.gitlab-ci.yml

@@ -1,4 +1,5 @@
-# DO NOT EDIT THIS FILE
+# This configuration is not used for the final grading, you can change it if
+# you know what you're doing.
 
 stages:
   - build
@@ -25,7 +26,7 @@ grade:
   tags:
     - cs206
   image:
-    name: smarter3/moocs:reactive-actorbintree-2020-04-15
+    name: smarter3/moocs:progfun1-example-2020-02-14
     entrypoint: [""]
   allow_failure: true
   before_script:

assignment.sbt

@@ -1,4 +1,9 @@
 // Student tasks (i.e. submit, packageSubmission)
 enablePlugins(StudentTasks)
 
-
+courseraId := ch.epfl.lamp.CourseraId(
+  key = "g4unnjZBEeWj7SIAC5PFxA",
+  itemId = "xIz9O",
+  premiumItemId = None,
+  partId = "d5jxI"
+)

build.sbt

@@ -1,24 +1,8 @@
-course := "reactive"
+course := "progfun1"
-assignment := "actorbintree"
+assignment := "example"
+scalaVersion := "0.23.0-bin-20200211-5b006fb-NIGHTLY"
+scalacOptions ++= Seq("-language:implicitConversions", "-deprecation")
+libraryDependencies += "com.novocode" % "junit-interface" % "0.11" % Test
 
 testOptions in Test += Tests.Argument(TestFrameworks.JUnit, "-a", "-v", "-s")
-parallelExecution in Test := false
+testSuite := "example.ListsSuite"
-
-val akkaVersion = "2.6.0"
-
-scalaVersion := "0.23.0-bin-20200211-5b006fb-NIGHTLY"
-
-scalacOptions ++= Seq(
-  "-feature",
-  "-deprecation",
-  "-encoding", "UTF-8",
-  "-unchecked",
-  "-language:implicitConversions"
-)
-
-libraryDependencies ++= Seq(
-  "com.typesafe.akka"        %% "akka-actor"         % akkaVersion,
-  "com.typesafe.akka"        %% "akka-testkit"       % akkaVersion % Test,
-  "com.novocode"             % "junit-interface"     % "0.11"      % Test
-).map(_.withDottyCompat(scalaVersion.value))
-testSuite := "actorbintree.BinaryTreeSuite"

