Remove Scala asInstanceOf usage

BUILD.bazel

@@ -47,3 +47,12 @@ sh_test(
         "no-sandbox",
     ],
 )
+
+sh_test(
+    name = "no_scala_asinstanceof_test",
+    srcs = ["scripts/check_no_scala_asinstanceof.sh"],
+    tags = [
+        "local",
+        "no-sandbox",
+    ],
+)

scripts/check_no_scala_asinstanceof.sh

@@ -0,0 +1,17 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+REPO_ROOT="$(cd "$SCRIPT_DIR/.." && pwd)"
+
+matches="$(
+  grep -R -n "asInstanceOf" \
+    "${REPO_ROOT}/src/main/scala" \
+    "${REPO_ROOT}/src/test/scala" || true
+)"
+
+if [[ -n "${matches}" ]]; then
+  echo "Scala asInstanceOf usage is not allowed:" >&2
+  echo "${matches}" >&2
+  exit 1
+fi

src/main/scala/net/eagle0/common/FunctionalRandom.scala

@@ -163,7 +163,7 @@ abstract class FunctionalRandom {
     @nowarn def foldGen(rsU: RandomState[S[U]], t: T): RandomState[S[U]] =
       rsU.continue {
         case (us: S[U], fr: FunctionalRandom) =>
-          f(t, fr).map(x => (us ++ x).asInstanceOf[S[U]])
+          f(t, fr).map(x => xFactory.from(us ++ x))
       }
     FunctionalRandom.nextFoldLeft(
       seq,
@@ -189,7 +189,7 @@ abstract class FunctionalRandom {
     ): RandomState[S[U]] =
       rsU.continue {
         case (us: S[U], fr: FunctionalRandom) =>
-          f(t, fr).map(x => (us :+ x).asInstanceOf[S[U]])
+          f(t, fr).map(x => xFactory.from(us :+ x))
       }
 
     FunctionalRandom.nextFoldLeft(seq, RandomState(xFactory.empty[U], this))(

src/main/scala/net/eagle0/common/llm_integration/GeminiServiceImpl.scala

@@ -131,7 +131,11 @@ class GeminiServiceImpl(
 
       if candidates.isEmpty then return
 
-      val firstCandidate = candidates.head.asInstanceOf[JObject]
+      val firstCandidate = candidates.head match {
+        case obj: JObject => obj
+        case other        =>
+          throw new IllegalArgumentException(s"Expected Gemini candidate object, got $other")
+      }
 
       // Check finish reason
       val finishReason = (firstCandidate \ "finishReason") match {
@@ -143,17 +147,20 @@ class GeminiServiceImpl(
 
       // Extract text content
       val textContent = for {
-        content <- (firstCandidate \ "content").toOption
-        parts   <- (content \ "parts") match {
-                     case JArray(arr) => Some(arr)
-                     case _           => None
-                   }
+        content   <- (firstCandidate \ "content").toOption
+        parts     <- (content \ "parts") match {
+                       case JArray(arr) => Some(arr)
+                       case _           => None
+                     }
         if parts.nonEmpty
-        firstPart = parts.head.asInstanceOf[JObject]
-        text    <- (firstPart \ "text") match {
-                     case JString(s) => Some(s)
-                     case _          => None
-                   }
+        firstPart <- parts.head match {
+                       case obj: JObject => Some(obj)
+                       case _            => None
+                     }
+        text      <- (firstPart \ "text") match {
+                       case JString(s) => Some(s)
+                       case _          => None
+                     }
       } yield text
 
       val tokenUsage =

src/main/scala/net/eagle0/common/llm_integration/OpenAIChatCompletionsServiceImpl.scala

@@ -120,7 +120,11 @@ class OpenAIChatCompletionsServiceImpl(
     val streamId = (parsedJson \ "id").extract[String]
 
     // The final usage chunk has empty choices array and contains usage info
-    val choicesArray = (parsedJson \ "choices").asInstanceOf[JArray].arr
+    val choicesArray = (parsedJson \ "choices") match {
+      case JArray(arr) => arr
+      case other       =>
+        throw new IllegalArgumentException(s"Expected choices array in OpenAI response, got $other")
+    }
     if choicesArray.isEmpty then {
       // This is the usage-only chunk (when stream_options.include_usage is true)
       val promptTokens     = (parsedJson \ "usage" \ "prompt_tokens").extractOpt[Int].getOrElse(0)
@@ -134,34 +138,37 @@ class OpenAIChatCompletionsServiceImpl(
         )
       )
     } else {
-      val choice = choicesArray.head.asInstanceOf[JObject]
+      choicesArray.head match {
+        case choice: JObject =>
+          // FIXME: this will mark completed if there is any finish_reason; we should probably handle other possibilities
+          val completed = (choice \ "finish_reason") match {
+            case JString("stop")           => true
+            case JString("length")         => true
+            case JString("content_filter") => true
+            case JString("tool_calls")     => true
+            case JString("function_call")  => true
+            case JString(str)              =>
+              println(s"Unexpected finish reason $str")
+              true
+            case _                         => false
+          }
 
-      // FIXME: this will mark completed if there is any finish_reason; we should probably handle other possibilities
-      val completed = (choice \ "finish_reason") match {
-        case JString("stop")           => true
-        case JString("length")         => true
-        case JString("content_filter") => true
-        case JString("tool_calls")     => true
-        case JString("function_call")  => true
-        case JString(str)              =>
-          println(s"Unexpected finish reason $str")
-          true
-        case _                         => false
-      }
-
-      (choice \ "delta" \ "content") match {
-        case JString(contentString) =>
-          streamingConsumer.accept(
-            StreamingTextResults(
-              streamId = streamId,
-              value = contentString,
-              completed = false // Don't mark completed here; wait for usage chunk
-            )
-          )
-        case _                      =>
-          if completed then
-            // Content is done, but don't send final completion yet - wait for usage chunk
-            ()
+          (choice \ "delta" \ "content") match {
+            case JString(contentString) =>
+              streamingConsumer.accept(
+                StreamingTextResults(
+                  streamId = streamId,
+                  value = contentString,
+                  completed = false // Don't mark completed here; wait for usage chunk
+                )
+              )
+            case _                      =>
+              if completed then
+                // Content is done, but don't send final completion yet - wait for usage chunk
+                ()
+          }
+        case other           =>
+          throw new IllegalArgumentException(s"Expected OpenAI choice object, got $other")
       }
     }
   }

src/main/scala/net/eagle0/eagle/auth/JwtService.scala

@@ -145,6 +145,10 @@ object JwtService {
     val keyBytes   = Base64.getDecoder.decode(base64)
     val keySpec    = new X509EncodedKeySpec(keyBytes)
     val keyFactory = KeyFactory.getInstance("RSA")
-    keyFactory.generatePublic(keySpec).asInstanceOf[RSAPublicKey]
+    keyFactory.generatePublic(keySpec) match {
+      case rsaPublicKey: RSAPublicKey => rsaPublicKey
+      case other                      =>
+        throw new IllegalArgumentException(s"Expected RSA public key, got ${other.getClass.getName}")
+    }
   }
 }

src/main/scala/net/eagle0/eagle/auth/OAuthService.scala

@@ -339,7 +339,11 @@ class OAuthServiceImpl(serverBaseUrl: String) extends OAuthService {
         val keyBytes     = Base64.getDecoder.decode(keyLines)
         val keySpec      = new PKCS8EncodedKeySpec(keyBytes)
         val keyFactory   = KeyFactory.getInstance("EC")
-        val ecPrivateKey = keyFactory.generatePrivate(keySpec).asInstanceOf[ECPrivateKey]
+        val ecPrivateKey = keyFactory.generatePrivate(keySpec) match {
+          case privateKey: ECPrivateKey => privateKey
+          case other                    =>
+            throw new IllegalArgumentException(s"Expected EC private key, got ${other.getClass.getName}")
+        }
 
         val now       = Instant.now()
         val expiresAt = now.plusSeconds(15777000) // ~6 months (Apple max)

src/main/scala/net/eagle0/eagle/library/actions/impl/action/PerformReconResolutionAction.scala

@@ -67,7 +67,11 @@ case class PerformReconResolutionAction(
     val targetProvince = gameState.provinces(provinceId)
 
     // Extract heroId from the recon action details
-    val heroId = incomingEndTurnAction.details.asInstanceOf[IncomingRecon].heroId
+    val heroId = incomingEndTurnAction.details match {
+      case recon: IncomingRecon => recon.heroId
+      case null                 =>
+        throw new IllegalArgumentException("Expected incoming recon action details, got null")
+    }
 
     val factionProvinces = gameState.provinces.values.toVector
       .filter(_.rulingFactionId.contains(fromFactionId))

src/main/scala/net/eagle0/eagle/library/util/command_choice_helpers/CommandChoiceHelpers.scala

@@ -505,10 +505,15 @@ object CommandChoiceHelpers {
       reason = reason
     ).filter {
       case CommandSelection(_, _, ac, _, _) =>
+        val restAvailable = ac match {
+          case rest: RestAvailable => rest
+          case other               =>
+            throw new IllegalArgumentException(s"Expected RestAvailable command, got $other")
+        }
         shouldRest(
           gs
             .provinces(
-              ac.asInstanceOf[RestAvailable].actingProvinceId
+              restAvailable.actingProvinceId
             )
             .rulingFactionHeroIds
             .map(gs.heroes)

src/main/scala/net/eagle0/eagle/package.scala

@@ -1,5 +1,7 @@
 package net.eagle0
 
+import scala.reflect.ClassTag
+
 package object eagle {
   type GameId           = Long
   type ShardokGameId    = String
@@ -12,4 +14,10 @@ package object eagle {
   type MovingSuppliesId = Int
 
   type ClientTextId = String
+
+  private[eagle0] def checkedAs[T](value: Any)(using classTag: ClassTag[T]): T =
+    classTag.unapply(value).getOrElse {
+      val actualType = Option(value).map(_.getClass.getName).getOrElse("null")
+      throw new ClassCastException(s"Expected ${classTag.runtimeClass.getName}, got $actualType")
+    }
 }

src/main/scala/net/eagle0/eagle/service/SyncResponseObserver.scala

@@ -8,7 +8,12 @@ class SyncResponseObserver(
     responseObserver: StreamObserver[UpdateStreamResponse]
 ) {
   private val serverCallObserver =
-    responseObserver.asInstanceOf[ServerCallStreamObserver[UpdateStreamResponse]]
+    responseObserver match {
+      case null                                  => null
+      case observer: ServerCallStreamObserver[?] => observer
+      case other                                 =>
+        throw new IllegalArgumentException(s"Expected ServerCallStreamObserver, got ${other.getClass.getName}")
+    }
 
   def isCancelled: Boolean = serverCallObserver.isCancelled
 

src/main/scala/net/eagle0/eagle/service/UnrequestedTextHandler.scala

@@ -85,13 +85,16 @@ class UnrequestedTextHandler(llmResolver: LlmResolver, heroNameCache: HeroNameCa
         withTransaction(clientTextStore) {
           fixedNameRequests.foldLeft((clientTextStore, Vector.empty[ClientText])) {
             case ((cts, completed), ut) =>
+              val fixedName  = ut.llmRequest match {
+                case request: FixedHeroName => request.fixedName
+                case other                  =>
+                  throw new EagleInternalException(s"Expected FixedHeroName request for ${ut.id}, got $other")
+              }
               val withUpdate = cts
                 .withMarkedRequested(ut.id)
                 .withAppendedText(
                   id = ut.id,
-                  newText = ut.llmRequest
-                    .asInstanceOf[FixedHeroName]
-                    .fixedName,
+                  newText = fixedName,
                   complete = true
                 )
               (withUpdate.clientTextStore, completed :+ withUpdate.updatedText)
@@ -114,7 +117,11 @@ class UnrequestedTextHandler(llmResolver: LlmResolver, heroNameCache: HeroNameCa
           heroNameCache
             .takeNames(
               genderStrings = generatedNameRequests.map { ut =>
-                ut.llmRequest.asInstanceOf[GeneratedHeroName].gender
+                ut.llmRequest match {
+                  case request: GeneratedHeroName => request.gender
+                  case other                      =>
+                    throw new EagleInternalException(s"Expected GeneratedHeroName request for ${ut.id}, got $other")
+                }
               }.toVector.map {
                 case Gender.Female  => "female"
                 case Gender.Male    => "male"

src/main/scala/net/eagle0/eagle/service/new_game_creation/TutorialGameCreation.scala

@@ -248,7 +248,11 @@ object TutorialGameCreation {
         val battalionData = attackingArmy.battalions.toVector.map { battalion =>
           val battalionId = nextBattalionId
           nextBattalionId += 1
-          val b           = BattalionConverter.fromProto(battalion).asInstanceOf[BattalionC]
+          val b           = BattalionConverter.fromProto(battalion) match {
+            case battalionC: BattalionC => battalionC
+            case other                  =>
+              throw new IllegalArgumentException(s"Expected BattalionC from tutorial battalion proto, got $other")
+          }
           (battalionId, b.copy(id = battalionId))
         }
 

src/main/scala/net/eagle0/util/HexMapJsonUtils.scala

@@ -75,8 +75,11 @@ object HexMapJsonUtils {
         .map(terrain),
       defenderStartingPositions = Some(
         startingPositions(
-          (obj \ "defenderStartingPositions")
-            .asInstanceOf[JObject]
+          (obj \ "defenderStartingPositions") match {
+            case defenderPositions: JObject => defenderPositions
+            case other                      =>
+              throw new IllegalArgumentException(s"Expected defenderStartingPositions object, got $other")
+          }
         )
       ),
       attackerStartingPositions = (obj \ "attackerStartingPositions").extract[List[JObject]].map { v =>
@@ -86,7 +89,10 @@ object HexMapJsonUtils {
     )
 
   def fromJsonStream(stream: InputStream): HexMap = {
-    val v = parseJson(stringFromStream(stream)).asInstanceOf[JObject]
+    val v = parseJson(stringFromStream(stream)) match {
+      case obj: JObject => obj
+      case other        => throw new IllegalArgumentException(s"Expected hex map JSON object, got $other")
+    }
     mapFromJObject(v)
   }
 

src/test/scala/net/eagle0/eagle/ai/SeekMoreLeadersCommandChooserTest.scala

@@ -1,6 +1,6 @@
 package net.eagle0.eagle.ai
 
-import net.eagle0.eagle.{FactionId, HeroId, ProvinceId}
+import net.eagle0.eagle.{checkedAs, FactionId, HeroId, ProvinceId}
 import net.eagle0.eagle.library.settings.{
   AiMinimumCharismaForSwornBrother,
   AiMinimumConstitutionForSwornBrother,
@@ -276,7 +276,7 @@ class SeekMoreLeadersCommandChooserTest extends AnyFlatSpec with Matchers with B
     val gsAlmostEnoughLoyalty = swearBrotherhoodGameState.copy(
       heroes = swearBrotherhoodGameState.heroes.updated(
         12,
-        swearBrotherhoodGameState.heroes(12).asInstanceOf[HeroC].copy(loyalty = 86)
+        checkedAs[HeroC](swearBrotherhoodGameState.heroes(12)).copy(loyalty = 86)
       )
     )
 
@@ -305,7 +305,7 @@ class SeekMoreLeadersCommandChooserTest extends AnyFlatSpec with Matchers with B
     val gsFeastWontGiveEnough = swearBrotherhoodGameState.copy(
       heroes = swearBrotherhoodGameState.heroes.updated(
         12,
-        swearBrotherhoodGameState.heroes(12).asInstanceOf[HeroC].copy(loyalty = 84)
+        checkedAs[HeroC](swearBrotherhoodGameState.heroes(12)).copy(loyalty = 84)
       )
     )
 
@@ -328,9 +328,9 @@ class SeekMoreLeadersCommandChooserTest extends AnyFlatSpec with Matchers with B
   it should "do nothing if no available hero meets the minimums" in {
     val crappyHeroesGS = swearBrotherhoodGameState.copy(
       heroes = swearBrotherhoodGameState.heroes
-        .updated(12, swearBrotherhoodGameState.heroes(12).asInstanceOf[HeroC].copy(charisma = 64))
-        .updated(9, swearBrotherhoodGameState.heroes(9).asInstanceOf[HeroC].copy(constitution = 63))
-        .updated(13, swearBrotherhoodGameState.heroes(13).asInstanceOf[HeroC].copy(charisma = 60))
+        .updated(12, checkedAs[HeroC](swearBrotherhoodGameState.heroes(12)).copy(charisma = 64))
+        .updated(9, checkedAs[HeroC](swearBrotherhoodGameState.heroes(9)).copy(constitution = 63))
+        .updated(13, checkedAs[HeroC](swearBrotherhoodGameState.heroes(13)).copy(charisma = 60))
     )
 
