Working to refactor

BowlingGame/src/main/scala/Game.scala

@@ -0,0 +1,39 @@
+class Game {
+  var rolls: List[Int] = List()
+
+  def roll(pins: Int): Unit = {
+    if (rolls.length >= 20) {
+      throw new IllegalArgumentException()
+    }
+    rolls = rolls :+ pins
+    if (pins == 10 && rolls.length % 2 == 1) {
+      rolls = rolls :+ 0
+    }
+  }
+
+  private def isStrike(index: Int): Boolean = {
+    if (index <= 2) {
+      return false
+    }
+
+    val even = index % 2 == 0
+    val shouldFirstRollBeDoubled = even && rolls(index-2) == 10
+    val shouldSecondRollBeDoubled = rolls(index-3) == 10
+    shouldFirstRollBeDoubled || shouldSecondRollBeDoubled
+  }
+
+  def score(): Int = {
+    var res = 0
+    for (i <- rolls.indices) {
+      res += rolls(i)
+      val even = i % 2 == 0
+      if (isStrike(i)) {
+        res += rolls(i)
+      }
+      if (even && i > 0 && rolls(i-1) + rolls(i-2) == 10) {
+        res += rolls(i)
+      }
+    }
+    res
+  }
+}

BowlingGame/src/test/scala/GameSpec.scala

@@ -0,0 +1,80 @@
+import org.scalatest._
+import flatspec._
+import matchers._
+
+class GameSpec extends AnyFlatSpec with should.Matchers {
+  "beginning of game" should "return score of 0 " in {
+    val game = new Game()
+    val result  = game.score()
+    result should be(0)
+  }
+
+  "game after one roll of 1" should "return a score of 1" in {
+    val game = new Game()
+    game.roll(1)
+
+    val result = game.score()
+    result should be(1)
+  }
+
+  "full game" should "have 10 frames" in {
+    val game = new Game()
+    for (i <- 0 until 20) {
+      game.roll(1);
+    }
+    val result = game.score()
+    result should be(20)
+  }
+
+  "full game" should "not have more than 10 frames" in {
+    val game = new Game()
+    for (i <- 0 until 20) {
+      game.roll(1);
+    }
+    assertThrows[IllegalArgumentException] {
+      game.roll(1)
+    }
+  }
+
+  "a spare" should "compute the score properly" in {
+    val game = new Game()
+    game.roll(7)
+    game.roll(3)
+    game.roll(4)
+
+    game.score() should be (18)
+  }
+
+  "a game" should "compute the double the next roll after a spare" in {
+    val game = new Game()
+    game.roll(7)
+    game.roll(3)
+    game.roll(7)
+    game.roll(1)
+
+    game.score() should be (25)
+  }
+
+  "a game" should "compute a strike" in {
+    val game = new Game()
+    game.roll(10)
+    game.roll(3)
+    game.roll(4)
+
+    game.score() should be (24)
+  }
+
+  "a game" should "compute a 0-10 spare" in {
+    val game = new Game()
+    game.roll(0)
+    game.roll(10)
+    game.roll(3)
+    game.roll(4)
+
+    game.score() should be (20)
+  }
+
+
+
+
+}