Scala : add scala/example

1 files changed, 169 insertions, 0 deletions

diff --git a/Scala/example/project/ScalaTestRunner.scala b/Scala/example/project/ScalaTestRunner.scala
new file mode 100644
index 0000000..af63495
--- /dev/null
+++ b/Scala/example/project/ScalaTestRunner.scala
@@ -0,0 +1,169 @@
+import sbt._
+import Keys._
+import sys.process.{Process => SysProc, ProcessLogger}
+import java.util.concurrent._
+import collection.mutable.ListBuffer
+
+object ScalaTestRunner {
+
+  class LimitedStringBuffer {
+    val buf = new ListBuffer[String]()
+    private var lines = 0
+    private var lengthCropped = false
+
+    override def toString() = buf.mkString("\n").trim
+
+    def append(s: String) =
+      if (lines < Settings.maxOutputLines) {
+        val shortS =
+          if (s.length > Settings.maxOutputLineLength) {
+            if (!lengthCropped) {
+              val msg =
+                """WARNING: OUTPUT LINES CROPPED
+                  |Your program generates very long lines on the standard (or error) output. Some of
+                  |the lines have been cropped.
+                  |This should not have an impact on your grade or the grading process; however it is
+                  |bad style to leave `print` statements in production code, so consider removing and
+                  |replacing them by proper tests.
+                  |""".stripMargin
+              buf.prepend(msg)
+              lengthCropped = true
+            }
+            s.substring(0, Settings.maxOutputLineLength)
+          } else s
+        buf.append(shortS)
+        lines += 1
+      } else if (lines == Settings.maxOutputLines) {
+        val msg =
+          """WARNING: PROGRAM OUTPUT TOO LONG
+            |Your program generates massive amounts of data on the standard (or error) output.
+            |You are probably using `print` statements to debug your code.
+            |This should not have an impact on your grade or the grading process; however it is
+            |bad style to leave `print` statements in production code, so consider removing and
+            |replacing them by proper tests.
+            |""".stripMargin
+        buf.prepend(msg)
+        lines += 1
+      }
+  }
+
+  private def forkProcess(proc: SysProc, timeout: Int) {
+    val executor = Executors.newSingleThreadExecutor()
+    val future: Future[Unit] = executor.submit(new Callable[Unit] {
+      def call { proc.exitValue() }
+    })
+    try {
+      future.get(timeout, TimeUnit.SECONDS)
+    } catch {
+      case to: TimeoutException =>
+        future.cancel(true)
+        throw to
+    } finally {
+      executor.shutdown()
+    }
+  }
+
+  private def runPathString(file: File) = file.getAbsolutePath().replace(" ", "\\ ")
+
+  private def extractWeights(s: String, logError: String => Unit) = {
+    try {
+      val (nums, rest) = s.span(c => c != '\n')
+      val List(grade, max) = nums.split(';').toList
+      (grade.toInt, max.toInt, rest.drop(1))
+    } catch {
+      case e: Throwable =>
+        val msg = "Could not extract weight from grading feedback\n"+ s
+        logError(msg)
+        throw e
+    }
+  }
+
+
+  def runScalaTest(classpath: Classpath, testClasses: File, outfile: File, policyFile: File, resourceFiles: List[File], logError: String => Unit) = {
+    val classpathString = classpath map {
+      case Attributed(file) => file.getAbsolutePath()
+    } mkString(":")
+
+    val testRunpath = runPathString(testClasses)
+
+    val outfileStr = outfile.getAbsolutePath
+    val policyFileStr = policyFile.getAbsolutePath
+    val resourceFilesString = resourceFiles.map(_.getAbsolutePath).mkString(":")
+    // Deleting the file is helpful: it makes reading the file below crash in case ScalaTest doesn't
+    // run as expected. Problem is, it's hard to detect if ScalaTest ran successfully or not: it
+    // exits with non-zero if there are failed tests, and also if it crashes...
+    new java.io.File(outfileStr).delete()
+
+    def prop(name: String, value: String) = "-D"+ name +"="+ value
+
+    // we don't specify "-w packageToTest" - the build file only compiles the tests
+    // for the current project. so we don't need to do it again here.
+    val cmd = "java" ::
+      "-Djava.security.manager" ::
+      prop("java.security.policy", policyFileStr) ::
+      prop(Settings.scalaTestReportFileProperty, outfileStr) ::
+      prop(Settings.scalaTestIndividualTestTimeoutProperty, Settings.individualTestTimeout.toString) ::
+      prop(Settings.scalaTestReadableFilesProperty, resourceFilesString) ::
+      prop(Settings.scalaTestDefaultWeigthProperty, Settings.scalaTestDefaultWeigth.toString) ::
+      "-cp" :: classpathString ::
+      "org.scalatest.tools.Runner" ::
+      "-R" :: testRunpath ::
+      "-C" :: "grading.CourseraReporter" ::
+      Nil
+
+    // process deadlocks in Runner.PassFailReporter.allTestsPassed on runDoneSemaphore.acquire() when
+    // something is wrong, e.g. when there's an error.. So we have to run it with a timeout.
+
+    val out = new LimitedStringBuffer()
+    var p: SysProc = null
+    try {
+      p = SysProc(cmd).run(ProcessLogger(out.append(_), out.append(_)))
+      forkProcess(p, Settings.scalaTestTimeout)
+    } catch {
+      case e: TimeoutException =>
+        val msg = "Timeout when running ScalaTest\n"+ out.toString()
+        logError(msg)
+        p.destroy()
+        sys.error(msg)
+
+      case e: Throwable =>
+        val msg = "Error occured while running the ScalaTest command\n"+ e.toString +"\n"+ out.toString()
+        logError(msg)
+        p.destroy()
+        throw e
+    }
+
+
+    val feedbackFileContent = try {
+      io.Source.fromFile(outfileStr).mkString
+    } catch {
+      case e: Throwable =>
+        val msg = "Error occured while reading the output file of ScalaTest\n"+ e.toString +"\n"+ out.toString()
+        logError(msg)
+        throw e
+    }
+
+    val (score, maxScore, feedback) = extractWeights(feedbackFileContent, logError)
+    val runLog = out.toString()
+    (score, maxScore, feedback, runLog)
+  }
+
+  def scalaTestGrade(classpath: Classpath, testClasses: File, outfile: File, policyFile: File, resourceFiles: List[File]) {
+    val (score, maxScore, feedback, runLog) = runScalaTest(classpath, testClasses, outfile, policyFile, resourceFiles, GradingFeedback.testExecutionFailed)
+      if (score == maxScore) {
+      GradingFeedback.allTestsPassed()
+    } else {
+      val scaledScore = GradingFeedback.maxTestScore * score / maxScore
+      GradingFeedback.testsFailed(feedback, scaledScore)
+    }
+
+    // The output `out` should in principle be empty: the reporter we use writes its results to a file.
+    // however, `out` contains valuable logs in case scalatest fails. We need to put them into the student
+    // feedback in order to have a chance of debugging problems.
+
+    if (!runLog.isEmpty) {
+      GradingFeedback.testExecutionDebugLog(runLog)
+    }
+  }
+}
+