     SeekMoreLeadersCommandChooser
@@ -354,7 +354,7 @@ class SeekMoreLeadersCommandChooserTest extends AnyFlatSpec with Matchers with B
     val gsWithFewerProvinces = swearBrotherhoodGameState.copy(
       provinces = swearBrotherhoodGameState.provinces.updated(
         20,
-        swearBrotherhoodGameState.provinces(20).asInstanceOf[ProvinceC].copy(rulingFactionId = None)
+        checkedAs[ProvinceC](swearBrotherhoodGameState.provinces(20)).copy(rulingFactionId = None)
       )
     )
 

src/test/scala/net/eagle0/eagle/library/actions/availability/AvailableAttackDecisionCommandFactoryTest.scala

@@ -1,6 +1,6 @@
 package net.eagle0.eagle.library.actions.availability
 
-import net.eagle0.eagle.{FactionId, RoundId}
+import net.eagle0.eagle.{checkedAs, FactionId, RoundId}
 import net.eagle0.eagle.library.settings.{
   MinimumAgilityForArchery,
   MinimumAgilityForStartFire,
@@ -186,18 +186,18 @@ class AvailableAttackDecisionCommandFactoryTest extends AnyFlatSpec with Matcher
   )
 
   private def getAttackDecisionCommand(gs: GameState): AttackDecisionAvailable =
-    AvailableAttackDecisionCommandFactory
-      .availableCommand(gs, attackerFid, defenderProvinceId)
-      .get
-      .asInstanceOf[AttackDecisionAvailable]
+    checkedAs[AttackDecisionAvailable](
+      AvailableAttackDecisionCommandFactory
+        .availableCommand(gs, attackerFid, defenderProvinceId)
+        .get
+    )
 
   private def withTruce(gs: GameState): GameState =
     gs.copy(
       factions = gs.factions
         .updated(
           attackerFid,
-          gs.factions(attackerFid)
-            .asInstanceOf[FactionC]
+          checkedAs[FactionC](gs.factions(attackerFid))
             .copy(
               factionRelationships = Vector(
                 FactionRelationship(
@@ -210,8 +210,7 @@ class AvailableAttackDecisionCommandFactoryTest extends AnyFlatSpec with Matcher
         )
         .updated(
           defenderFid,
-          gs.factions(defenderFid)
-            .asInstanceOf[FactionC]
+          checkedAs[FactionC](gs.factions(defenderFid))
             .copy(
               factionRelationships = Vector(
                 FactionRelationship(
@@ -228,8 +227,7 @@ class AvailableAttackDecisionCommandFactoryTest extends AnyFlatSpec with Matcher
     gs.copy(
       provinces = gs.provinces.updated(
         defenderProvinceId,
-        gs.provinces(defenderProvinceId)
-          .asInstanceOf[ProvinceC]
+        checkedAs[ProvinceC](gs.provinces(defenderProvinceId))
           .copy(
             hostileArmies = Vector(
               gs.provinces(defenderProvinceId)
@@ -265,9 +263,10 @@ class AvailableAttackDecisionCommandFactoryTest extends AnyFlatSpec with Matcher
     val gs = baseGameState.copy(
       provinces = baseGameState.provinces.updated(
         defenderProvinceId,
-        baseGameState
-          .provinces(defenderProvinceId)
-          .asInstanceOf[ProvinceC]
+        checkedAs[ProvinceC](
+          baseGameState
+            .provinces(defenderProvinceId)
+        )
           .copy(
             hostileArmies = Vector(
               baseGameState.provinces(defenderProvinceId).hostileArmies.head.copy(factionId = 5)
@@ -283,9 +282,10 @@ class AvailableAttackDecisionCommandFactoryTest extends AnyFlatSpec with Matcher
     val gs = baseGameState.copy(
       provinces = baseGameState.provinces.updated(
         defenderProvinceId,
-        baseGameState
-          .provinces(defenderProvinceId)
-          .asInstanceOf[ProvinceC]
+        checkedAs[ProvinceC](
+          baseGameState
+            .provinces(defenderProvinceId)
+        )
           .copy(
             hostileArmies = Vector(
               baseGameState
@@ -335,9 +335,10 @@ class AvailableAttackDecisionCommandFactoryTest extends AnyFlatSpec with Matcher
     val gs = baseGameState.copy(
       provinces = baseGameState.provinces.updated(
         defenderProvinceId,
-        baseGameState
-          .provinces(defenderProvinceId)
-          .asInstanceOf[ProvinceC]
+        checkedAs[ProvinceC](
+          baseGameState
+            .provinces(defenderProvinceId)
+        )
           .copy(
             battalionIds = Vector(50, 60, 70, 100, 110, 120)
           )
@@ -388,9 +389,10 @@ class AvailableAttackDecisionCommandFactoryTest extends AnyFlatSpec with Matcher
     val gs = baseGameState.copy(
       provinces = baseGameState.provinces.updated(
         defenderProvinceId,
-        baseGameState
-          .provinces(defenderProvinceId)
-          .asInstanceOf[ProvinceC]
+        checkedAs[ProvinceC](
+          baseGameState
+            .provinces(defenderProvinceId)
+        )
           .copy(
             battalionIds = Vector(50, 60)
           )
@@ -464,9 +466,10 @@ class AvailableAttackDecisionCommandFactoryTest extends AnyFlatSpec with Matcher
       heroes = baseGameState.heroes + (9382        -> HeroC(id = 9382, factionId = Some(anotherAttackerFid))),
       provinces = baseGameState.provinces.updated(
         defenderProvinceId,
-        baseGameState
-          .provinces(defenderProvinceId)
-          .asInstanceOf[ProvinceC]
+        checkedAs[ProvinceC](
+          baseGameState
+            .provinces(defenderProvinceId)
+        )
           .copy(
             hostileArmies = baseGameState.provinces(defenderProvinceId).hostileArmies :+ HostileArmyGroup(
               factionId = anotherAttackerFid,
@@ -486,9 +489,10 @@ class AvailableAttackDecisionCommandFactoryTest extends AnyFlatSpec with Matcher
       factions = baseGameState.factions
         .updated(
           attackerFid,
-          baseGameState
-            .factions(attackerFid)
-            .asInstanceOf[FactionC]
+          checkedAs[FactionC](
+            baseGameState
+              .factions(attackerFid)
+          )
             .copy(
               factionRelationships = Vector(
                 FactionRelationship(
@@ -532,9 +536,10 @@ class AvailableAttackDecisionCommandFactoryTest extends AnyFlatSpec with Matcher
       heroes = baseGameState.heroes + (9382        -> HeroC(id = 9382, factionId = Some(anotherAttackerFid))),
       provinces = baseGameState.provinces.updated(
         defenderProvinceId,
-        baseGameState
-          .provinces(defenderProvinceId)
-          .asInstanceOf[ProvinceC]
+        checkedAs[ProvinceC](
+          baseGameState
+            .provinces(defenderProvinceId)
+        )
           .copy(
             hostileArmies = baseGameState.provinces(defenderProvinceId).hostileArmies :+ HostileArmyGroup(
               factionId = anotherAttackerFid,
@@ -577,9 +582,10 @@ class AvailableAttackDecisionCommandFactoryTest extends AnyFlatSpec with Matcher
       heroes = baseGameState.heroes + (9382           -> HeroC(id = 9382, factionId = Some(hostileFid))),
       provinces = baseGameState.provinces.updated(
         defenderProvinceId,
-        baseGameState
-          .provinces(defenderProvinceId)
-          .asInstanceOf[ProvinceC]
+        checkedAs[ProvinceC](
+          baseGameState
+            .provinces(defenderProvinceId)
+        )
           .copy(
             hostileArmies = Vector(
               baseGameState.provinces(defenderProvinceId).hostileArmies.head,
@@ -625,9 +631,10 @@ class AvailableAttackDecisionCommandFactoryTest extends AnyFlatSpec with Matcher
       heroes = baseGameState.heroes + (9382           -> HeroC(id = 9382, factionId = Some(hostileFid))),
       provinces = baseGameState.provinces.updated(
         defenderProvinceId,
-        baseGameState
-          .provinces(defenderProvinceId)
-          .asInstanceOf[ProvinceC]
+        checkedAs[ProvinceC](
+          baseGameState
+            .provinces(defenderProvinceId)
+        )
           .copy(
             hostileArmies = Vector(
               baseGameState
@@ -673,9 +680,10 @@ class AvailableAttackDecisionCommandFactoryTest extends AnyFlatSpec with Matcher
       heroes = baseGameState.heroes + (9382        -> HeroC(id = 9382, factionId = Some(alliedFid))),
       provinces = baseGameState.provinces.updated(
         defenderProvinceId,
-        baseGameState
-          .provinces(defenderProvinceId)
-          .asInstanceOf[ProvinceC]
+        checkedAs[ProvinceC](
+          baseGameState
+            .provinces(defenderProvinceId)
+        )
           .copy(
             hostileArmies = Vector(
               baseGameState
@@ -704,9 +712,10 @@ class AvailableAttackDecisionCommandFactoryTest extends AnyFlatSpec with Matcher
       factions = baseGameState.factions
         .updated(
           attackerFid,
-          baseGameState
-            .factions(attackerFid)
-            .asInstanceOf[FactionC]
+          checkedAs[FactionC](
+            baseGameState
+              .factions(attackerFid)
+          )
             .copy(
               factionRelationships = Vector(
                 FactionRelationship(
@@ -748,9 +757,10 @@ class AvailableAttackDecisionCommandFactoryTest extends AnyFlatSpec with Matcher
         + (9384        -> HeroC(id = 9384, factionId = Some(joinerFid))),
       provinces = baseGameState.provinces.updated(
         defenderProvinceId,
-        baseGameState
-          .provinces(defenderProvinceId)
-          .asInstanceOf[ProvinceC]
+        checkedAs[ProvinceC](
+          baseGameState
+            .provinces(defenderProvinceId)
+        )
           .copy(
             hostileArmies = Vector(
               HostileArmyGroup(
@@ -840,7 +850,7 @@ class AvailableAttackDecisionCommandFactoryTest extends AnyFlatSpec with Matcher
     val gs = baseGameState.copy(
       provinces = baseGameState.provinces.updated(
         defenderProvinceId,
-        baseGameState.provinces(defenderProvinceId).asInstanceOf[ProvinceC].copy(food = 0, gold = 0)
+        checkedAs[ProvinceC](baseGameState.provinces(defenderProvinceId)).copy(food = 0, gold = 0)
       )
     )
 
@@ -884,9 +894,10 @@ class AvailableAttackDecisionCommandFactoryTest extends AnyFlatSpec with Matcher
       provinces = withTruce(withNoFleeProvince(baseGameState)).provinces
         .updated(
           defenderProvinceId,
-          withTruce(withNoFleeProvince(baseGameState))
-            .provinces(defenderProvinceId)
-            .asInstanceOf[ProvinceC]
+          checkedAs[ProvinceC](
+            withTruce(withNoFleeProvince(baseGameState))
+              .provinces(defenderProvinceId)
+          )
             .copy(
               neighbors = Vector(
                 Neighbor(provinceId = 18, startingPositionIndex = 0),
@@ -917,9 +928,10 @@ class AvailableAttackDecisionCommandFactoryTest extends AnyFlatSpec with Matcher
       provinces = withTruce(withNoFleeProvince(baseGameState)).provinces
         .updated(
           defenderProvinceId,
-          withTruce(withNoFleeProvince(baseGameState))
-            .provinces(defenderProvinceId)
-            .asInstanceOf[ProvinceC]
+          checkedAs[ProvinceC](
+            withTruce(withNoFleeProvince(baseGameState))
+              .provinces(defenderProvinceId)
+          )
             .copy(
               neighbors = Vector(
                 Neighbor(provinceId = 18, startingPositionIndex = 0),

src/test/scala/net/eagle0/eagle/library/actions/availability/AvailableDefendCommandsFactoryTest.scala

@@ -1,6 +1,6 @@
 package net.eagle0.eagle.library.actions.availability
 
-import net.eagle0.eagle.{FactionId, ProvinceId, RoundId}
+import net.eagle0.eagle.{checkedAs, FactionId, ProvinceId, RoundId}
 import net.eagle0.eagle.library.settings.{MaxCombatUnitCountPerSide, MinVigorForDefend}
 import net.eagle0.eagle.model.state.{
   Army,
@@ -194,7 +194,7 @@ class AvailableDefendCommandsFactoryTest extends AnyFlatSpec with BeforeAndAfter
     )
 
     command.get shouldBe a[DefendAvailable]
-    command.get.asInstanceOf[DefendAvailable].actingProvinceId shouldBe defendingProvince.id
+    checkedAs[DefendAvailable](command.get).actingProvinceId shouldBe defendingProvince.id
   }
 
   it should "include heroes with sufficient vigor" in {
@@ -205,7 +205,7 @@ class AvailableDefendCommandsFactoryTest extends AnyFlatSpec with BeforeAndAfter
       7
     )
 
-    command.get.asInstanceOf[DefendAvailable].availableHeroIds should contain theSameElementsAs sufficientVigorHeroes
+    checkedAs[DefendAvailable](command.get).availableHeroIds should contain theSameElementsAs sufficientVigorHeroes
       .map(_.id)
   }
 
@@ -217,7 +217,7 @@ class AvailableDefendCommandsFactoryTest extends AnyFlatSpec with BeforeAndAfter
       7
     )
 
-    command.get.asInstanceOf[DefendAvailable].availableHeroIds should contain.noneOf(3, 4)
+    checkedAs[DefendAvailable](command.get).availableHeroIds should contain.noneOf(3, 4)
   }
 
   it should "include all battalions" in {
@@ -228,9 +228,7 @@ class AvailableDefendCommandsFactoryTest extends AnyFlatSpec with BeforeAndAfter
       7
     )
 
-    command.get
-      .asInstanceOf[DefendAvailable]
-      .availableBattalions
+    checkedAs[DefendAvailable](command.get).availableBattalions
       .map(_.battalionId) should contain theSameElementsAs (validBattalions ++ invalidBattalions)
       .map(_.id)
   }
@@ -272,7 +270,7 @@ class AvailableDefendCommandsFactoryTest extends AnyFlatSpec with BeforeAndAfter
       7
     )
 
-    command.get.asInstanceOf[DefendAvailable].availableFleeProvinceIds shouldBe Vector(
+    checkedAs[DefendAvailable](command.get).availableFleeProvinceIds shouldBe Vector(
       9, // own province
       8, // empty province
       4, // attacker
@@ -299,19 +297,20 @@ class AvailableDefendCommandsFactoryTest extends AnyFlatSpec with BeforeAndAfter
       7
     )
 
-    command.get.asInstanceOf[DefendAvailable].availableFleeProvinceIds shouldBe empty
+    checkedAs[DefendAvailable](command.get).availableFleeProvinceIds shouldBe empty
   }
 
   it should "include the info about the attacking armies" in {
     val gameState = makeGameState(Map(7 -> defendingProvince.copy(hostileArmies = Vector(attackingArmy))))
-    val command   = AvailableDefendCommandsFactory
-      .availableCommand(
-        gameState,
-        actingFactionId,
-        7
-      )
-      .get
-      .asInstanceOf[DefendAvailable]
+    val command   = checkedAs[DefendAvailable](
+      AvailableDefendCommandsFactory
+        .availableCommand(
+          gameState,
+          actingFactionId,
+          7
+        )
+        .get
+    )
 
     command.hostileFactionIds shouldBe Vector(attackingFid)
     command.hostileHeroCount shouldBe 3

src/test/scala/net/eagle0/eagle/library/actions/availability/AvailableHandleCapturedHeroCommandFactoryTest.scala