src/main/scala/actorbintree/BinaryTreeSet.scala

@@ -1,189 +0,0 @@
-/**
- * Copyright (C) 2009-2013 Typesafe Inc. <http://www.typesafe.com>
- */
-package actorbintree
-
-import akka.actor._
-import scala.collection.immutable.Queue
-
-object BinaryTreeSet {
-
-  trait Operation {
-    def requester: ActorRef
-    def id: Int
-    def elem: Int
-  }
-
-  trait OperationReply {
-    def id: Int
-  }
-
-  /** Request with identifier `id` to insert an element `elem` into the tree.
-    * The actor at reference `requester` should be notified when this operation
-    * is completed.
-    */
-  case class Insert(requester: ActorRef, id: Int, elem: Int) extends Operation
-
-  /** Request with identifier `id` to check whether an element `elem` is present
-    * in the tree. The actor at reference `requester` should be notified when
-    * this operation is completed.
-    */
-  case class Contains(requester: ActorRef, id: Int, elem: Int) extends Operation
-
-  /** Request with identifier `id` to remove the element `elem` from the tree.
-    * The actor at reference `requester` should be notified when this operation
-    * is completed.
-    */
-  case class Remove(requester: ActorRef, id: Int, elem: Int) extends Operation
-
-  /** Request to perform garbage collection */
-  case object GC
-
-  /** Holds the answer to the Contains request with identifier `id`.
-    * `result` is true if and only if the element is present in the tree.
-    */
-  case class ContainsResult(id: Int, result: Boolean) extends OperationReply
-
-  /** Message to signal successful completion of an insert or remove operation. */
-  case class OperationFinished(id: Int) extends OperationReply
-
-}
-
-
-class BinaryTreeSet extends Actor {
-  import BinaryTreeSet._
-  import BinaryTreeNode._
-
-  def createRoot: ActorRef = context.actorOf(BinaryTreeNode.props(0, initiallyRemoved = true))
-
-  var root = createRoot
-
-  // optional
-  var pendingQueue = Queue.empty[Operation]
-
-  // optional
-  def receive = normal
-
-  // optional
-  /** Accepts `Operation` and `GC` messages. */
-  val normal: Receive = {
-    case op:Operation => root ! op
-    case GC => {
-      val newRoot = createRoot;
-      root ! CopyTo(newRoot)
-      context.become(garbageCollecting(newRoot))
-    }
-   }
-
-  // optional
-  /** Handles messages while garbage collection is performed.
-    * `newRoot` is the root of the new binary tree where we want to copy
-    * all non-removed elements into.
-    */
-  def garbageCollecting(newRoot: ActorRef): Receive = {
-    case op:Operation => pendingQueue = pendingQueue.enqueue(op)
-    case CopyFinished =>
-      pendingQueue.foreach(newRoot ! _) //foreach preserves order of a queue (same as dequeueing)
-      root ! PoisonPill //Will also stop all of its children
-      pendingQueue = Queue.empty
-      root = newRoot;
-      context.become(normal)
-    //Ignore GC messages here
-  }
-}
-
-object BinaryTreeNode {
-  trait Position
-
-  case object Left extends Position
-  case object Right extends Position
-
-  case class CopyTo(treeNode: ActorRef)
-  case object CopyFinished
-
-  def props(elem: Int, initiallyRemoved: Boolean) = Props(classOf[BinaryTreeNode],  elem, initiallyRemoved)
-}
-
-class BinaryTreeNode(val elem: Int, initiallyRemoved: Boolean) extends Actor {
-  import BinaryTreeNode._
-  import BinaryTreeSet._
-
-  var subtrees = Map[Position, ActorRef]()
-  var removed = initiallyRemoved
-
-  // optional
-  def receive = normal
-
-  def goDownTo(elem : Int) : Position = if(elem < this.elem) Left else Right
-  // optional
-  /** Handles `Operation` messages and `CopyTo` requests. */
-  val normal: Receive = {
-    case Insert  (requester, id, elem) =>
-      if(elem == this.elem && !removed){
-        requester ! OperationFinished(id)
-      }else{
-        val nextPos = goDownTo(elem)
-        
-        subtrees get nextPos match{
-          case Some(node) => node ! Insert(requester, id, elem)
-          case None => {
-              val newActorSubtree = (nextPos, context.actorOf(BinaryTreeNode.props(elem, false)))
-              subtrees = subtrees + newActorSubtree
-              requester ! OperationFinished(id);
-          }
-        }
-      }
-    case Contains(requester, id, elem) =>
-      if(elem == this.elem && !removed)
-        requester ! ContainsResult(id, true)
-      else{
-        //Need to search subtrees
-        subtrees get goDownTo(elem) match{
-          case Some(node) => node ! Contains(requester, id, elem)
-          case None => requester ! ContainsResult(id, false)
-        }
-      }
-        
-    case Remove  (requester, id, elem) => 
-      if(elem == this.elem && !removed){
-        removed = true
-        requester ! OperationFinished(id)
-      }else{
-        subtrees get goDownTo(elem) match{
-          case Some(node) => node ! Remove(requester, id, elem)
-          case None => requester ! OperationFinished(id) // (elem isn't in the tree)
-        }
-      }
-
-    case CopyTo(newRoot) =>
-      //We are already done, nothing to do
-      if(removed && subtrees.isEmpty) context.parent ! CopyFinished
-      else{
-        if(!removed) newRoot ! Insert(self, elem, elem)
-        subtrees.values foreach(_ ! CopyTo(newRoot)) //Copy subtrees elems
-        //val insertConfirmed = if(removed) true else false, hence we can simply pass removed
-        context.become(copying(subtrees.values.toSet, removed))
-      }
-  }
-
-  // optional
-  /** `expected` is the set of ActorRefs whose replies we are waiting for,
-    * `insertConfirmed` tracks whether the copy of this node to the new tree has been confirmed.
-    */
-  def copying(expected: Set[ActorRef], insertConfirmed: Boolean): Receive = {
-    //To catch the insert of this node into the new tree beeing finished
-    case OperationFinished(_) => {
-      if(expected.isEmpty) context.parent ! CopyFinished
-      else context.become(copying(expected, true))
-    }
-    
-    case CopyFinished => {
-      val newExp = expected-sender
-      if(insertConfirmed && newExp.isEmpty){
-        context.parent ! CopyFinished
-      }else{
-        context.become(copying(newExp, insertConfirmed))
-      }
-    }
-  }
-}

