Merge branch 'master' into scala-355

# Conflicts:
#	build.sbt

Author: Matteo Di Pirro

build.sbt

@@ -205,8 +205,10 @@ lazy val scala_akka = (project in file("scala-akka"))
 
 lazy val scala_akka_2 = (project in file("scala-akka-2"))
   .enablePlugins(AkkaGrpcPlugin)
+  .configs(IntegrationTest)
   .settings(
     name := "scala-akka-2",
+    Defaults.itSettings,
     libraryDependencies ++= Seq(
       "com.typesafe.akka" %% "akka-actor-typed" % AkkaVersion,
       "com.typesafe.akka" %% "akka-stream" % AkkaVersion,
@@ -216,10 +218,10 @@ lazy val scala_akka_2 = (project in file("scala-akka-2"))
       "com.typesafe.akka" %% "akka-http-testkit" % AkkaHttpVersion,
       "com.lightbend.akka" %% "akka-stream-alpakka-sse" % "5.0.0",
       "com.typesafe.akka" %% "akka-persistence-typed" % AkkaVersion,
-      "com.typesafe.akka" %% "akka-actor-testkit-typed" % AkkaVersion % Test,
-      "com.typesafe.akka" %% "akka-http-testkit" % AkkaHttpVersion % Test,
-      "com.typesafe.akka" %% "akka-stream-testkit" % AkkaVersion % Test
-    ) ++ scalaTestDeps
+      "com.typesafe.akka" %% "akka-actor-testkit-typed" % AkkaVersion % "it,test",
+      "com.typesafe.akka" %% "akka-http-testkit" % AkkaHttpVersion % "it,test",
+"com.typesafe.akka" %% "akka-stream-testkit" % AkkaVersion % Test
+    ) ++ scalaTestDeps.map(_.withConfigurations(Some("it,test")))
   )
 val monocleVersion = "2.1.0"
 val slickVersion = "3.4.1"

play-scala/README.md

@@ -6,3 +6,4 @@
 - [Caching in Play Framework for Scala](https://www.baeldung.com/scala/play-caching)
 - [Error Handling in the Play Framework Using Scala](https://www.baeldung.com/scala/play-error-handling)
 - [Dependency Injection with Play](https://www.baeldung.com/scala/play-di)
+- [Testing a Play Application](https://www.baeldung.com/scala/scalatest-play-app)

scala-akka-2/src/test/scala-2/com/baeldung/scala/akka_2/alpakka_sse/WikimediaSSEConsumerTest.scala renamed to scala-akka-2/src/it/scala-2/com/baeldung/scala/akka_2/alpakka_sse/WikimediaSSEConsumerLiveTest.scala

@@ -5,7 +5,7 @@ import akka.testkit.TestKit
 import org.scalatest.BeforeAndAfterAll
 import org.scalatest.wordspec.AsyncWordSpecLike
 
-class WikimediaSSEConsumerTest
+class WikimediaSSEConsumerLiveTest
   extends TestKit(ActorSystem("wikimediaSSESpec"))
   with AsyncWordSpecLike
   with BeforeAndAfterAll {

scala-core-8/src/test/scala/com/baeldung/scala/highorderfunctions/HighOrderFunctionsUnitTest.scala