@@ -1,6 +1,6 @@
 package net.eagle0.eagle.library.actions.availability
 
-import net.eagle0.eagle.{FactionId, ProvinceId}
+import net.eagle0.eagle.{checkedAs, FactionId, ProvinceId}
 import net.eagle0.eagle.library.settings.{
   MinimumAgilityForArchery,
   MinimumAgilityForStartFire,
@@ -102,9 +102,10 @@ class AvailableHandleCapturedHeroCommandFactoryTest
   private val gameStateWithOne: GameState = gameStateWithTwo.copy(
     provinces = gameStateWithTwo.provinces.updated(
       provinceId,
-      gameStateWithTwo
-        .provinces(provinceId)
-        .asInstanceOf[ProvinceC]
+      checkedAs[ProvinceC](
+        gameStateWithTwo
+          .provinces(provinceId)
+      )
         .copy(
           capturedHeroes = gameStateWithTwo.provinces(provinceId).capturedHeroes.drop(1)
         )
@@ -112,10 +113,11 @@ class AvailableHandleCapturedHeroCommandFactoryTest
   )
 
   private def getHandleCapturedHeroCommand(gs: GameState): HandleCapturedHeroAvailable =
-    AvailableHandleCapturedHeroCommandFactory
-      .availableCommand(gs, factionId = rulingFactionId, provinceId = provinceId)
-      .get
-      .asInstanceOf[HandleCapturedHeroAvailable]
+    checkedAs[HandleCapturedHeroAvailable](
+      AvailableHandleCapturedHeroCommandFactory
+        .availableCommand(gs, factionId = rulingFactionId, provinceId = provinceId)
+        .get
+    )
 
   "availableCommand" should "set the basics" in {
     val cmd = getHandleCapturedHeroCommand(gameStateWithTwo)
@@ -240,9 +242,10 @@ class AvailableHandleCapturedHeroCommandFactoryTest
       ),
       provinces = gameStateWithOne.provinces.updated(
         5,
-        gameStateWithOne
-          .provinces(5)
-          .asInstanceOf[ProvinceC]
+        checkedAs[ProvinceC](
+          gameStateWithOne
+            .provinces(5)
+        )
           .copy(
             rulingFactionId = None
           )

src/test/scala/net/eagle0/eagle/library/actions/availability/AvailableManagePrisonerCommandsFactoryTest.scala

@@ -1,6 +1,6 @@
 package net.eagle0.eagle.library.actions.availability
 
-import net.eagle0.eagle.{FactionId, HeroId, ProvinceId}
+import net.eagle0.eagle.{checkedAs, FactionId, HeroId, ProvinceId}
 import net.eagle0.eagle.library.settings.{MinimumAgilityForArchery, MinimumAgilityForStartFire}
 import net.eagle0.eagle.model.state.{GameType, RoundPhase}
 import net.eagle0.eagle.model.state.command.available.AvailableCommand.ManagePrisonersAvailable
@@ -115,10 +115,11 @@ class AvailableManagePrisonerCommandsFactoryTest extends AnyFlatSpec with Before
   )
 
   private def getManagePrisonersCommand(gs: GameState): ManagePrisonersAvailable =
-    AvailableManagePrisonersCommandFactory
-      .availableCommand(gs, actingFactionId, actingProvinceId)
-      .get
-      .asInstanceOf[ManagePrisonersAvailable]
+    checkedAs[ManagePrisonersAvailable](
+      AvailableManagePrisonersCommandFactory
+        .availableCommand(gs, actingFactionId, actingProvinceId)
+        .get
+    )
 
   "availableCommand" should "return a command with all the prisoners" in {
     val ac = getManagePrisonersCommand(baseGameState)
@@ -195,9 +196,10 @@ class AvailableManagePrisonerCommandsFactoryTest extends AnyFlatSpec with Before
     val gs = baseGameState.copy(
       provinces = baseGameState.provinces.updated(
         neighbor1ProvinceId,
-        baseGameState
-          .provinces(neighbor1ProvinceId)
-          .asInstanceOf[ProvinceC]
+        checkedAs[ProvinceC](
+          baseGameState
+            .provinces(neighbor1ProvinceId)
+        )
           .copy(
             rulingFactionId = Some(actingFactionId)
           )
@@ -218,18 +220,20 @@ class AvailableManagePrisonerCommandsFactoryTest extends AnyFlatSpec with Before
       provinces = baseGameState.provinces
         .updated(
           neighbor1ProvinceId,
-          baseGameState
-            .provinces(neighbor1ProvinceId)
-            .asInstanceOf[ProvinceC]
+          checkedAs[ProvinceC](
+            baseGameState
+              .provinces(neighbor1ProvinceId)
+          )
             .copy(
               rulingFactionId = Some(actingFactionId)
             )
         )
         .updated(
           neighbor2ProvinceId,
-          baseGameState
-            .provinces(neighbor2ProvinceId)
-            .asInstanceOf[ProvinceC]
+          checkedAs[ProvinceC](
+            baseGameState
+              .provinces(neighbor2ProvinceId)
+          )
             .copy(
               rulingFactionId = Some(actingFactionId)
             )
@@ -250,9 +254,10 @@ class AvailableManagePrisonerCommandsFactoryTest extends AnyFlatSpec with Before
     val gsWithNoPrisoners = baseGameState.copy(
       provinces = baseGameState.provinces.updated(
         actingProvinceId,
-        baseGameState
-          .provinces(actingProvinceId)
-          .asInstanceOf[ProvinceC]
+        checkedAs[ProvinceC](
+          baseGameState
+            .provinces(actingProvinceId)
+        )
           .copy(
             unaffiliatedHeroes = baseGameState
               .provinces(actingProvinceId)
@@ -270,9 +275,10 @@ class AvailableManagePrisonerCommandsFactoryTest extends AnyFlatSpec with Before
     val gsNotTraveling = baseGameState.copy(
       provinces = baseGameState.provinces.updated(
         actingProvinceId,
-        baseGameState
-          .provinces(actingProvinceId)
-          .asInstanceOf[ProvinceC]
+        checkedAs[ProvinceC](
+          baseGameState
+            .provinces(actingProvinceId)
+        )
           .copy(
             rulerIsTraveling = false
           )

src/test/scala/net/eagle0/eagle/library/actions/availability/AvailableResolveBreakAllianceCommandFactoryTest.scala

@@ -94,53 +94,58 @@ class AvailableResolveBreakAllianceCommandFactoryTest extends AnyFlatSpec with M
 
     inside(cmd) {
       case AvailableCommand.ResolveBreakAllianceAvailable(offers) =>
-        offers should have size 2
-        offers should contain(
-          DiplomacyOfferInfo(
-            offeringFactionId = secondOfferingFid,
-            targetFactionId = actingFid,
-            heroId = Some(54),
-            eligibleStatuses = Vector(Accepted, Imprisoned)
+        offers.should(have size 2)
+        offers.should(
+          contain(
+            DiplomacyOfferInfo(
+              offeringFactionId = secondOfferingFid,
+              targetFactionId = actingFid,
+              heroId = Some(54),
+              eligibleStatuses = Vector(Accepted, Imprisoned)
+            )
           )
         )
-        offers should contain(
-          DiplomacyOfferInfo(
-            offeringFactionId = firstOfferingFid,
-            targetFactionId = actingFid,
-            heroId = Some(53),
-            eligibleStatuses = Vector(Accepted, Imprisoned)
+        offers.should(
+          contain(
+            DiplomacyOfferInfo(
+              offeringFactionId = firstOfferingFid,
+              targetFactionId = actingFid,
+              heroId = Some(53),
+              eligibleStatuses = Vector(Accepted, Imprisoned)
+            )
           )
         )
     }
   }
 
   it should "not include alliances that have already been resolved" in {
+    val actingFaction = gameState.factions(actingFid) match {
+      case faction: FactionC => faction
+    }
+
     val gsWithOneResolved = gameState.copy(
       factions = gameState.factions.updated(
         actingFid,
-        gameState
-          .factions(actingFid)
-          .asInstanceOf[FactionC]
-          .copy(
-            incomingDiplomacyOffers = Vector(
-              BreakAlliance(
-                originatingFactionId = firstOfferingFid,
-                targetFactionId = actingFid,
-                messengerHeroId = 53,
-                messengerOriginProvinceId = 19,
-                status = Rejected,
-                offerTextId = "break alliance offer"
-              ),
-              BreakAlliance(
-                originatingFactionId = secondOfferingFid,
-                targetFactionId = actingFid,
-                messengerHeroId = 54,
-                messengerOriginProvinceId = 20,
-                status = Unresolved,
-                offerTextId = "break alliance offer 2"
-              )
+        actingFaction.copy(
+          incomingDiplomacyOffers = Vector(
+            BreakAlliance(
+              originatingFactionId = firstOfferingFid,
+              targetFactionId = actingFid,
+              messengerHeroId = 53,
+              messengerOriginProvinceId = 19,
+              status = Rejected,
+              offerTextId = "break alliance offer"
+            ),
+            BreakAlliance(
+              originatingFactionId = secondOfferingFid,
+              targetFactionId = actingFid,
+              messengerHeroId = 54,
+              messengerOriginProvinceId = 20,
+              status = Unresolved,
+              offerTextId = "break alliance offer 2"
             )
           )
+        )
       )
     )
 
@@ -150,12 +155,14 @@ class AvailableResolveBreakAllianceCommandFactoryTest extends AnyFlatSpec with M
 
     inside(cmd) {
       case AvailableCommand.ResolveBreakAllianceAvailable(offers) =>
-        offers should have size 1
-        offers.head shouldBe DiplomacyOfferInfo(
-          offeringFactionId = secondOfferingFid,
-          targetFactionId = actingFid,
-          heroId = Some(54),
-          eligibleStatuses = Vector(Accepted, Imprisoned)
+        offers.should(have size 1)
+        offers.head.shouldBe(
+          DiplomacyOfferInfo(
+            offeringFactionId = secondOfferingFid,
+            targetFactionId = actingFid,
+            heroId = Some(54),
+            eligibleStatuses = Vector(Accepted, Imprisoned)
+          )
         )
     }
   }
@@ -174,17 +181,18 @@ class AvailableResolveBreakAllianceCommandFactoryTest extends AnyFlatSpec with M
 
     inside(cmd) {
       case AvailableCommand.ResolveBreakAllianceAvailable(offers) =>
-        offers should have size 2
+        offers.should(have size 2)
         offers.foreach { offer =>
-          offer.eligibleStatuses shouldBe Vector(Accepted)
+          offer.eligibleStatuses.shouldBe(Vector(Accepted))
         }
     }
   }
 
-  it should "return nothing if there are no break alliance offers" in {
-    AvailableResolveBreakAllianceCommandFactory.availableCommand(
-      gameState,
-      secondOfferingFid
-    ) shouldBe empty
-  }
+  it should "return nothing if there are no break alliance offers" in
+    AvailableResolveBreakAllianceCommandFactory
+      .availableCommand(
+        gameState,
+        secondOfferingFid
+      )
+      .shouldBe(empty)
 }

src/test/scala/net/eagle0/eagle/library/actions/availability/AvailableResolveTributeCommandsFactoryTest.scala

@@ -20,6 +20,7 @@ import net.eagle0.eagle.model.state.GameType
 import net.eagle0.eagle.model.state.HostileArmyGroupStatus.TributeDemanded
 import org.scalatest.flatspec.AnyFlatSpec
 import org.scalatest.matchers.should.Matchers
+import org.scalatest.Inside.inside
 
 class AvailableResolveTributeCommandsFactoryTest extends AnyFlatSpec with Matchers {
   val actingFactionId: FactionId   = 3
@@ -138,29 +139,34 @@ class AvailableResolveTributeCommandsFactoryTest extends AnyFlatSpec with Matche
       )
       .get
 
-    resolveCommand shouldBe a[ResolveTributeAvailable]
-    val tributeCmd = resolveCommand.asInstanceOf[ResolveTributeAvailable]
-    tributeCmd.actingProvinceId shouldBe actingProvinceId
-    tributeCmd.availableFood shouldBe 9898
-    tributeCmd.availableGold shouldBe 3232
-    tributeCmd.demands should have size 2
-    tributeCmd.demands should contain(
-      TributeAndFaction(
-        demandingFactionId = hostileFaction1Id,
-        goldDemanded = 123,
-        foodDemanded = 456,
-        heroCount = 1,
-        troopCount = 150
-      )
-    )
-    tributeCmd.demands should contain(
-      TributeAndFaction(
-        demandingFactionId = hostileFaction2Id,
-        goldDemanded = 333,
-        foodDemanded = 999,
-        heroCount = 1,
-        troopCount = 2555
-      )
-    )
+    inside(resolveCommand) {
+      case tributeCmd: ResolveTributeAvailable =>
+        tributeCmd.actingProvinceId.shouldBe(actingProvinceId)
+        tributeCmd.availableFood.shouldBe(9898)
+        tributeCmd.availableGold.shouldBe(3232)
+        tributeCmd.demands.size.shouldBe(2)
+        tributeCmd.demands.should(
+          contain(
+            TributeAndFaction(
+              demandingFactionId = hostileFaction1Id,
+              goldDemanded = 123,
+              foodDemanded = 456,
+              heroCount = 1,
+              troopCount = 150
+            )
+          )
+        )
+        tributeCmd.demands.should(
+          contain(
+            TributeAndFaction(
+              demandingFactionId = hostileFaction2Id,
+              goldDemanded = 333,
+              foodDemanded = 999,
+              heroCount = 1,
+              troopCount = 2555
+            )
+          )
+        )
+    }
   }
 }

src/test/scala/net/eagle0/eagle/library/actions/impl/action/EndAttackDecisionPhaseActionTest.scala

@@ -1,6 +1,6 @@
 package net.eagle0.eagle.library.actions.impl.action
 
-import net.eagle0.eagle.{FactionId, GameId, RoundId}
+import net.eagle0.eagle.{checkedAs, FactionId, GameId, RoundId}
 import net.eagle0.eagle.model.action_result.changed_province.concrete.{ChangedProvinceC, HostileArmyStatusChange}
 import net.eagle0.eagle.model.action_result.concrete.NotificationC
 import net.eagle0.eagle.model.action_result.types.ActionResultType.{ArmyShattered, EndAttackDecisionPhase, QuestFailed}
@@ -347,9 +347,7 @@ class EndAttackDecisionPhaseActionTest extends AnyFlatSpec with Matchers {
       ).results
 
     val bounceResults = results.filter { r =>
-      r.changedProvinces.exists { cp =>
-        cp.asInstanceOf[ChangedProvinceC].hostileArmyStatusChanges.nonEmpty
-      }
+      r.changedProvinces.exists(cp => checkedAs[ChangedProvinceC](cp).hostileArmyStatusChanges.nonEmpty)
     }
     bounceResults should have size 1
     inside(bounceResults.head.changedProvinces.head) {
@@ -441,9 +439,7 @@ class EndAttackDecisionPhaseActionTest extends AnyFlatSpec with Matchers {
       ).results
 
     val bounceResults = results.filter { r =>
-      r.changedProvinces.exists { cp =>
-        cp.asInstanceOf[ChangedProvinceC].hostileArmyStatusChanges.nonEmpty
-      }
+      r.changedProvinces.exists(cp => checkedAs[ChangedProvinceC](cp).hostileArmyStatusChanges.nonEmpty)
     }
     bounceResults shouldBe empty
   }
@@ -513,9 +509,7 @@ class EndAttackDecisionPhaseActionTest extends AnyFlatSpec with Matchers {
       ).results
 
     val bounceResults = results.filter { r =>
-      r.changedProvinces.exists { cp =>
-        cp.asInstanceOf[ChangedProvinceC].hostileArmyStatusChanges.nonEmpty
-      }
+      r.changedProvinces.exists(cp => checkedAs[ChangedProvinceC](cp).hostileArmyStatusChanges.nonEmpty)
     }
     bounceResults should have size 1
     inside(bounceResults.head.changedProvinces.head) {
@@ -608,9 +602,7 @@ class EndAttackDecisionPhaseActionTest extends AnyFlatSpec with Matchers {
       ).results
 
     val bounceResults = results.filter { r =>
-      r.changedProvinces.exists { cp =>
-        cp.asInstanceOf[ChangedProvinceC].hostileArmyStatusChanges.nonEmpty
-      }
+      r.changedProvinces.exists(cp => checkedAs[ChangedProvinceC](cp).hostileArmyStatusChanges.nonEmpty)
     }
     bounceResults shouldBe empty
   }

src/test/scala/net/eagle0/eagle/library/actions/impl/action/EndDefenseDecisionPhaseActionTest.scala

@@ -130,42 +130,43 @@ class EndDefenseDecisionPhaseActionTest extends AnyFlatSpec with Matchers {
   it should "remove tribute paid armies from the province" in {
     val actionResult = EndDefenseDecisionPhaseAction(gameState).immediateExecute
 