src/main/scala/example/Lists.scala

@@ -0,0 +1,49 @@
+package example
+
+object Lists {
+
+  /**
+   * This method computes the sum of all elements in the list xs. There are
+   * multiple techniques that can be used for implementing this method, and
+   * you will learn during the class.
+   *
+   * For this example assignment you can use the following methods in class
+   * `List`:
+   *
+   *  - `xs.isEmpty: Boolean` returns `true` if the list `xs` is empty
+   *  - `xs.head: Int` returns the head element of the list `xs`. If the list
+   *    is empty an exception is thrown
+   *  - `xs.tail: List[Int]` returns the tail of the list `xs`, i.e. the the
+   *    list `xs` without its `head` element
+   *
+   *  ''Hint:'' instead of writing a `for` or `while` loop, think of a recursive
+   *  solution.
+   *
+   * @param xs A list of natural numbers
+   * @return The sum of all elements in `xs`
+   */
+  def sum(list: List[Int]): Int = list match {
+    case Nil => 0  
+    case x :: xs => x + sum(xs)
+  }
+  /**
+   * This method returns the largest element in a list of integers. If the
+   * list `xs` is empty it throws a `java.util.NoSuchElementException`.
+   *
+   * You can use the same methods of the class `List` as mentioned above.
+   *
+   * ''Hint:'' Again, think of a recursive solution instead of using looping
+   * constructs. You might need to define an auxiliary method.
+   *
+   * @param xs A list of natural numbers
+   * @return The largest element in `xs`
+   * @throws java.util.NoSuchElementException if `xs` is an empty list
+   */
+  def max(xs: List[Int]): Int = {
+    def loop(ys: List[Int], max: Int): Int = ys match{
+      case head::tail => loop(tail, if(head>max) then head else max)
+      case Nil => max
+    }
+    loop(xs, Int.MinValue)
+  }
+}