@@ -0,0 +1,96 @@
+package com.baeldung.scala.highorderfunctions
+
+import org.scalatest.flatspec.AnyFlatSpec
+import org.scalatest.matchers.should.Matchers
+
+class HighOrderFunctionsUnitTest extends AnyFlatSpec with Matchers {
+
+  "reduceLeft" should "calculate the sum correctly" in {
+    val numbers = List(1, 2, 3, 4, 5)
+    val actualSum = numbers.reduceLeft(_ + _)
+    // op: 1 + 2 = 3
+    // op: 3 + 3 = 6
+    // op: 6 + 4 = 10
+    // op: 10 + 5 = 15
+    // res: Int = 15
+    assert(15 == actualSum)
+  }
+
+  "reduceLeft" should "concatenate strings correctly" in {
+    val alphabets = List("A", "B", "C", "D", "E")
+    val actualResult = alphabets.reduceLeft(_ + _)
+    assert("ABCDE" == actualResult)
+  }
+
+  "reduceLeft" should "find the largest number correctly" in {
+    val numbers = List(10, 22, 5, 71, 43)
+    val actualResult = numbers.reduceLeft(_ max _)
+    assert(71 == actualResult)
+  }
+
+  "reduceRight" should "calculate the sum correctly" in {
+    val numbers = List(1, 2, 3, 4, 5)
+    val actualSum = numbers.reduceRight(_ + _)
+    // op: 5 + 4 = 9
+    // op: 9 + 3 = 12
+    // op: 12 + 2 = 14
+    // op: 14 + 1 = 15
+    // res: Int = 15
+    assert(15 == actualSum)
+  }
+
+  "foldLeft" should "calculate the sum correctly" in {
+    val numbers = List(1, 2, 3, 4, 5)
+    val actualSum = numbers.foldLeft(5)(_ + _)
+    // op: 5 + 1 = 6
+    // op: 6 + 2 = 8
+    // op: 8 + 3 = 11
+    // op: 11 + 4 = 15
+    // op: 15 + 5 = 20
+    // res: Int = 20
+    assert(20 == actualSum)
+  }
+
+  "foldRight" should "concatenate the strings correctly" in {
+    val alphabets = List("A", "B", "C", "D", "E")
+    val actualResult = alphabets.foldRight("$")(_ + _)
+    // op: E + $ = E$
+    // op: D + E$ = DE$
+    // op: C + DE$ = CDE$
+    // op: B + CDE$ = BCDE$
+    // op: A + BCDE$ = ABCDE$
+    // res: String = ABCDE$
+    assert("ABCDE$" == actualResult)
+  }
+
+  "scanLeft" should "have correct intermediate states" in {
+    val numbers = List(1, 2, 3, 4, 5)
+    val actualResult = numbers.scanLeft(1)(_ + _)
+    assert(List(1, 2, 4, 7, 11, 16) == actualResult)
+  }
+
+  "scanRight" should "have correct intermediate states" in {
+    val numbers = List(1, 2, 3, 4, 5)
+    val actualResult = numbers.scanRight(1)(_ + _)
+    assert(List(16, 15, 13, 10, 6, 1) == actualResult)
+  }
+
+  "reduceLeft" should "throw an exception" in {
+    val numbers = List.empty[Int]
+    assertThrows[UnsupportedOperationException] {
+      numbers.reduceLeft(_ max _)
+    }
+  }
+
+  "foldRight" should "return the initial element i.e $" in {
+    val alphabets = List.empty[String]
+    val actualResult = alphabets.foldRight("$")(_ + _)
+    assert("$" == actualResult)
+  }
+
+  "scanRight" should "return the initial element i.e 5" in {
+    val numbers = List.empty[Int]
+    val actualResult = numbers.scanRight(5)(_ + _)
+    assert(List(5) == actualResult)
+  }
+}

scala-core/build.sbt

@@ -0,0 +1,6 @@
+// Scala 3 configuration
+lazy val Scala3Test = config("scala3Test").extend(Test)
+// Source directories
+scalaSource in Scala3Test := baseDirectory.value / "src" / "main" / "scala-3"
+// Test directories
+scalaSource in Scala3Test := baseDirectory.value / "src" / "test" / "scala-3"

scala-core/src/main/scala-3/com/baeldung/scala/traits/Author.scala

@@ -0,0 +1,5 @@
+package com.baeldung.scala.traits
+
+class Author(name: String) extends Writer(name) {
+  def write(): String = s"$name is writing a book"
+}

scala-core/src/main/scala-3/com/baeldung/scala/traits/MultipleInheritance.scala

@@ -0,0 +1,15 @@
+package com.baeldung.scala.traits
+
+class MultipleInheritance extends Trait1 with Trait2 {
+  override def method1(): String = "Trait1 method"
+
+  override def method2(): String = "Trait2 method"
+}
+
+trait Trait1 {
+  def method1(): String
+}
+
+trait Trait2 {
+  def method2(): String
+}

scala-core/src/main/scala-3/com/baeldung/scala/traits/Poet.scala

@@ -0,0 +1,5 @@
+package com.baeldung.scala.traits
+
+class Poet(name: String) extends Writer(name) {
+  def write(): String = s"$name is composing poetry"
+}

scala-core/src/main/scala-3/com/baeldung/scala/traits/Writer.scala

@@ -0,0 +1,7 @@
+package com.baeldung.scala.traits
+
+trait Writer(val name: String) {
+  def introduce = s"Hello, I'm $name"
+
+  def write(): String
+}

scala-core/src/test/scala-3/com/baeldung/scala/traits/MultipleInheritanceUnitTest.scala

@@ -0,0 +1,14 @@
+package com.baeldung.scala.traits
+
+import org.scalatest.flatspec.AnyFlatSpec
+import org.scalatest.matchers.should.Matchers
+
+class MultipleInheritanceUnitTest extends AnyFlatSpec with Matchers {
+
+  "A class extended from multiple traits" should "have access to all the methods" in {
+    val instance = new MultipleInheritance()
+
+    instance.method1() shouldEqual "Trait1 method"
+    instance.method2() shouldEqual "Trait2 method"
+  }
+}