-    val changedDefendingProvince = actionResult.changedProvinces
-      .find(_.provinceId == defendingProvinceId)
-      .map(_.asInstanceOf[ChangedProvinceC])
-    changedDefendingProvince should not be empty
-    changedDefendingProvince.get.removedHostileArmyFactionIds should contain allOf (attacker1Fid, attacker2Fid)
+    val changedDefendingProvince = actionResult.changedProvinces.collectFirst {
+      case cp: ChangedProvinceC if cp.provinceId == defendingProvinceId => cp
+    }
+    changedDefendingProvince.should(not be empty)
+    changedDefendingProvince.get.removedHostileArmyFactionIds.should(contain(attacker1Fid))
+    changedDefendingProvince.get.removedHostileArmyFactionIds.should(contain(attacker2Fid))
   }
 
   it should "add returning armies to their origin provinces" in {
     val actionResult = EndDefenseDecisionPhaseAction(gameState).immediateExecute
 
     // Province 7 should have incoming army returning
-    val province7Changes = actionResult.changedProvinces
-      .find(_.provinceId == 7)
-      .map(_.asInstanceOf[ChangedProvinceC])
-    province7Changes should not be empty
-    province7Changes.get.newIncomingArmies should have size 1
-    province7Changes.get.newIncomingArmies.head.originProvinceId shouldBe defendingProvinceId
-    province7Changes.get.newIncomingArmies.head.destinationProvinceId shouldBe 7
-    province7Changes.get.newIncomingArmies.head.arrivalRound shouldBe 20
+    val province7Changes = actionResult.changedProvinces.collectFirst {
+      case cp: ChangedProvinceC if cp.provinceId == 7 => cp
+    }
+    province7Changes.should(not be empty)
+    province7Changes.get.newIncomingArmies.size.shouldBe(1)
+    province7Changes.get.newIncomingArmies.head.originProvinceId.shouldBe(defendingProvinceId)
+    province7Changes.get.newIncomingArmies.head.destinationProvinceId.shouldBe(7)
+    province7Changes.get.newIncomingArmies.head.arrivalRound.shouldBe(20)
 
     // Province 27 should have incoming army returning
-    val province27Changes = actionResult.changedProvinces
-      .find(_.provinceId == 27)
-      .map(_.asInstanceOf[ChangedProvinceC])
-    province27Changes should not be empty
-    province27Changes.get.newIncomingArmies should have size 1
-    province27Changes.get.newIncomingArmies.head.originProvinceId shouldBe defendingProvinceId
-    province27Changes.get.newIncomingArmies.head.destinationProvinceId shouldBe 27
+    val province27Changes = actionResult.changedProvinces.collectFirst {
+      case cp: ChangedProvinceC if cp.provinceId == 27 => cp
+    }
+    province27Changes.should(not be empty)
+    province27Changes.get.newIncomingArmies.size.shouldBe(1)
+    province27Changes.get.newIncomingArmies.head.originProvinceId.shouldBe(defendingProvinceId)
+    province27Changes.get.newIncomingArmies.head.destinationProvinceId.shouldBe(27)
 
     // Province 8 should have incoming army returning
-    val province8Changes = actionResult.changedProvinces
-      .find(_.provinceId == 8)
-      .map(_.asInstanceOf[ChangedProvinceC])
-    province8Changes should not be empty
-    province8Changes.get.newIncomingArmies should have size 1
-    province8Changes.get.newIncomingArmies.head.originProvinceId shouldBe defendingProvinceId
-    province8Changes.get.newIncomingArmies.head.destinationProvinceId shouldBe 8
+    val province8Changes = actionResult.changedProvinces.collectFirst {
+      case cp: ChangedProvinceC if cp.provinceId == 8 => cp
+    }
+    province8Changes.should(not be empty)
+    province8Changes.get.newIncomingArmies.size.shouldBe(1)
+    province8Changes.get.newIncomingArmies.head.originProvinceId.shouldBe(defendingProvinceId)
+    province8Changes.get.newIncomingArmies.head.destinationProvinceId.shouldBe(8)
   }
 }

src/test/scala/net/eagle0/eagle/library/actions/impl/action/EndHandleRiotsPhaseActionTest.scala

@@ -1,6 +1,7 @@
 package net.eagle0.eagle.library.actions.impl.action
 
 import net.eagle0.common.SeededRandom
+import net.eagle0.eagle.checkedAs
 import net.eagle0.eagle.library.actions.applier.ActionResultApplierImpl
 import net.eagle0.eagle.library.actions.impl.command.{HandleRiotDoNothingCommand, TCommandFactory}
 import net.eagle0.eagle.library.actions.impl.common.TCommand
@@ -133,7 +134,7 @@ class EndHandleRiotsPhaseActionTest extends AnyFlatSpec with BeforeAndAfterEach
     result.provinceId shouldBe Some(pid)
     result.actingFactionId shouldBe Some(fid)
     result.changedProvinces.should(have.size(1))
-    val changedProvince = result.changedProvinces.head.asInstanceOf[ChangedProvinceC]
+    val changedProvince = checkedAs[ChangedProvinceC](result.changedProvinces.head)
     changedProvince.setHasActed shouldBe Some(true)
     result.actionResultType should (be(RiotAversionFailed) or be(RiotOccurred))
   }

src/test/scala/net/eagle0/eagle/library/actions/impl/action/NewYearActionTest.scala

@@ -1,6 +1,6 @@
 package net.eagle0.eagle.library.actions.impl.action
 
-import net.eagle0.eagle.{HeroId, ProvinceId}
+import net.eagle0.eagle.{checkedAs, HeroId, ProvinceId}
 import net.eagle0.eagle.library.settings.{
   AmbitionFactorForLoyaltyDegradation,
   FoodIncreasePerAgriculture,
@@ -135,10 +135,10 @@ class NewYearActionTest extends AnyFlatSpec with Matchers with BeforeAndAfterEac
   private def gs: GameState = baseGameState
 
   private def updateProvince(gs: GameState, provinceId: ProvinceId)(f: ProvinceC => ProvinceC): GameState =
-    gs.copy(provinces = gs.provinces.updated(provinceId, f(gs.provinces(provinceId).asInstanceOf[ProvinceC])))
+    gs.copy(provinces = gs.provinces.updated(provinceId, f(checkedAs[ProvinceC](gs.provinces(provinceId)))))
 
   private def updateHero(gs: GameState, heroId: HeroId)(f: HeroC => HeroC): GameState =
-    gs.copy(heroes = gs.heroes.updated(heroId, f(gs.heroes(heroId).asInstanceOf[HeroC])))
+    gs.copy(heroes = gs.heroes.updated(heroId, f(checkedAs[HeroC](gs.heroes(heroId)))))
 
   override def beforeEach(): Unit = {
     MinSupportForTaxes.setDoubleValue(45)
@@ -161,7 +161,7 @@ class NewYearActionTest extends AnyFlatSpec with Matchers with BeforeAndAfterEac
     val result = NewYearAction(gs).immediateExecute
 
     val lowSupportAfter =
-      result.changedProvinces.find(_.provinceId == lowSupportProvince.id).get.asInstanceOf[ChangedProvinceC]
+      checkedAs[ChangedProvinceC](result.changedProvinces.find(_.provinceId == lowSupportProvince.id).get)
     lowSupportAfter.foodDelta shouldBe None
     lowSupportAfter.goldDelta shouldBe None
   }
@@ -170,7 +170,7 @@ class NewYearActionTest extends AnyFlatSpec with Matchers with BeforeAndAfterEac
     val result = NewYearAction(gs).immediateExecute
 
     val highSupportAfter =
-      result.changedProvinces.find(_.provinceId == highSupportProvince.id).get.asInstanceOf[ChangedProvinceC]
+      checkedAs[ChangedProvinceC](result.changedProvinces.find(_.provinceId == highSupportProvince.id).get)
     highSupportAfter.goldDelta should contain((40 * highSupportProvince.economy).toInt)
   }
 
@@ -178,7 +178,7 @@ class NewYearActionTest extends AnyFlatSpec with Matchers with BeforeAndAfterEac
     val result = NewYearAction(gs).immediateExecute
 
     val highSupportAfter =
-      result.changedProvinces.find(_.provinceId == highSupportProvince.id).get.asInstanceOf[ChangedProvinceC]
+      checkedAs[ChangedProvinceC](result.changedProvinces.find(_.provinceId == highSupportProvince.id).get)
     highSupportAfter.foodDelta should contain((60 * highSupportProvince.agriculture).toInt)
   }
 
@@ -186,7 +186,7 @@ class NewYearActionTest extends AnyFlatSpec with Matchers with BeforeAndAfterEac
     val result = NewYearAction(gs).immediateExecute
 
     val oldAndNew = provincesMap.values.map(p =>
-      (p, result.changedProvinces.find(_.provinceId == p.id).get.asInstanceOf[ChangedProvinceC])
+      (p, checkedAs[ChangedProvinceC](result.changedProvinces.find(_.provinceId == p.id).get))
     )
 
     for (oldProv, newProv) <- oldAndNew do {
@@ -199,7 +199,7 @@ class NewYearActionTest extends AnyFlatSpec with Matchers with BeforeAndAfterEac
     val result = NewYearAction(gs).immediateExecute
 
     val oldAndNew = provincesMap.values.map(p =>
-      (p, result.changedProvinces.find(_.provinceId == p.id).get.asInstanceOf[ChangedProvinceC])
+      (p, checkedAs[ChangedProvinceC](result.changedProvinces.find(_.provinceId == p.id).get))
     )
 
     for (oldProv, newProv) <- oldAndNew do {
@@ -214,7 +214,7 @@ class NewYearActionTest extends AnyFlatSpec with Matchers with BeforeAndAfterEac
     val result = NewYearAction(gs).immediateExecute
 
     val oldAndNew = provincesMap.values.map(p =>
-      (p, result.changedProvinces.find(_.provinceId == p.id).get.asInstanceOf[ChangedProvinceC])
+      (p, checkedAs[ChangedProvinceC](result.changedProvinces.find(_.provinceId == p.id).get))
     )
 
     for (oldProv, newProv) <- oldAndNew do {
@@ -229,7 +229,7 @@ class NewYearActionTest extends AnyFlatSpec with Matchers with BeforeAndAfterEac
     val result = NewYearAction(gs).immediateExecute
 
     val oldAndNew = provincesMap.values.map(p =>
-      (p, result.changedProvinces.find(_.provinceId == p.id).get.asInstanceOf[ChangedProvinceC])
+      (p, checkedAs[ChangedProvinceC](result.changedProvinces.find(_.provinceId == p.id).get))
     )
 
     for (oldProv, newProv) <- oldAndNew do newProv.supportDelta should contain(-0.15 * oldProv.support)
@@ -239,7 +239,7 @@ class NewYearActionTest extends AnyFlatSpec with Matchers with BeforeAndAfterEac
     val result = NewYearAction(gs).immediateExecute
 
     val oldAndNew =
-      battalions.map(b => (b, result.changedBattalions.find(_.battalionId == b.id).get.asInstanceOf[ChangedBattalionC]))
+      battalions.map(b => (b, checkedAs[ChangedBattalionC](result.changedBattalions.find(_.battalionId == b.id).get)))
 
     for (oldB, newB) <- oldAndNew do newB.to.armament shouldBe (0.85 * oldB.armament)
   }
@@ -248,7 +248,7 @@ class NewYearActionTest extends AnyFlatSpec with Matchers with BeforeAndAfterEac
     val result = NewYearAction(gs).immediateExecute
 
     val oldAndNew =
-      battalions.map(b => (b, result.changedBattalions.find(_.battalionId == b.id).get.asInstanceOf[ChangedBattalionC]))
+      battalions.map(b => (b, checkedAs[ChangedBattalionC](result.changedBattalions.find(_.battalionId == b.id).get)))
 
     for (oldB, newB) <- oldAndNew do newB.to.training shouldBe (0.85 * oldB.training)
   }
@@ -268,7 +268,7 @@ class NewYearActionTest extends AnyFlatSpec with Matchers with BeforeAndAfterEac
 
     val result = NewYearAction(modState).immediateExecute
     result.changedHeroes should have size 1
-    val ch     = result.changedHeroes.head.asInstanceOf[ChangedHeroC]
+    val ch     = checkedAs[ChangedHeroC](result.changedHeroes.head)
     loyaltyDelta(ch) should be < 0.0
   }
 
@@ -316,9 +316,9 @@ class NewYearActionTest extends AnyFlatSpec with Matchers with BeforeAndAfterEac
     val lowAmbitionResult  = NewYearAction(lowAmbitionGameState).immediateExecute
 
     val highAmbitionHeroAfter =
-      highAmbitionResult.changedHeroes.find(_.heroId == highDiscordHero.id).get.asInstanceOf[ChangedHeroC]
+      checkedAs[ChangedHeroC](highAmbitionResult.changedHeroes.find(_.heroId == highDiscordHero.id).get)
     val lowAmbitionHeroAfter  =
-      lowAmbitionResult.changedHeroes.find(_.heroId == lowDiscordHero.id).get.asInstanceOf[ChangedHeroC]
+      checkedAs[ChangedHeroC](lowAmbitionResult.changedHeroes.find(_.heroId == lowDiscordHero.id).get)
 
     loyaltyDelta(highAmbitionHeroAfter) should be < loyaltyDelta(lowAmbitionHeroAfter)
   }
@@ -340,9 +340,9 @@ class NewYearActionTest extends AnyFlatSpec with Matchers with BeforeAndAfterEac
     val lowAmbitionResult  = NewYearAction(lowAmbitionGameState).immediateExecute
 
     val highAmbitionHeroAfter =
-      highAmbitionResult.changedHeroes.find(_.heroId == highDiscordHero.id).get.asInstanceOf[ChangedHeroC]
+      checkedAs[ChangedHeroC](highAmbitionResult.changedHeroes.find(_.heroId == highDiscordHero.id).get)
     val lowAmbitionHeroAfter  =
-      lowAmbitionResult.changedHeroes.find(_.heroId == highDiscordHero.id).get.asInstanceOf[ChangedHeroC]
+      checkedAs[ChangedHeroC](lowAmbitionResult.changedHeroes.find(_.heroId == highDiscordHero.id).get)
 
     loyaltyDelta(highAmbitionHeroAfter) shouldBe loyaltyDelta(lowAmbitionHeroAfter)
   }
@@ -361,9 +361,9 @@ class NewYearActionTest extends AnyFlatSpec with Matchers with BeforeAndAfterEac
     val result = NewYearAction(modGameState).immediateExecute
 
     val highDiscordHeroAfter =
-      result.changedHeroes.find(_.heroId == highDiscordHero.id).get.asInstanceOf[ChangedHeroC]
+      checkedAs[ChangedHeroC](result.changedHeroes.find(_.heroId == highDiscordHero.id).get)
     val lowDiscordHeroAfter  =
-      result.changedHeroes.find(_.heroId == lowDiscordHero.id).get.asInstanceOf[ChangedHeroC]
+      checkedAs[ChangedHeroC](result.changedHeroes.find(_.heroId == lowDiscordHero.id).get)
 
     loyaltyDelta(highDiscordHeroAfter) should be < loyaltyDelta(lowDiscordHeroAfter)
   }
@@ -387,7 +387,7 @@ class NewYearActionTest extends AnyFlatSpec with Matchers with BeforeAndAfterEac
     val result = NewYearAction(modGameState).immediateExecute
 
     val noDiscordHeroAfter =
-      result.changedHeroes.find(_.heroId == noDiscordHero.id).get.asInstanceOf[ChangedHeroC]
+      checkedAs[ChangedHeroC](result.changedHeroes.find(_.heroId == noDiscordHero.id).get)
 
     loyaltyDelta(noDiscordHeroAfter) shouldBe 1
   }
@@ -409,7 +409,7 @@ class NewYearActionTest extends AnyFlatSpec with Matchers with BeforeAndAfterEac
     val result = NewYearAction(modGameState).immediateExecute
 
     val highDiscordHeroAfter =
-      result.changedHeroes.find(_.heroId == highDiscordHero.id).get.asInstanceOf[ChangedHeroC]
+      checkedAs[ChangedHeroC](result.changedHeroes.find(_.heroId == highDiscordHero.id).get)
 
     loyaltyDelta(highDiscordHeroAfter) shouldBe -3
   }

src/test/scala/net/eagle0/eagle/library/actions/impl/action/PerformFoodConsumptionPhaseActionTest.scala