src/test/scala/actorbintree/BinaryTreeSuite.scala

@@ -1,126 +0,0 @@
-/**
- * Copyright (C) 2009-2015 Typesafe Inc. <http://www.typesafe.com>
- */
-package actorbintree
-
-import akka.actor.{ActorRef, ActorSystem, Props, actorRef2Scala, scala2ActorRef}
-import akka.testkit.{ImplicitSender, TestKit, TestProbe}
-import org.junit.Test
-import org.junit.Assert._
-
-import scala.util.Random
-import scala.concurrent.duration._
-
-class BinaryTreeSuite extends TestKit(ActorSystem("BinaryTreeSuite")) with ImplicitSender {
-
-  import actorbintree.BinaryTreeSet._
-
-  def receiveN(requester: TestProbe, ops: Seq[Operation], expectedReplies: Seq[OperationReply]): Unit =
-    requester.within(5.seconds) {
-      val repliesUnsorted = for (i <- 1 to ops.size) yield try {
-        requester.expectMsgType[OperationReply]
-      } catch {
-        case ex: Throwable if ops.size > 10 => sys.error(s"failure to receive confirmation $i/${ops.size}\n$ex")
-        case ex: Throwable                  => sys.error(s"failure to receive confirmation $i/${ops.size}\nRequests:" + ops.mkString("\n    ", "\n     ", "") + s"\n$ex")
-      }
-      val replies = repliesUnsorted.sortBy(_.id)
-      if (replies != expectedReplies) {
-        val pairs = (replies zip expectedReplies).zipWithIndex filter (x => x._1._1 != x._1._2)
-        fail("unexpected replies:" + pairs.map(x => s"at index ${x._2}: got ${x._1._1}, expected ${x._1._2}").mkString("\n    ", "\n    ", ""))
-      }
-    }
-
-  def verify(probe: TestProbe, ops: Seq[Operation], expected: Seq[OperationReply]): Unit = {
-    val topNode = system.actorOf(Props[BinaryTreeSet])
-
-    ops foreach { op =>
-      topNode ! op
-    }
-
-    receiveN(probe, ops, expected)
-    // the grader also verifies that enough actors are created
-  }
-
-  @Test def `proper inserts and lookups (5pts)`(): Unit = {
-    val topNode = system.actorOf(Props[BinaryTreeSet])
-
-    topNode ! Contains(testActor, id = 1, 1)
-    expectMsg(ContainsResult(1, false))
-
-    topNode ! Insert(testActor, id = 2, 1)
-    topNode ! Contains(testActor, id = 3, 1)
-
-    expectMsg(OperationFinished(2))
-    expectMsg(ContainsResult(3, true))
-    ()
-  }
-
-  @Test def `instruction example (5pts)`(): Unit = {
-    val requester = TestProbe()
-    val requesterRef = requester.ref
-    val ops = List(
-      Insert(requesterRef, id=100, 1),
-      Contains(requesterRef, id=50, 2),
-      Remove(requesterRef, id=10, 1),
-      Insert(requesterRef, id=20, 2),
-      Contains(requesterRef, id=80, 1),
-      Contains(requesterRef, id=70, 2)
-    )
-
-    val expectedReplies = List(
-      OperationFinished(id=10),
-      OperationFinished(id=20),
-      ContainsResult(id=50, false),
-      ContainsResult(id=70, true),
-      ContainsResult(id=80, false),
-      OperationFinished(id=100)
-    )
-
-    verify(requester, ops, expectedReplies)
-  }
-
-
-  @Test def `behave identically to built-in set (includes GC) (40pts)`(): Unit = {
-    val rnd = new Random()
-    def randomOperations(requester: ActorRef, count: Int): Seq[Operation] = {
-      def randomElement: Int = rnd.nextInt(100)
-      def randomOperation(requester: ActorRef, id: Int): Operation = rnd.nextInt(4) match {
-        case 0 => Insert(requester, id, randomElement)
-        case 1 => Insert(requester, id, randomElement)
-        case 2 => Contains(requester, id, randomElement)
-        case 3 => Remove(requester, id, randomElement)
-      }
-
-      for (seq <- 0 until count) yield randomOperation(requester, seq)
-    }
-
-    def referenceReplies(operations: Seq[Operation]): Seq[OperationReply] = {
-      var referenceSet = Set.empty[Int]
-      def replyFor(op: Operation): OperationReply = op match {
-        case Insert(_, seq, elem) =>
-          referenceSet = referenceSet + elem
-          OperationFinished(seq)
-        case Remove(_, seq, elem) =>
-          referenceSet = referenceSet - elem
-          OperationFinished(seq)
-        case Contains(_, seq, elem) =>
-          ContainsResult(seq, referenceSet(elem))
-      }
-
-      for (op <- operations) yield replyFor(op)
-    }
-
-    val requester = TestProbe()
-    val topNode = system.actorOf(Props[BinaryTreeSet])
-    val count = 1000
-
-    val ops = randomOperations(requester.ref, count)
-    val expectedReplies = referenceReplies(ops)
-
-    ops foreach { op =>
-      topNode ! op
-      if (rnd.nextDouble() < 0.1) topNode ! GC
-    }
-    receiveN(requester, ops, expectedReplies)
-  }
-}

