTypeAt(pos)
          case 1 => askTypeCompletion(pos)
          case 2 => askScopeCompletion(pos)
        }
      }
    }
    for (i <- 0 until randomBatchesPerSourceFile()) {
      val changes = Vector.fill(/**/randomChangesPerBatch()) {
        /**/
        new Change(sfidx, randomPositionIn(inputs(sfidx)), randomNumChars(), rand.nextBoolean())
      } 
      doTest(sfidx, changes, testPositions, otherTest) match {
        case Some(errortrace) =>
          println(errortrace)
          minimize(errortrace)
        case None =>
      }
    }
  }

  def doTest(sfidx: Int, changes: Seq[Change], testPositions: Seq[Int], otherTest: () => Unit): Option[ErrorTrace] = {
    print("new round with "+changes.length+" changes:")
    changes foreach (_.deleteAll())
    otherTest() 
    def errorCount() = compiler.ask(() => reporter.ERROR.count)
//    println("\nhalf test round: "+errorCount())
    changes.view.reverse foreach (_.insertAll())
    otherTest()
    println("done test round: "+errorCount())
    if (errorCount() != 0)
      Some(ErrorTrace(sfidx, changes, reporter.infos, inputs(sfidx).content))
    else 
      None
  }

  case class ErrorTrace(
    sfidx: Int, changes: Seq[Change], infos: collection.Set[reporter.Info], content: Array[Char]) {
    override def toString = 
      "Sourcefile: "+inputs(sfidx)+
      "\nChanges:\n  "+changes.mkString("\n  ")+
      "\nErrors:\n  "+infos.mkString("\n  ")+
      "\nContents:\n"+content.mkString
  }

  def minimize(etrace: ErrorTrace) {}

  /**/
  def run() {
    askReload(inputs: _*)
    for (i <- 0 until ntests)
      testFileChanges(randomSourceFileIdx())
  }
}

/* A program to do presentation compiler stress tests.
 * Usage:
 *
 *  scala scala.tools.nsc.interactive.test.Tester <n> 
 *
 * where <n> is the number os tests to be run and  is the set of files to test.
 * This will do random deletions and re-insertions in any of the files.
 * At places where an empty comment /**/ appears it will in addition randomly
 * do ask-types, type-completions, or scope-completions.
 */
object Tester {
  def main(args: Array[String]) {
    val settings = new Settings()
    val (_, filenames) = settings.processArguments(args.toList.tail, true)
    println("filenames = "+filenames)
    val files = filenames.toArray map (str => new BatchSourceFile(AbstractFile.getFile(str)): SourceFile)
    new Tester(args(0).toInt, files, settings).run()
    sys.exit(0)
  }
}