@@ -1,5 +1,6 @@
 package net.eagle0.eagle.library.actions.impl.action
 
+import net.eagle0.eagle.checkedAs
 import net.eagle0.eagle.library.settings.{MaxBattalionReductionForFoodShortage, MinSupportForTaxes}
 import net.eagle0.eagle.library.EagleInternalException
 import net.eagle0.eagle.model.action_result.{ActionResultT, NotificationDetails}
@@ -108,7 +109,7 @@ class PerformFoodConsumptionPhaseActionTest extends AnyFlatSpec with Matchers wi
 
     val result: ActionResultT = PerformFoodConsumptionPhaseAction(gameState).immediateExecute
 
-    val cp: ChangedProvinceC = result.changedProvinces.head.asInstanceOf[ChangedProvinceC]
+    val cp: ChangedProvinceC = checkedAs[ChangedProvinceC](result.changedProvinces.head)
     cp.foodDelta shouldBe Some(-258)
     result.changedBattalions shouldBe empty
   }
@@ -128,10 +129,10 @@ class PerformFoodConsumptionPhaseActionTest extends AnyFlatSpec with Matchers wi
 
     val result: ActionResultT = PerformFoodConsumptionPhaseAction(gameState).immediateExecute
 
-    val cp: ChangedProvinceC                         = result.changedProvinces.head.asInstanceOf[ChangedProvinceC]
+    val cp: ChangedProvinceC                         = checkedAs[ChangedProvinceC](result.changedProvinces.head)
     cp.foodDelta should contain(-196)
     val changedBattalions: Vector[ChangedBattalionC] =
-      result.changedBattalions.map(cb => cb.asInstanceOf[ChangedBattalionC])
+      result.changedBattalions.map(cb => checkedAs[ChangedBattalionC](cb))
     val battalionSizes: Set[Int]                     = changedBattalions.map(cb => cb.to.size).toSet
     battalionSizes shouldBe Set(189, 457)
   }
@@ -151,10 +152,10 @@ class PerformFoodConsumptionPhaseActionTest extends AnyFlatSpec with Matchers wi
 
     val result: ActionResultT = PerformFoodConsumptionPhaseAction(gameState).immediateExecute
 
-    val cp: ChangedProvinceC                         = result.changedProvinces.head.asInstanceOf[ChangedProvinceC]
+    val cp: ChangedProvinceC                         = checkedAs[ChangedProvinceC](result.changedProvinces.head)
     cp.foodDelta should contain(-196)
     val changedBattalions: Vector[ChangedBattalionC] =
-      result.changedBattalions.map(cb => cb.asInstanceOf[ChangedBattalionC])
+      result.changedBattalions.map(cb => checkedAs[ChangedBattalionC](cb))
     val battalionSizes: Set[Int]                     = changedBattalions.map(cb => cb.to.size).toSet
     battalionSizes shouldBe Set(200, 481)
   }
@@ -205,7 +206,7 @@ class PerformFoodConsumptionPhaseActionTest extends AnyFlatSpec with Matchers wi
 
     val result: ActionResultT = PerformFoodConsumptionPhaseAction(gameState).immediateExecute
 
-    val cp: ChangedProvinceC = result.changedProvinces.head.asInstanceOf[ChangedProvinceC]
+    val cp: ChangedProvinceC = checkedAs[ChangedProvinceC](result.changedProvinces.head)
     cp.removedIncomingArmyIds shouldBe Vector(17)
 
     // Verify the full incoming army structure is preserved (not just supplies)

src/test/scala/net/eagle0/eagle/library/actions/impl/action/PerformForcedTurnBackActionTest.scala

@@ -1,5 +1,6 @@
 package net.eagle0.eagle.library.actions.impl.action
 
+import net.eagle0.eagle.checkedAs
 import net.eagle0.eagle.library.settings.WinterSuppliesLoss
 import net.eagle0.eagle.model.action_result.changed_province.concrete.ChangedProvinceC
 import net.eagle0.eagle.model.action_result.types.ActionResultType.{
@@ -125,7 +126,7 @@ class PerformForcedTurnBackActionTest extends AnyFlatSpec with Matchers with Bef
     first.affectedFactionIds shouldBe Vector(54)
 
     first.changedProvinces should have size 2
-    first.changedProvinces.map(_.asInstanceOf[ChangedProvinceC]) should contain theSameElementsAs Vector(
+    first.changedProvinces.map(checkedAs[ChangedProvinceC](_)) should contain theSameElementsAs Vector(
       ChangedProvinceC(
         provinceId = destinationPid,
         removedIncomingArmyIds = Vector(99)
@@ -188,7 +189,7 @@ class PerformForcedTurnBackActionTest extends AnyFlatSpec with Matchers with Bef
     first.destroyedBattalionIds shouldBe Vector(22)
 
     first.changedProvinces should have size 1
-    val changedProvince = first.changedProvinces.head.asInstanceOf[ChangedProvinceC]
+    val changedProvince = checkedAs[ChangedProvinceC](first.changedProvinces.head)
     changedProvince.provinceId shouldBe destinationPid
     changedProvince.removedIncomingArmyIds shouldBe Vector(99)
     changedProvince.removedHostileArmyFactionIds shouldBe Vector(54)
@@ -264,7 +265,7 @@ class PerformForcedTurnBackActionTest extends AnyFlatSpec with Matchers with Bef
     first.actingFactionId should contain(54)
     first.provinceId should contain(destinationPid)
 
-    first.changedProvinces.map(_.asInstanceOf[ChangedProvinceC]) should contain theSameElementsAs Vector(
+    first.changedProvinces.map(checkedAs[ChangedProvinceC](_)) should contain theSameElementsAs Vector(
       ChangedProvinceC(
         provinceId = destinationPid,
         removedIncomingShipmentIds = Vector(12)
@@ -315,7 +316,7 @@ class PerformForcedTurnBackActionTest extends AnyFlatSpec with Matchers with Bef
     first.actingFactionId should contain(54)
     first.provinceId should contain(destinationPid)
 
-    first.changedProvinces.map(_.asInstanceOf[ChangedProvinceC]) should contain theSameElementsAs Vector(
+    first.changedProvinces.map(checkedAs[ChangedProvinceC](_)) should contain theSameElementsAs Vector(
       ChangedProvinceC(
         provinceId = destinationPid,
         removedIncomingShipmentIds = Vector(12)

src/test/scala/net/eagle0/eagle/library/actions/impl/action/PerformProvinceEventsActionTest.scala

@@ -1,6 +1,7 @@
 package net.eagle0.eagle.library.actions.impl.action
 
 import net.eagle0.common.SeededRandom
+import net.eagle0.eagle.checkedAs
 import net.eagle0.eagle.library.settings.{
   BaseBeastsCount,
   BeastsDurationMonths,
@@ -271,7 +272,7 @@ class PerformProvinceEventsActionTest extends AnyFlatSpec with BeforeAndAfterEac
 
     val newEvents   = cp.newProvinceEvents.get
     newEvents.should(have).size(1)
-    val beastsEvent = newEvents.head.asInstanceOf[BeastsEventT]
+    val beastsEvent = checkedAs[BeastsEventT](newEvents.head)
     beastsEvent.count.shouldBe(100)
     beastsEvent.startDate.shouldBe(tDate(1501, 8))
     beastsEvent.endDate.shouldBe(tDate(1501, 12))
@@ -534,9 +535,10 @@ class PerformProvinceEventsActionTest extends AnyFlatSpec with BeforeAndAfterEac
   it should "not add an imminent riot if there is a festival" in {
     val gsWithFestival = imminentRiotGS.copy(
       provinces = Map(
-        7 -> imminentRiotGS
-          .provinces(7)
-          .asInstanceOf[ProvinceC]
+        7 -> checkedAs[ProvinceC](
+          imminentRiotGS
+            .provinces(7)
+        )
           .copy(
             activeEvents = Vector(
               FestivalEventT(
@@ -560,9 +562,10 @@ class PerformProvinceEventsActionTest extends AnyFlatSpec with BeforeAndAfterEac
   it should "not add an imminent riot if it hasn't been long enough based on support" in {
     val gsWithLastRiot = imminentRiotGS.copy(
       provinces = Map(
-        7 -> imminentRiotGS
-          .provinces(7)
-          .asInstanceOf[ProvinceC]
+        7 -> checkedAs[ProvinceC](
+          imminentRiotGS
+            .provinces(7)
+        )
           .copy(
             lastRiotDate = Some(tDate(1501, 3))
           )
@@ -582,9 +585,10 @@ class PerformProvinceEventsActionTest extends AnyFlatSpec with BeforeAndAfterEac
   it should "add a riot if it *has* been long enough based on support" in {
     val gsWithOldRiot = imminentRiotGS.copy(
       provinces = Map(
-        7 -> imminentRiotGS
-          .provinces(7)
-          .asInstanceOf[ProvinceC]
+        7 -> checkedAs[ProvinceC](
+          imminentRiotGS
+            .provinces(7)
+        )
           .copy(
             lastRiotDate = Some(tDate(1500, 3))
           )
@@ -692,9 +696,10 @@ class PerformProvinceEventsActionTest extends AnyFlatSpec with BeforeAndAfterEac
   it should "not add an imminent riot if the province is under attack" in {
     val gsWithIncoming = imminentRiotGS.copy(
       provinces = Map(
-        7 -> imminentRiotGS
-          .provinces(7)
-          .asInstanceOf[ProvinceC]
+        7 -> checkedAs[ProvinceC](
+          imminentRiotGS
+            .provinces(7)
+        )
           .copy(
             incomingArmies = Vector(
               MovingArmy(
@@ -724,9 +729,10 @@ class PerformProvinceEventsActionTest extends AnyFlatSpec with BeforeAndAfterEac
   it should "still add an imminent riot if the province has a friendly incoming" in {
     val gsWithFriendlyIncoming = imminentRiotGS.copy(
       provinces = Map(
-        7 -> imminentRiotGS
-          .provinces(7)
-          .asInstanceOf[ProvinceC]
+        7 -> checkedAs[ProvinceC](
+          imminentRiotGS
+            .provinces(7)
+        )
           .copy(
             incomingArmies = Vector(
               MovingArmy(
@@ -757,9 +763,10 @@ class PerformProvinceEventsActionTest extends AnyFlatSpec with BeforeAndAfterEac
   it should "not add an imminent riot if the support is under tax level" in {
     val gsWithLowSupport = imminentRiotGS.copy(
       provinces = Map(
-        7 -> imminentRiotGS
-          .provinces(7)
-          .asInstanceOf[ProvinceC]
+        7 -> checkedAs[ProvinceC](
+          imminentRiotGS
+            .provinces(7)
+        )
           .copy(
             support = 38
           )
@@ -778,9 +785,10 @@ class PerformProvinceEventsActionTest extends AnyFlatSpec with BeforeAndAfterEac
   it should "still add an imminent riot if the support is over 55" in {
     val gsWithHighSupport = imminentRiotGS.copy(
       provinces = Map(
-        7 -> imminentRiotGS
-          .provinces(7)
-          .asInstanceOf[ProvinceC]
+        7 -> checkedAs[ProvinceC](
+          imminentRiotGS
+            .provinces(7)
+        )
           .copy(
             support = 55
           )
@@ -821,7 +829,7 @@ class PerformProvinceEventsActionTest extends AnyFlatSpec with BeforeAndAfterEac
     cp.get.provinceId.shouldBe(7)
     val newEvents     = cp.get.newProvinceEvents.get
     newEvents.should(have).size(1)
-    val blizzardEvent = newEvents.head.asInstanceOf[BlizzardEventT]
+    val blizzardEvent = checkedAs[BlizzardEventT](newEvents.head)
     blizzardEvent.startDate.shouldBe(tDate(1501, 12))
     blizzardEvent.endDate.shouldBe(tDate(1502, 3))
   }
@@ -840,7 +848,7 @@ class PerformProvinceEventsActionTest extends AnyFlatSpec with BeforeAndAfterEac
     cp.get.provinceId.shouldBe(7)
     val newEvents     = cp.get.newProvinceEvents.get
     newEvents.should(have).size(1)
-    val blizzardEvent = newEvents.head.asInstanceOf[BlizzardEventT]
+    val blizzardEvent = checkedAs[BlizzardEventT](newEvents.head)
     blizzardEvent.startDate.shouldBe(tDate(1502, 2))
     blizzardEvent.endDate.shouldBe(tDate(1502, 3))
   }
@@ -871,9 +879,10 @@ class PerformProvinceEventsActionTest extends AnyFlatSpec with BeforeAndAfterEac
   it should "not add a blizzard if there is already a blizzard" in {
     val alreadyBlizzardGS = blizzardGS.copy(
       provinces = Map(
-        7 -> blizzardGS
-          .provinces(7)
-          .asInstanceOf[ProvinceC]
+        7 -> checkedAs[ProvinceC](
+          blizzardGS
+            .provinces(7)
+        )
           .copy(
             activeEvents = Vector(
               BlizzardEventT(
@@ -919,7 +928,7 @@ class PerformProvinceEventsActionTest extends AnyFlatSpec with BeforeAndAfterEac
     cp.get.provinceId.shouldBe(7)
     val newEvents  = cp.get.newProvinceEvents.get
     newEvents.should(have).size(1)
-    val floodEvent = newEvents.head.asInstanceOf[FloodEventT]
+    val floodEvent = checkedAs[FloodEventT](newEvents.head)
     floodEvent.startDate.shouldBe(tDate(1501, 7))
     floodEvent.endDate.shouldBe(tDate(1501, 9))
   }
@@ -927,9 +936,10 @@ class PerformProvinceEventsActionTest extends AnyFlatSpec with BeforeAndAfterEac
   it should "not add a flood if there's a drought" in {
     val alreadyDroughtGS = floodGS.copy(
       provinces = Map(
-        7 -> floodGS
-          .provinces(7)
-          .asInstanceOf[ProvinceC]
+        7 -> checkedAs[ProvinceC](
+          floodGS
+            .provinces(7)
+        )
           .copy(
             activeEvents = Vector(
               DroughtEventT(
@@ -975,7 +985,7 @@ class PerformProvinceEventsActionTest extends AnyFlatSpec with BeforeAndAfterEac
     cp.get.provinceId.shouldBe(7)
     val newEvents     = cp.get.newProvinceEvents.get
     newEvents.should(have).size(1)
-    val festivalEvent = newEvents.head.asInstanceOf[FestivalEventT]
+    val festivalEvent = checkedAs[FestivalEventT](newEvents.head)
     festivalEvent.startDate.shouldBe(tDate(1501, 3))
     festivalEvent.endDate.shouldBe(tDate(1501, 6))
   }
@@ -993,7 +1003,7 @@ class PerformProvinceEventsActionTest extends AnyFlatSpec with BeforeAndAfterEac
     cp.get.provinceId.shouldBe(7)
     val newEvents     = cp.get.newProvinceEvents.get
     newEvents.should(have).size(1)
-    val festivalEvent = newEvents.head.asInstanceOf[FestivalEventT]
+    val festivalEvent = checkedAs[FestivalEventT](newEvents.head)
     festivalEvent.startDate.shouldBe(tDate(1501, 9))
     festivalEvent.endDate.shouldBe(tDate(1501, 12))
   }
@@ -1024,9 +1034,10 @@ class PerformProvinceEventsActionTest extends AnyFlatSpec with BeforeAndAfterEac
   it should "not add a festival if there is already a festival" in {
     val gsWithFestival = festivalGS.copy(
       provinces = Map(
-        7 -> festivalGS
-          .provinces(7)
-          .asInstanceOf[ProvinceC]
+        7 -> checkedAs[ProvinceC](
+          festivalGS
+            .provinces(7)
+        )
           .copy(
             activeEvents = Vector(
               FestivalEventT(
@@ -1050,9 +1061,10 @@ class PerformProvinceEventsActionTest extends AnyFlatSpec with BeforeAndAfterEac
   it should "not add a festival if there is a drought" in {
     val gsWithDrought = festivalGS.copy(
       provinces = Map(
-        7 -> festivalGS
-          .provinces(7)
-          .asInstanceOf[ProvinceC]
+        7 -> checkedAs[ProvinceC](
+          festivalGS
+            .provinces(7)
+        )
           .copy(
             activeEvents = Vector(
               DroughtEventT(
@@ -1130,11 +1142,11 @@ class PerformProvinceEventsActionTest extends AnyFlatSpec with BeforeAndAfterEac
       )
     )
 