src/test/scala/example/ListsSuite.scala

@@ -0,0 +1,99 @@
+package example
+
+import org.junit._
+import org.junit.Assert.assertEquals
+
+/**
+ * This class implements a JUnit test suite for the methods in object
+ * `Lists` that need to be implemented as part of this assignment. A test
+ * suite is simply a collection of individual tests for some specific
+ * component of a program.
+ *
+ * To run this test suite, start "sbt" then run the "test" command.
+ */
+class ListsSuite {
+
+  /**
+   * Tests are written using the @Test annotation
+   *
+   * The most common way to implement a test body is using the method `assert`
+   * which tests that its argument evaluates to `true`. So one of the simplest
+   * successful tests is the following:
+   */
+  @Test def `one plus one is two (0pts)`: Unit =
+    assert(1 + 1 == 2)
+
+  @Test def `one plus one is three (0pts)?`: Unit =
+    assert(1 + 1 != 3) // This assertion fails! Go ahead and fix it.
+
+  /**
+   * One problem with the previous (failing) test is that JUnit will
+   * only tell you that a test failed, but it will not tell you what was
+   * the reason for the failure. The output looks like this:
+   *
+   * {{{
+   *    [info] - one plus one is three? *** FAILED ***
+   * }}}
+   *
+   * This situation can be improved by using a Assert.assertEquals
+   * (this is only possible in JUnit). So if you
+   * run the next test, JUnit will show the following output:
+   *
+   * {{{
+   *    [info] - details why one plus one is not three *** FAILED ***
+   *    [info]   2 did not equal 3 (ListsSuite.scala:67)
+   * }}}
+   *
+   * We recommend to always use the Assert.assertEquals equality operator
+   * when writing tests.
+   */
+  @Test def `details why one plus one is not three (0pts)`: Unit =
+    Assert.assertEquals(2, 1 + 1) // Fix me, please!
+
+  /**
+   * Exceptional behavior of a methods can be tested using a try/catch
+   * and a failed assertion.
+   *
+   * In the following example, we test the fact that the method `intNotZero`
+   * throws an `IllegalArgumentException` if its argument is `0`.
+   */
+   @Test def `intNotZero throws an exception if its argument is 0`: Unit =
+     try
+       intNotZero(0)
+       Assert.fail("No exception has been thrown")
+     catch
+       case e: IllegalArgumentException => ()
+
+   def intNotZero(x: Int): Int =
+     if x == 0 then throw new IllegalArgumentException("zero is not allowed")
+     else x
+
+  /**
+   * Now we finally write some tests for the list functions that have to be
+   * implemented for this assignment. We fist import all members of the
+   * `List` object.
+   */
+  import Lists._
+
+
+  /**
+   * We only provide two very basic tests for you. Write more tests to make
+   * sure your `sum` and `max` methods work as expected.
+   *
+   * In particular, write tests for corner cases: negative numbers, zeros,
+   * empty lists, lists with repeated elements, etc.
+   *
+   * It is allowed to have multiple `assert` statements inside one test,
+   * however it is recommended to write an individual `test` statement for
+   * every tested aspect of a method.
+   */
+  @Test def `sum of a few numbers (10pts)`: Unit =
+    assert(sum(List(1,2,0)) == 3)
+
+  @Test def `max of a few numbers (10pts)`: Unit =
+    assert(max(List(3, 7, 2)) == 7)
+
+
+
+  @Rule def individualTestTimeout = new org.junit.rules.Timeout(1000)
+}