-    val results = PerformProvinceEventsAction(tGameState).results(SeededRandom(1L)).asInstanceOf[Vector[ActionResultC]]
+    val results = PerformProvinceEventsAction(tGameState).results(SeededRandom(1L)).map(checkedAs[ActionResultC](_))
     val changedFactions = results.head.changedFactions
     changedFactions.should(have).size(1)
 
-    val cf = changedFactions.head.asInstanceOf[ChangedFactionC]
+    val cf = checkedAs[ChangedFactionC](changedFactions.head)
     cf.factionId.shouldBe(4)
     cf.newPrestigeModifiers.should(have).size(1)
     cf.newPrestigeModifiers.head.prestigeModifierType.shouldBe(PrestigeModifier.Type.Festival)
@@ -1291,7 +1303,7 @@ class PerformProvinceEventsActionTest extends AnyFlatSpec with BeforeAndAfterEac
 
     val newEvents     = cp.newProvinceEvents.get
     newEvents.should(have).size(1)
-    val epidemicEvent = newEvents.head.asInstanceOf[EpidemicEventT]
+    val epidemicEvent = checkedAs[EpidemicEventT](newEvents.head)
     epidemicEvent.startDate.shouldBe(tDate(1501, 7))
   }
 
@@ -1440,7 +1452,7 @@ class PerformProvinceEventsActionTest extends AnyFlatSpec with BeforeAndAfterEac
 
     val newEvents     = cp.newProvinceEvents.get
     newEvents.should(have).size(1)
-    val epidemicEvent = newEvents.head.asInstanceOf[EpidemicEventT]
+    val epidemicEvent = checkedAs[EpidemicEventT](newEvents.head)
     epidemicEvent.startDate.shouldBe(tDate(1501, 7))
   }
 
@@ -1492,11 +1504,11 @@ class PerformProvinceEventsActionTest extends AnyFlatSpec with BeforeAndAfterEac
       )
     )
 
-    val results = PerformProvinceEventsAction(tGameState).results(SeededRandom(1L)).asInstanceOf[Vector[ActionResultC]]
+    val results = PerformProvinceEventsAction(tGameState).results(SeededRandom(1L)).map(checkedAs[ActionResultC](_))
     val changedBattalions = results.head.changedBattalions
     changedBattalions.should(have).size(2)
     changedBattalions
-      .map(_.asInstanceOf[ChangedBattalionC])
+      .map(checkedAs[ChangedBattalionC](_))
       .map(cb => (cb.to.id, cb.to.size))
       .toSet
       .shouldBe(Set((19, 212), (25, 850)))
@@ -1535,11 +1547,11 @@ class PerformProvinceEventsActionTest extends AnyFlatSpec with BeforeAndAfterEac
       )
     )
 
-    val results = PerformProvinceEventsAction(tGameState).results(SeededRandom(1L)).asInstanceOf[Vector[ActionResultC]]
+    val results = PerformProvinceEventsAction(tGameState).results(SeededRandom(1L)).map(checkedAs[ActionResultC](_))
     val changedHeroes = results.head.changedHeroes
     changedHeroes.should(have).size(3)
     changedHeroes
-      .map(_.asInstanceOf[ChangedHeroC])
+      .map(checkedAs[ChangedHeroC](_))
       .map(ch => (ch.heroId, ch.vigorChange))
       .toSet
       .shouldBe(
@@ -1575,7 +1587,7 @@ class PerformProvinceEventsActionTest extends AnyFlatSpec with BeforeAndAfterEac
     cp.get.provinceId.shouldBe(7)
     val newEvents    = cp.get.newProvinceEvents.get
     newEvents.should(have).size(1)
-    val droughtEvent = newEvents.head.asInstanceOf[DroughtEventT]
+    val droughtEvent = checkedAs[DroughtEventT](newEvents.head)
     droughtEvent.startDate.shouldBe(tDate(1501, 7))
     droughtEvent.endDate.shouldBe(tDate(1501, 10))
   }
@@ -1606,9 +1618,10 @@ class PerformProvinceEventsActionTest extends AnyFlatSpec with BeforeAndAfterEac
   it should "not add a drought if there is already a drought" in {
     val alreadyDroughtGS = droughtGS.copy(
       provinces = Map(
-        7 -> droughtGS
-          .provinces(7)
-          .asInstanceOf[ProvinceC]
+        7 -> checkedAs[ProvinceC](
+          droughtGS
+            .provinces(7)
+        )
           .copy(
             activeEvents = Vector(
               DroughtEventT(
@@ -1632,9 +1645,10 @@ class PerformProvinceEventsActionTest extends AnyFlatSpec with BeforeAndAfterEac
   it should "not add a drought if there is a flood" in {
     val alreadyFloodGS = droughtGS.copy(
       provinces = Map(
-        7 -> droughtGS
-          .provinces(7)
-          .asInstanceOf[ProvinceC]
+        7 -> checkedAs[ProvinceC](
+          droughtGS
+            .provinces(7)
+        )
           .copy(
             activeEvents = Vector(
               FloodEventT(
@@ -1659,7 +1673,7 @@ class PerformProvinceEventsActionTest extends AnyFlatSpec with BeforeAndAfterEac
     val earlyGS    = droughtGS.copy(currentRoundId = 5)
     val tGameState = earlyGS
     val results    =
-      PerformProvinceEventsAction(tGameState).results(SeededRandom(1L)).asInstanceOf[Vector[ActionResultC]].head
+      PerformProvinceEventsAction(tGameState).results(SeededRandom(1L)).map(checkedAs[ActionResultC](_)).head
 
     results.actionResultType.shouldBe(ProvinceEventsChanged)
     results.newRoundPhase.shouldBe(Some(RoundPhase.ForcedTurnBack))

src/test/scala/net/eagle0/eagle/library/actions/impl/action/PerformProvinceMoveResolutionActionTest.scala

@@ -1,6 +1,7 @@
 package net.eagle0.eagle.library.actions.impl.action
 
 import net.eagle0.common.SeededRandom
+import net.eagle0.eagle.checkedAs
 import net.eagle0.eagle.library.actions.applier.ActionResultApplierImpl
 import net.eagle0.eagle.library.EagleInternalException
 import net.eagle0.eagle.model.action_result.changed_province.concrete.ChangedProvinceC
@@ -138,11 +139,11 @@ class PerformProvinceMoveResolutionActionTest extends AnyFlatSpec with Matchers
   "a single province with a single incoming army" should "produce the friendly move event for that army" in {
     val results = getResults(startingState)
 
-    val firstResult = results.head.asInstanceOf[ActionResultC]
+    val firstResult = checkedAs[ActionResultC](results.head)
     firstResult.actionResultType shouldBe FriendlyMove
     firstResult.provinceId should contain(province1.id)
 
-    val changedProvince = firstResult.changedProvinces.head.asInstanceOf[ChangedProvinceC]
+    val changedProvince = checkedAs[ChangedProvinceC](firstResult.changedProvinces.head)
     changedProvince.newRulingFactionHeroIds shouldBe Vector(1)
     changedProvince.newBattalionIds shouldBe Vector(1)
   }
@@ -161,12 +162,10 @@ class PerformProvinceMoveResolutionActionTest extends AnyFlatSpec with Matchers
     val moveResults = results.filter(_.actionResultType == FriendlyMove)
     moveResults.should(have.size(2))
 
-    forAll(moveResults) { r =>
-      r.asInstanceOf[ActionResultC].provinceId should contain(p.id)
-    }
+    forAll(moveResults)(r => checkedAs[ActionResultC](r).provinceId should contain(p.id))
 
-    val lastResult          = moveResults.last.asInstanceOf[ActionResultC]
-    val lastChangedProvince = lastResult.changedProvinces.head.asInstanceOf[ChangedProvinceC]
+    val lastResult          = checkedAs[ActionResultC](moveResults.last)
+    val lastChangedProvince = checkedAs[ChangedProvinceC](lastResult.changedProvinces.head)
     lastChangedProvince.newRulingFactionHeroIds should contain theSameElementsAs Vector(4)
     lastChangedProvince.newBattalionIds should contain theSameElementsAs Vector(4)
   }
@@ -203,7 +202,7 @@ class PerformProvinceMoveResolutionActionTest extends AnyFlatSpec with Matchers
         destinationProvinceId = 300,
         army = movingArmy.army.copy(fleeProvinceId = None)
       )
-      val hostileProvince    = startingState.provinces(300).asInstanceOf[ProvinceC]
+      val hostileProvince    = checkedAs[ProvinceC](startingState.provinces(300))
       val hostileWithArrival = hostileProvince.copy(
         incomingArmies = Vector(fleeingArmy)
       )
@@ -248,15 +247,15 @@ class PerformProvinceMoveResolutionActionTest extends AnyFlatSpec with Matchers
     forAll(moveResults)(_.actionResultType shouldBe FriendlyMove)
 
     forExactly(1, moveResults) { result =>
-      val ar = result.asInstanceOf[ActionResultC]
+      val ar = checkedAs[ActionResultC](result)
       ar.provinceId should contain(province1.id)
-      ar.changedProvinces.map(_.asInstanceOf[ChangedProvinceC].provinceId) shouldBe Vector(province1.id)
+      ar.changedProvinces.map(checkedAs[ChangedProvinceC](_).provinceId) shouldBe Vector(province1.id)
     }
 
     forExactly(1, moveResults) { result =>
-      val ar = result.asInstanceOf[ActionResultC]
+      val ar = checkedAs[ActionResultC](result)
       ar.provinceId should contain(province2.id)
-      ar.changedProvinces.map(_.asInstanceOf[ChangedProvinceC].provinceId) shouldBe Vector(province2.id)
+      ar.changedProvinces.map(checkedAs[ChangedProvinceC](_).provinceId) shouldBe Vector(province2.id)
     }
   }
 

src/test/scala/net/eagle0/eagle/library/actions/impl/action/PerformReconResolutionActionTest.scala

@@ -3,6 +3,7 @@ package net.eagle0.eagle.library.actions.impl.action
 import scala.util.Random
 
 import net.eagle0.common.SeededRandom
+import net.eagle0.eagle.checkedAs
 import net.eagle0.eagle.library.actions.applier.ActionResultApplierImpl
 import net.eagle0.eagle.library.settings.{BaseResourceLimit, PerDevelopmentResourceLimit}
 import net.eagle0.eagle.model.action_result.changed_province.concrete.ChangedProvinceC
@@ -130,38 +131,38 @@ class PerformReconResolutionActionTest extends AnyFlatSpec with BeforeAndAfterEa
   }
 
   "perform one" should "remove the incoming recon" in {
-    val oneResult = PerformReconResolutionAction(gameState, actionResultApplier)
-      .oneResult(
-        provinceId = 3,
-        incomingEndTurnAction = incomingRecon,
-        functionalRandom = functionalRandom
-      )
-      .newValue
-      .asInstanceOf[ActionResultC]
+    val oneResult = checkedAs[ActionResultC](
+      PerformReconResolutionAction(gameState, actionResultApplier)
+        .oneResult(
+          provinceId = 3,
+          incomingEndTurnAction = incomingRecon,
+          functionalRandom = functionalRandom
+        )
+        .newValue
+    )
 
     oneResult.actionResultType shouldBe ReconSucceeded
-    val targetProvinceCP = oneResult.changedProvinces
-      .find(_.asInstanceOf[ChangedProvinceC].provinceId == 3)
-      .get
-      .asInstanceOf[ChangedProvinceC]
+    val targetProvinceCP = oneResult.changedProvinces.collectFirst {
+      case cp: ChangedProvinceC if cp.provinceId == 3 => cp
+    }.get
     targetProvinceCP.removedIncomingEndTurnActions shouldBe Vector(incomingRecon)
   }
 
   it should "return the hero to the origin province if it's still owned" in {
-    val oneResult = PerformReconResolutionAction(gameState, actionResultApplier)
-      .oneResult(
-        provinceId = 3,
-        incomingEndTurnAction = incomingRecon,
-        functionalRandom = functionalRandom
-      )
-      .newValue
-      .asInstanceOf[ActionResultC]
+    val oneResult = checkedAs[ActionResultC](
+      PerformReconResolutionAction(gameState, actionResultApplier)
+        .oneResult(
+          provinceId = 3,
+          incomingEndTurnAction = incomingRecon,
+          functionalRandom = functionalRandom
+        )
+        .newValue
+    )
 
     oneResult.actionResultType shouldBe ReconSucceeded
-    val originProvinceCP = oneResult.changedProvinces
-      .find(_.asInstanceOf[ChangedProvinceC].provinceId == 9)
-      .get
-      .asInstanceOf[ChangedProvinceC]
+    val originProvinceCP = oneResult.changedProvinces.collectFirst {
+      case cp: ChangedProvinceC if cp.provinceId == 9 => cp
+    }.get
     originProvinceCP.newRulingFactionHeroIds shouldBe Vector(19)
   }
 
@@ -170,20 +171,20 @@ class PerformReconResolutionActionTest extends AnyFlatSpec with BeforeAndAfterEa
     val gsWithLostProvince        = makeGameState(provincesWithLostProvince, baseHeroes, baseFactions)
 
     val oneResult =
-      PerformReconResolutionAction(gsWithLostProvince, actionResultApplier)
-        .oneResult(
-          provinceId = 3,
-          incomingEndTurnAction = incomingRecon,
-          functionalRandom = functionalRandom
-        )
-        .newValue
-        .asInstanceOf[ActionResultC]
+      checkedAs[ActionResultC](
+        PerformReconResolutionAction(gsWithLostProvince, actionResultApplier)
+          .oneResult(
+            provinceId = 3,
+            incomingEndTurnAction = incomingRecon,
+            functionalRandom = functionalRandom
+          )
+          .newValue
+      )
 
     oneResult.actionResultType shouldBe ReconSucceeded
-    val returnProvinceCP = oneResult.changedProvinces
-      .find(_.asInstanceOf[ChangedProvinceC].provinceId == 10)
-      .get
-      .asInstanceOf[ChangedProvinceC]
+    val returnProvinceCP = oneResult.changedProvinces.collectFirst {
+      case cp: ChangedProvinceC if cp.provinceId == 10 => cp
+    }.get
     returnProvinceCP.newRulingFactionHeroIds shouldBe Vector(19)
   }
 
@@ -194,37 +195,38 @@ class PerformReconResolutionActionTest extends AnyFlatSpec with BeforeAndAfterEa
     val gsWithLostProvinces         = makeGameState(provincesWithLostProvinces, baseHeroes, baseFactions)
 
     val oneResult =
-      PerformReconResolutionAction(gsWithLostProvinces, actionResultApplier)
+      checkedAs[ActionResultC](
+        PerformReconResolutionAction(gsWithLostProvinces, actionResultApplier)
+          .oneResult(
+            provinceId = 3,
+            incomingEndTurnAction = incomingRecon,
+            functionalRandom = functionalRandom
+          )
+          .newValue
+      )
+
+    oneResult.actionResultType shouldBe ReconSucceeded
+    val originProvinceCP = oneResult.changedProvinces.collectFirst {
+      case cp: ChangedProvinceC if cp.provinceId == 9 => cp
+    }.get
+    originProvinceCP.newUnaffiliatedHeroes.map(_.heroId) shouldBe Vector(19)
+  }
+
+  it should "update the faction with the info about the province" in {
+    val oneResult = checkedAs[ActionResultC](
+      PerformReconResolutionAction(gameState, actionResultApplier)
         .oneResult(
           provinceId = 3,
           incomingEndTurnAction = incomingRecon,
           functionalRandom = functionalRandom
         )
         .newValue
-        .asInstanceOf[ActionResultC]
-
-    oneResult.actionResultType shouldBe ReconSucceeded
-    val originProvinceCP = oneResult.changedProvinces
-      .find(_.asInstanceOf[ChangedProvinceC].provinceId == 9)
-      .get
-      .asInstanceOf[ChangedProvinceC]
-    originProvinceCP.newUnaffiliatedHeroes.map(_.heroId) shouldBe Vector(19)
-  }
-
-  it should "update the faction with the info about the province" in {
-    val oneResult = PerformReconResolutionAction(gameState, actionResultApplier)
-      .oneResult(
-        provinceId = 3,
-        incomingEndTurnAction = incomingRecon,
-        functionalRandom = functionalRandom
-      )
-      .newValue
-      .asInstanceOf[ActionResultC]
+    )
 
     oneResult.actionResultType shouldBe ReconSucceeded
     oneResult.changedFactions should have size 1
 
-    val cf = oneResult.changedFactions.head.asInstanceOf[ChangedFactionC]
+    val cf = checkedAs[ChangedFactionC](oneResult.changedFactions.head)
     cf.updatedReconnedProvinces should have size 1
 
     val rp = cf.updatedReconnedProvinces.head
@@ -233,14 +235,15 @@ class PerformReconResolutionActionTest extends AnyFlatSpec with BeforeAndAfterEa
   }
 
   it should "extend client text visibility for the heroes in the reconned province" in {
-    val oneResult = PerformReconResolutionAction(gameState, actionResultApplier)
-      .oneResult(
-        provinceId = 3,
-        incomingEndTurnAction = incomingRecon,
-        functionalRandom = functionalRandom
-      )
-      .newValue
-      .asInstanceOf[ActionResultC]
+    val oneResult = checkedAs[ActionResultC](
+      PerformReconResolutionAction(gameState, actionResultApplier)
+        .oneResult(
+          provinceId = 3,
+          incomingEndTurnAction = incomingRecon,
+          functionalRandom = functionalRandom
+        )
+        .newValue
+    )
 
     oneResult.clientTextVisibilityExtensions should contain theSameElementsAs Vector(
       ClientTextVisibilityExtensionC(

src/test/scala/net/eagle0/eagle/library/actions/impl/action/PrisonerExchangeActionTest.scala

@@ -1,5 +1,6 @@
 package net.eagle0.eagle.library.actions.impl.action
 
+import net.eagle0.eagle.checkedAs
 import net.eagle0.eagle.library.actions.impl.action.PrisonerExchangeAction.{ExchangeMatch, ExchangeableHeroInfo}
 import net.eagle0.eagle.model.action_result.changed_province.concrete.ChangedProvinceC
 import net.eagle0.eagle.model.action_result.concrete.ChangedHeroC
@@ -275,7 +276,7 @@ class PrisonerExchangeActionTest extends AnyFlatSpec with Matchers {
     val headResult = results.head
 
     headResult.actionResultType shouldBe PrisonersExchanged
-    headResult.changedProvinces.map(_.asInstanceOf[ChangedProvinceC]) should contain theSameElementsAs Vector(
+    headResult.changedProvinces.map(checkedAs[ChangedProvinceC](_)) should contain theSameElementsAs Vector(
       ChangedProvinceC(
         provinceId = 5,
         removedUnaffiliatedHeroIds = Vector(31),

src/test/scala/net/eagle0/eagle/library/actions/impl/action/ResolveBattleActionTest.scala

@@ -1,5 +1,6 @@
 package net.eagle0.eagle.library.actions.impl.action
 
+import net.eagle0.eagle.checkedAs
 import net.eagle0.eagle.library.actions.applier.ActionResultApplierImpl
 import net.eagle0.eagle.library.settings.{
   BattleAgricultureDevastationDelta,
@@ -785,11 +786,9 @@ class ResolveBattleActionTest extends AnyFlatSpec with MockFactory with Matchers
     val battleEndedResult = results.find(x => x.actionResultType == BattleEnded)
     battleEndedResult should not be empty
 
-    val defenderProvinceCP = battleEndedResult.get.changedProvinces.find {
-      case cpc: ChangedProvinceC => cpc.provinceId == defenderProvinceId
-      case _                     => false
+    val defenderProvinceCP = battleEndedResult.get.changedProvinces.collectFirst {
+      case cpc: ChangedProvinceC if cpc.provinceId == defenderProvinceId => cpc
     }.get
-      .asInstanceOf[ChangedProvinceC]
 
     // Outlawed defender should be added as an unaffiliated hero (outlaw)
     defenderProvinceCP.newUnaffiliatedHeroes.map(_.heroId) should contain(7)
@@ -854,11 +853,9 @@ class ResolveBattleActionTest extends AnyFlatSpec with MockFactory with Matchers
     battleEndedResult.get.destroyedBattalionIds should contain(10)
 
     // Battalion should also be removed from the province
-    val defenderProvinceCP = battleEndedResult.get.changedProvinces.find {
-      case cpc: ChangedProvinceC => cpc.provinceId == defenderProvinceId
-      case _                     => false
+    val defenderProvinceCP = battleEndedResult.get.changedProvinces.collectFirst {
+      case cpc: ChangedProvinceC if cpc.provinceId == defenderProvinceId => cpc
     }.get
-      .asInstanceOf[ChangedProvinceC]
     defenderProvinceCP.removedBattalionIds should contain(10)
   }
 
@@ -1120,11 +1117,9 @@ class ResolveBattleActionTest extends AnyFlatSpec with MockFactory with Matchers
 
     battleEndedResult should not be empty
 
-    val cp = battleEndedResult.get.changedProvinces.find {
-      case cpc: ChangedProvinceC => cpc.provinceId == defenderProvinceId
-      case _                     => false
+    val cp = battleEndedResult.get.changedProvinces.collectFirst {
+      case cpc: ChangedProvinceC if cpc.provinceId == defenderProvinceId => cpc
     }.get
-      .asInstanceOf[ChangedProvinceC]
     cp.newCapturedHeroes should contain(
       CapturedHero(
         heroId = 7,
@@ -1178,11 +1173,9 @@ class ResolveBattleActionTest extends AnyFlatSpec with MockFactory with Matchers
 
     battleEndedResult should not be empty
 
-    val cp = battleEndedResult.get.changedProvinces.find {
-      case cpc: ChangedProvinceC => cpc.provinceId == defenderProvinceId
-      case _                     => false
+    val cp = battleEndedResult.get.changedProvinces.collectFirst {
+      case cpc: ChangedProvinceC if cpc.provinceId == defenderProvinceId => cpc
     }.get
-      .asInstanceOf[ChangedProvinceC]
     cp.newCapturedHeroes should contain(
       CapturedHero(
         heroId = 7,
@@ -1227,11 +1220,9 @@ class ResolveBattleActionTest extends AnyFlatSpec with MockFactory with Matchers
 
     battleEndedResult should not be empty
 
-    val changedDefenderProvince = battleEndedResult.get.changedProvinces.find {
-      case cpc: ChangedProvinceC => cpc.provinceId == defenderProvinceId
-      case _                     => false
+    val changedDefenderProvince = battleEndedResult.get.changedProvinces.collectFirst {
+      case cpc: ChangedProvinceC if cpc.provinceId == defenderProvinceId => cpc
     }.get
-      .asInstanceOf[ChangedProvinceC]
 
     changedDefenderProvince.goldDelta should contain(500)
     changedDefenderProvince.foodDelta should contain(700)
@@ -1254,11 +1245,9 @@ class ResolveBattleActionTest extends AnyFlatSpec with MockFactory with Matchers
 
     battleEndedResult should not be empty
 
-    val changedDefenderProvince = battleEndedResult.get.changedProvinces.find {
-      case cpc: ChangedProvinceC => cpc.provinceId == defenderProvinceId
-      case _                     => false
+    val changedDefenderProvince = battleEndedResult.get.changedProvinces.collectFirst {
+      case cpc: ChangedProvinceC if cpc.provinceId == defenderProvinceId => cpc
     }.get
-      .asInstanceOf[ChangedProvinceC]
 
     changedDefenderProvince.economyDevastationDelta should contain(15)
     changedDefenderProvince.agricultureDevastationDelta should contain(12)
@@ -1282,11 +1271,9 @@ class ResolveBattleActionTest extends AnyFlatSpec with MockFactory with Matchers
 
     battleEndedResult should not be empty
 
-    val changedDefenderProvince = battleEndedResult.get.changedProvinces.find {
-      case cpc: ChangedProvinceC => cpc.provinceId == defenderProvinceId
-      case _                     => false
+    val changedDefenderProvince = battleEndedResult.get.changedProvinces.collectFirst {
+      case cpc: ChangedProvinceC if cpc.provinceId == defenderProvinceId => cpc
     }.get
-      .asInstanceOf[ChangedProvinceC]
     changedDefenderProvince.newBattleRevelations should have size 1
     changedDefenderProvince.newBattleRevelations.head shouldBe BattleRevelation(
       provinceId = defenderProvinceId,
@@ -1338,11 +1325,9 @@ class ResolveBattleActionTest extends AnyFlatSpec with MockFactory with Matchers
 
     battleEndedResult should not be empty
 
-    val fleeProvinceCP = battleEndedResult.get.changedProvinces.find {
-      case cpc: ChangedProvinceC => cpc.provinceId == 39
-      case _                     => false
+    val fleeProvinceCP = battleEndedResult.get.changedProvinces.collectFirst {
+      case cpc: ChangedProvinceC if cpc.provinceId == 39 => cpc
     }.get
-      .asInstanceOf[ChangedProvinceC]
 
     fleeProvinceCP.provinceId shouldBe 39
     fleeProvinceCP.newIncomingArmies should have size 1
@@ -1399,11 +1384,9 @@ class ResolveBattleActionTest extends AnyFlatSpec with MockFactory with Matchers
 
     battleEndedResult should not be empty
 
-    val attackerFleeProvinceCP = battleEndedResult.get.changedProvinces.find {
-      case cpc: ChangedProvinceC => cpc.provinceId == attackerProvinceId
-      case _                     => false
+    val attackerFleeProvinceCP = battleEndedResult.get.changedProvinces.collectFirst {
+      case cpc: ChangedProvinceC if cpc.provinceId == attackerProvinceId => cpc
     }.get
-      .asInstanceOf[ChangedProvinceC]
 
     attackerFleeProvinceCP.provinceId shouldBe attackerProvinceId
     attackerFleeProvinceCP.newIncomingArmies should have size 1
@@ -1548,11 +1531,9 @@ class ResolveBattleActionTest extends AnyFlatSpec with MockFactory with Matchers
 
     battleEndedResult should not be empty
 
-    val cp = battleEndedResult.get.changedProvinces.find {
-      case cpc: ChangedProvinceC => cpc.provinceId == defenderProvinceId
-      case _                     => false
+    val cp = battleEndedResult.get.changedProvinces.collectFirst {
+      case cpc: ChangedProvinceC if cpc.provinceId == defenderProvinceId => cpc
     }.get
-      .asInstanceOf[ChangedProvinceC]
     cp.newCapturedHeroes should contain(
       CapturedHero(
         heroId = 1,
@@ -1606,11 +1587,9 @@ class ResolveBattleActionTest extends AnyFlatSpec with MockFactory with Matchers
 
     battleEndedResult should not be empty
 
-    val cp = battleEndedResult.get.changedProvinces.find {
-      case cpc: ChangedProvinceC => cpc.provinceId == defenderProvinceId
-      case _                     => false
+    val cp = battleEndedResult.get.changedProvinces.collectFirst {
+      case cpc: ChangedProvinceC if cpc.provinceId == defenderProvinceId => cpc
     }.get
-      .asInstanceOf[ChangedProvinceC]
     cp.newCapturedHeroes should contain(
       CapturedHero(
         heroId = 8,
@@ -1709,7 +1688,7 @@ class ResolveBattleActionTest extends AnyFlatSpec with MockFactory with Matchers
 
     val battleEndedResult = results.find(x => x.actionResultType == BattleEnded).get
     battleEndedResult.changedProvinces.exists { cp =>
-      val cpc = cp.asInstanceOf[ChangedProvinceC]
+      val cpc = checkedAs[ChangedProvinceC](cp)
       cpc.provinceId == defenderFleeProvince.id && cpc.changedUnaffiliatedHeroes.nonEmpty
     } shouldBe false
   }
@@ -1755,9 +1734,7 @@ class ResolveBattleActionTest extends AnyFlatSpec with MockFactory with Matchers
 
     forAll(results) { result =>
       result.actionResultType should not be QuestFulfilled
-      forAll(result.changedProvinces) { cp =>
-        cp.asInstanceOf[ChangedProvinceC].changedUnaffiliatedHeroes shouldBe empty
-      }
+      forAll(result.changedProvinces)(cp => checkedAs[ChangedProvinceC](cp).changedUnaffiliatedHeroes shouldBe empty)
     }
   }
 
@@ -1904,7 +1881,7 @@ class ResolveBattleActionTest extends AnyFlatSpec with MockFactory with Matchers
       }
     fleeProvinceChange should be(defined)
 
-    val fleeProvinceCP = fleeProvinceChange.get.asInstanceOf[ChangedProvinceC]
+    val fleeProvinceCP = checkedAs[ChangedProvinceC](fleeProvinceChange.get)
     fleeProvinceCP.newIncomingArmies should have size 1
 
     val incomingArmy = fleeProvinceCP.newIncomingArmies.head

src/test/scala/net/eagle0/eagle/library/actions/impl/command/MarchCommandTest.scala

@@ -1,6 +1,6 @@
 package net.eagle0.eagle.library.actions.impl.command
 
-import net.eagle0.eagle.{BattalionId, FactionId, HeroId, ProvinceId, RoundId}
+import net.eagle0.eagle.{checkedAs, BattalionId, FactionId, HeroId, ProvinceId, RoundId}
 import net.eagle0.eagle.library.settings.{ActionVigorCost, MarchWisdomXp, TurnsToResolveConquest}
 import net.eagle0.eagle.library.EagleCommandException
 import net.eagle0.eagle.model.action_result.changed_province.concrete.ChangedProvinceC
@@ -122,7 +122,7 @@ class MarchCommandTest extends AnyFlatSpec with Matchers with BeforeAndAfterEach
     val result = action.immediateExecute
 
     result.shouldBe(a[ActionResultC])
-    val actionResult = result.asInstanceOf[ActionResultC]
+    val actionResult = checkedAs[ActionResultC](result)
     actionResult.actionResultType.shouldBe(MarchAction)
     actionResult.actingFactionId.should(contain(actingFactionId))
     actionResult.provinceId.should(contain(originProvinceId))
@@ -148,7 +148,7 @@ class MarchCommandTest extends AnyFlatSpec with Matchers with BeforeAndAfterEach
     val result = action.immediateExecute
 
     result.shouldBe(a[ActionResultC])
-    val actionResult = result.asInstanceOf[ActionResultC]
+    val actionResult = checkedAs[ActionResultC](result)
 
     actionResult.changedHeroes.shouldBe(
       Vector(
@@ -185,12 +185,13 @@ class MarchCommandTest extends AnyFlatSpec with Matchers with BeforeAndAfterEach
     val result = action.immediateExecute
 
     result.shouldBe(a[ActionResultC])
-    val actionResult = result.asInstanceOf[ActionResultC]
+    val actionResult = checkedAs[ActionResultC](result)
 
-    val originProvinceChange = actionResult.changedProvinces
-      .find(_.provinceId == originProvinceId)
-      .get
-      .asInstanceOf[ChangedProvinceC]
+    val originProvinceChange = checkedAs[ChangedProvinceC](
+      actionResult.changedProvinces
+        .find(_.provinceId == originProvinceId)
+        .get
+    )
     originProvinceChange.removedRulingFactionHeroIds.shouldBe(Vector(1, 27))
     originProvinceChange.removedBattalionIds.shouldBe(Vector(99, 98))
     originProvinceChange.goldDelta.shouldBe(Some(-3212))
@@ -222,11 +223,11 @@ class MarchCommandTest extends AnyFlatSpec with Matchers with BeforeAndAfterEach
     val result = action.immediateExecute
 
     result.shouldBe(a[ActionResultC])
-    val actionResult = result.asInstanceOf[ActionResultC]
+    val actionResult = checkedAs[ActionResultC](result)
 
     val actingProvinceChange = actionResult.changedProvinces
       .find(_.provinceId == actingProvince)
-      .map(_.asInstanceOf[ChangedProvinceC])
+      .map(checkedAs[ChangedProvinceC](_))
 
     actingProvinceChange.flatMap(_.setHasActed).shouldBe(Some(true))
   }
@@ -250,12 +251,13 @@ class MarchCommandTest extends AnyFlatSpec with Matchers with BeforeAndAfterEach
     val result = action.immediateExecute
 
     result.shouldBe(a[ActionResultC])
-    val actionResult = result.asInstanceOf[ActionResultC]
+    val actionResult = checkedAs[ActionResultC](result)
 
-    val destinationProvinceChange = actionResult.changedProvinces
-      .find(_.provinceId == destinationProvinceId)
-      .get
-      .asInstanceOf[ChangedProvinceC]
+    val destinationProvinceChange = checkedAs[ChangedProvinceC](
+      actionResult.changedProvinces
+        .find(_.provinceId == destinationProvinceId)
+        .get
+    )
     val incomingArmy              = destinationProvinceChange.newIncomingArmies.head
 
     incomingArmy.army.factionId.shouldBe(actingFactionId)

src/test/scala/net/eagle0/eagle/library/actions/impl/command/SendSuppliesCommandTest.scala

@@ -1,5 +1,6 @@
 package net.eagle0.eagle.library.actions.impl.command
 
+import net.eagle0.eagle.checkedAs
 import net.eagle0.eagle.library.settings.{
   ActionVigorCost,
   SendSuppliesWisdomXp,
@@ -208,7 +209,7 @@ class SendSuppliesCommandTest extends AnyFlatSpec with Matchers with BeforeAndAf
 
     // Cast to concrete type to access newIncomingShipments
     val concreteChange    =
-      destinationProvinceChange.get.asInstanceOf[ChangedProvinceC]
+      checkedAs[ChangedProvinceC](destinationProvinceChange.get)
     val incomingShipments = concreteChange.newIncomingShipments
     incomingShipments.should(have).size(1)
 

src/test/scala/net/eagle0/eagle/library/actions/impl/command/SwearBrotherhoodCommandTest.scala

@@ -1,6 +1,6 @@
 package net.eagle0.eagle.library.actions.impl.command
 
-import net.eagle0.eagle.{FactionId, GameId, HeroId, ProvinceId, RoundId}
+import net.eagle0.eagle.{checkedAs, FactionId, GameId, HeroId, ProvinceId, RoundId}
 import net.eagle0.eagle.library.actions.impl.common.ProtolessSequentialResultsAction
 import net.eagle0.eagle.library.settings.{AcceptBrotherhoodCharismaXp, SwearBrotherhoodCharismaXp}
 import net.eagle0.eagle.library.util.quest_fulfillment.QuestFulfillmentChecker
@@ -68,7 +68,7 @@ class SwearBrotherhoodCommandTest extends AnyFlatSpec with Matchers with BeforeA
     val result                                   = action.results.head
 
     result.shouldBe(a[ActionResultC])
-    val actionResult = result.asInstanceOf[ActionResultC]
+    val actionResult = checkedAs[ActionResultC](result)
     actionResult.actionResultType.shouldBe(SwearBrotherhood)
     actionResult.actingFactionId.should(contain(actingFactionId))
     actionResult.actingHeroId.should(contain(newBrotherHeroId))
@@ -92,7 +92,7 @@ class SwearBrotherhoodCommandTest extends AnyFlatSpec with Matchers with BeforeA
     val result                                   = action.results.head
 
     result.shouldBe(a[ActionResultC])
-    val actionResult = result.asInstanceOf[ActionResultC]
+    val actionResult = checkedAs[ActionResultC](result)
 
     actionResult.changedFactions.shouldBe(
       Vector(
@@ -140,7 +140,7 @@ class SwearBrotherhoodCommandTest extends AnyFlatSpec with Matchers with BeforeA
     val result                                   = action.results.head
 
     result.shouldBe(a[ActionResultC])
-    val actionResult = result.asInstanceOf[ActionResultC]
+    val actionResult = checkedAs[ActionResultC](result)
 
     val expectedLlmId =
       s"$currentRoundId swear brotherhood $newBrotherHeroId"

src/test/scala/net/eagle0/eagle/library/util/command_choice_helpers/AttackCommandChooserTest.scala

@@ -1,5 +1,6 @@
 package net.eagle0.eagle.library.util.command_choice_helpers
 
+import net.eagle0.eagle.checkedAs
 import net.eagle0.eagle.library.settings.{
   AlmsPaladinSupportMultiplier,
   AlmsSupportIncreasePerFood,
@@ -253,7 +254,7 @@ class AttackCommandChooserTest extends AnyFlatSpec with Matchers with BeforeAndA
     val gsWithoutDestinationRuler = gameState.copy(
       provinces = gameState.provinces.updated(
         destinationProvinceId,
-        gameState.provinces(destinationProvinceId).asInstanceOf[ProvinceC].copy(rulingFactionId = None)
+        checkedAs[ProvinceC](gameState.provinces(destinationProvinceId)).copy(rulingFactionId = None)
       )
     )
 
@@ -271,9 +272,10 @@ class AttackCommandChooserTest extends AnyFlatSpec with Matchers with BeforeAndA
       factions = gameState.factions
         .updated(
           destinationFactionId,
-          gameState
-            .factions(destinationFactionId)
-            .asInstanceOf[FactionC]
+          checkedAs[FactionC](
+            gameState
+              .factions(destinationFactionId)
+          )
             .copy(
               factionRelationships = Vector(
                 FactionRelationship(
@@ -286,9 +288,10 @@ class AttackCommandChooserTest extends AnyFlatSpec with Matchers with BeforeAndA
         )
         .updated(
           actingFactionId,
-          gameState
-            .factions(actingFactionId)
-            .asInstanceOf[FactionC]
+          checkedAs[FactionC](
+            gameState
+              .factions(actingFactionId)
+          )
             .copy(
               factionRelationships = Vector(
                 FactionRelationship(
@@ -315,9 +318,10 @@ class AttackCommandChooserTest extends AnyFlatSpec with Matchers with BeforeAndA
       factions = gameState.factions
         .updated(
           destinationFactionId,
-          gameState
-            .factions(destinationFactionId)
-            .asInstanceOf[FactionC]
+          checkedAs[FactionC](
+            gameState
+              .factions(destinationFactionId)
+          )
             .copy(
               factionRelationships = Vector(
                 FactionRelationship(
@@ -330,9 +334,10 @@ class AttackCommandChooserTest extends AnyFlatSpec with Matchers with BeforeAndA
         )
         .updated(
           actingFactionId,
-          gameState
-            .factions(actingFactionId)
-            .asInstanceOf[FactionC]
+          checkedAs[FactionC](
+            gameState
+              .factions(actingFactionId)
+          )
             .copy(
               factionRelationships = Vector(
                 FactionRelationship(

src/test/scala/net/eagle0/eagle/library/util/command_choice_helpers/CommandChoiceHelpersTest.scala

@@ -3,7 +3,7 @@ package net.eagle0.eagle.library.util.command_choice_helpers
 import scala.util.Random
 
 import net.eagle0.common.SeededRandom
-import net.eagle0.eagle.{BattalionId, FactionId, HeroId, ProvinceId}
+import net.eagle0.eagle.{checkedAs, BattalionId, FactionId, HeroId, ProvinceId}
 import net.eagle0.eagle.library.settings.{
   AlmsPaladinSupportMultiplier,
   AlmsSupportIncreasePerFood,
@@ -246,8 +246,7 @@ class CommandChoiceHelpersTest extends AnyFlatSpec with Matchers with BeforeAndA
     chosenCommand.get.actingFactionId shouldBe actingFid
     chosenCommand.get.actingProvinceId shouldBe 7
     chosenCommand.get.available shouldBe acs.head
-    chosenCommand.get.selected
-      .asInstanceOf[OrganizeTroopsSelected] shouldBe
+    checkedAs[OrganizeTroopsSelected](chosenCommand.get.selected) shouldBe
       OrganizeTroopsSelected(
         changedBattalions = Vector.empty,
         newBattalions = Vector(
@@ -886,7 +885,7 @@ class CommandChoiceHelpersTest extends AnyFlatSpec with Matchers with BeforeAndA
     choice.actingProvinceId shouldBe 5
 
     val marchSelectedCommand =
-      choice.selected.asInstanceOf[MarchSelected]
+      checkedAs[MarchSelected](choice.selected)
     marchSelectedCommand.marchingUnits should have size 25 // have 30, cap is 5
     (1 to 30) should contain allElementsOf (marchSelectedCommand.marchingUnits
       .map(_.heroId))
@@ -912,7 +911,7 @@ class CommandChoiceHelpersTest extends AnyFlatSpec with Matchers with BeforeAndA
     choice.actingProvinceId shouldBe 5
 
     val marchSelectedCommand =
-      choice.selected.asInstanceOf[MarchSelected]
+      checkedAs[MarchSelected](choice.selected)
     marchSelectedCommand.marchingUnits.map(
       _.heroId
     ) shouldBe (15 to 17).toVector
@@ -941,7 +940,7 @@ class CommandChoiceHelpersTest extends AnyFlatSpec with Matchers with BeforeAndA
     choice.actingProvinceId shouldBe 5
 
     val marchSelectedCommand =
-      choice.selected.asInstanceOf[MarchSelected]
+      checkedAs[MarchSelected](choice.selected)
     marchSelectedCommand.destinationProvinceId shouldBe 6
   }
 

src/test/scala/net/eagle0/eagle/library/util/command_choice_helpers/FulfillQuestsCommandSelectorTest.scala

@@ -1,7 +1,7 @@
 package net.eagle0.eagle.library.util.command_choice_helpers
 
 import net.eagle0.common.SeededRandom
-import net.eagle0.eagle.{FactionId, HeroId, ProvinceId}
+import net.eagle0.eagle.{checkedAs, FactionId, HeroId, ProvinceId}
 import net.eagle0.eagle.library.settings.MinimumTrustToOfferTruce
 import net.eagle0.eagle.library.util.CommandSelection
 import net.eagle0.eagle.model.state.{GameType, RoundPhase}
@@ -283,9 +283,10 @@ class FulfillQuestsCommandSelectorTest extends AnyFlatSpec with Matchers with Be
     val lowTrustGameState = gameState.copy(
       factions = gameState.factions.updated(
         actingFactionId,
-        gameState
-          .factions(actingFactionId)
-          .asInstanceOf[FactionC]
+        checkedAs[FactionC](
+          gameState
+            .factions(actingFactionId)
+        )
           .copy(
             factionRelationships = Vector(
               FactionRelationship(
@@ -380,9 +381,10 @@ class FulfillQuestsCommandSelectorTest extends AnyFlatSpec with Matchers with Be
       ),
       factions = gameState.factions.updated(
         actingFactionId,
-        gameState
-          .factions(actingFactionId)
-          .asInstanceOf[FactionC]
+        checkedAs[FactionC](
+          gameState
+            .factions(actingFactionId)
+        )
           .copy(
             factionRelationships = Vector(
               FactionRelationship(
@@ -458,9 +460,10 @@ class FulfillQuestsCommandSelectorTest extends AnyFlatSpec with Matchers with Be
       ),
       factions = gameState.factions.updated(
         actingFactionId,
-        gameState
-          .factions(actingFactionId)
-          .asInstanceOf[FactionC]
+        checkedAs[FactionC](
+          gameState
+            .factions(actingFactionId)
+        )
           .copy(
             factionRelationships = Vector(
               FactionRelationship(
@@ -525,9 +528,10 @@ class FulfillQuestsCommandSelectorTest extends AnyFlatSpec with Matchers with Be
       factions = gameState.factions
         .updated(
           actingFactionId,
-          gameState
-            .factions(actingFactionId)
-            .asInstanceOf[FactionC]
+          checkedAs[FactionC](
+            gameState
+              .factions(actingFactionId)
+          )
             .copy(
               factionRelationships = Vector(
                 FactionRelationship(
@@ -550,9 +554,10 @@ class FulfillQuestsCommandSelectorTest extends AnyFlatSpec with Matchers with Be
         )
         .updated(
           105,
-          gameState
-            .factions(105)
-            .asInstanceOf[FactionC]
+          checkedAs[FactionC](
+            gameState
+              .factions(105)
+          )
             .copy(
               factionRelationships = Vector(
                 FactionRelationship(

src/test/scala/net/eagle0/eagle/library/util/command_choice_helpers/quest_command_selectors/DevelopProvincesQuestCommandChooserTest.scala

@@ -16,6 +16,7 @@ import net.eagle0.eagle.model.state.quest.{DevelopProvincesQuest, ImproveAgricul
 import net.eagle0.eagle.model.state.run_status.RunStatus
 import org.scalatest.flatspec.AnyFlatSpec
 import org.scalatest.matchers.should.Matchers
+import org.scalatest.Inside.inside
 
 class DevelopProvincesQuestCommandChooserTest extends AnyFlatSpec with Matchers {
 
@@ -177,12 +178,14 @@ class DevelopProvincesQuestCommandChooserTest extends AnyFlatSpec with Matchers
     )
 
     result shouldBe defined
-    val selected   = result.get.selected.asInstanceOf[IssueOrdersSelected]
-    // province1 and province2 should be switched (non-hostile first), province3 kept as Mobilize
-    val developIds = selected.newOrders.filter(_.orderType == ProvinceOrderType.Develop).map(_.provinceId).toSet
-    developIds should contain(province1Id)
-    developIds should contain(province2Id)
-    developIds should not contain enemyProvinceId
+    inside(result.get.selected) {
+      case selected: IssueOrdersSelected =>
+        // province1 and province2 should be switched (non-hostile first), province3 kept as Mobilize
+        val developIds = selected.newOrders.filter(_.orderType == ProvinceOrderType.Develop).map(_.provinceId).toSet
+        developIds.should(contain(province1Id))
+        developIds.should(contain(province2Id))
+        developIds.contains(enemyProvinceId).shouldBe(false)
+    }
   }
 
   it should "include hostile-neighbor provinces when needed" in {
@@ -214,8 +217,10 @@ class DevelopProvincesQuestCommandChooserTest extends AnyFlatSpec with Matchers
     )
 
     result shouldBe defined
-    val selected = result.get.selected.asInstanceOf[IssueOrdersSelected]
-    selected.newOrders.count(_.orderType == ProvinceOrderType.Develop) shouldBe 2
+    inside(result.get.selected) {
+      case selected: IssueOrdersSelected =>
+        selected.newOrders.count(_.orderType == ProvinceOrderType.Develop).shouldBe(2)
+    }
   }
 
   it should "return None when IssueOrders is not available" in {

src/test/scala/net/eagle0/eagle/library/util/command_choice_helpers/quest_command_selectors/MobilizeProvincesQuestCommandChooserTest.scala

@@ -16,6 +16,7 @@ import net.eagle0.eagle.model.state.quest.{DevelopProvincesQuest, MobilizeProvin
 import net.eagle0.eagle.model.state.run_status.RunStatus
 import org.scalatest.flatspec.AnyFlatSpec
 import org.scalatest.matchers.should.Matchers
+import org.scalatest.Inside.inside
 
 class MobilizeProvincesQuestCommandChooserTest extends AnyFlatSpec with Matchers {
 
@@ -158,10 +159,12 @@ class MobilizeProvincesQuestCommandChooserTest extends AnyFlatSpec with Matchers
     )
 
     result shouldBe defined
-    val selected    = result.get.selected.asInstanceOf[IssueOrdersSelected]
-    val mobilizeIds = selected.newOrders.filter(_.orderType == ProvinceOrderType.Mobilize).map(_.provinceId).toSet
-    // province2 (hostile neighbor) should be picked first
-    mobilizeIds should contain(province2Id)
+    inside(result.get.selected) {
+      case selected: IssueOrdersSelected =>
+        val mobilizeIds = selected.newOrders.filter(_.orderType == ProvinceOrderType.Mobilize).map(_.provinceId).toSet
+        // province2 (hostile neighbor) should be picked first
+        mobilizeIds.should(contain(province2Id))
+    }
   }
 
   it should "switch provinces to Mobilize when quest conditions are met" in {
@@ -175,11 +178,13 @@ class MobilizeProvincesQuestCommandChooserTest extends AnyFlatSpec with Matchers
     )
 
     result shouldBe defined
-    val selected = result.get.selected.asInstanceOf[IssueOrdersSelected]
-    selected.newOrders.count(_.orderType == ProvinceOrderType.Mobilize) shouldBe 2
-    // The Develop province should not be switched
-    selected.newOrders.find(_.provinceId == province3Id).get.orderType shouldBe ProvinceOrderType.Develop
-    result.get.reason shouldBe "fulfill MobilizeProvinces quest"
+    inside(result.get.selected) {
+      case selected: IssueOrdersSelected =>
+        selected.newOrders.count(_.orderType == ProvinceOrderType.Mobilize).shouldBe(2)
+        // The Develop province should not be switched
+        selected.newOrders.find(_.provinceId == province3Id).get.orderType.shouldBe(ProvinceOrderType.Develop)
+    }
+    result.get.reason.shouldBe("fulfill MobilizeProvinces quest")
   }
 
   it should "return None when already enough provinces are mobilizing" in {