refactor: NCS-22 NCS-23 reworked modules and tests (#17)

Reviewed-on: #17

modules/io/src/test/scala/de/nowchess/io/fen/FenExporterTest.scala

@@ -0,0 +1,104 @@
+package de.nowchess.io.fen
+
+import de.nowchess.api.board.*
+import de.nowchess.api.game.GameContext
+import de.nowchess.api.move.Move
+import org.scalatest.funsuite.AnyFunSuite
+import org.scalatest.matchers.should.Matchers
+
+class FenExporterTest extends AnyFunSuite with Matchers:
+
+  private def context(
+    piecePlacement: String,
+    turn: Color,
+    castlingRights: CastlingRights,
+    enPassantSquare: Option[Square],
+    halfMoveClock: Int,
+    moveCount: Int
+  ): GameContext =
+    val board = FenParser.parseBoard(piecePlacement).getOrElse(
+      fail(s"Invalid test board FEN: $piecePlacement")
+    )
+    val dummyMove = Move(Square(File.A, Rank.R2), Square(File.A, Rank.R3))
+    GameContext(
+      board = board,
+      turn = turn,
+      castlingRights = castlingRights,
+      enPassantSquare = enPassantSquare,
+      halfMoveClock = halfMoveClock,
+      moves = List.fill(moveCount)(dummyMove)
+    )
+
+  test("exportGameContextToFen handles initial and typical developed position"):
+    FenExporter.gameContextToFen(GameContext.initial) shouldBe
+      "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"
+
+    val gameContext = context(
+      piecePlacement = "rnbqkbnr/pppppppp/8/8/4P3/8/PPPP1PPP/RNBQKBNR",
+      turn = Color.Black,
+      castlingRights = CastlingRights.All,
+      enPassantSquare = Some(Square(File.E, Rank.R3)),
+      halfMoveClock = 0,
+      moveCount = 0
+    )
+    FenExporter.gameContextToFen(gameContext) shouldBe
+      "rnbqkbnr/pppppppp/8/8/4P3/8/PPPP1PPP/RNBQKBNR b KQkq e3 0 1"
+
+  test("export handles castling rights variants and en-passant with counters"):
+    val noCastling = context(
+      piecePlacement = "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR",
+      turn = Color.White,
+      castlingRights = CastlingRights.None,
+      enPassantSquare = None,
+      halfMoveClock = 0,
+      moveCount = 0
+    )
+    FenExporter.gameContextToFen(noCastling) shouldBe
+      "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w - - 0 1"
+
+    val partialCastling = context(
+      piecePlacement = "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR",
+      turn = Color.White,
+      castlingRights = CastlingRights(
+        whiteKingSide = true,
+        whiteQueenSide = false,
+        blackKingSide = false,
+        blackQueenSide = true
+      ),
+      enPassantSquare = None,
+      halfMoveClock = 5,
+      moveCount = 4
+    )
+    FenExporter.gameContextToFen(partialCastling) shouldBe
+      "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w Kq - 5 3"
+
+    val withEnPassant = context(
+      piecePlacement = "rnbqkbnr/pp1ppppp/8/2pP4/8/8/PPPP1PPP/RNBQKBNR",
+      turn = Color.White,
+      castlingRights = CastlingRights.All,
+      enPassantSquare = Some(Square(File.C, Rank.R6)),
+      halfMoveClock = 2,
+      moveCount = 4
+    )
+    FenExporter.gameContextToFen(withEnPassant) shouldBe
+      "rnbqkbnr/pp1ppppp/8/2pP4/8/8/PPPP1PPP/RNBQKBNR w KQkq c6 2 3"
+
+  test("halfMoveClock round-trips through FEN export and import"):
+    val gameContext = GameContext(
+      board = Board.initial,
+      turn = Color.White,
+      castlingRights = CastlingRights.All,
+      enPassantSquare = None,
+      halfMoveClock = 42,
+      moves = List.empty
+    )
+    val fen = FenExporter.gameContextToFen(gameContext)
+    FenParser.parseFen(fen) match
+      case Right(ctx) => ctx.halfMoveClock shouldBe 42
+      case Left(err)  => fail(s"FEN parsing failed: $err")
+
+  test("exportGameContext forwards to gameContextToFen"):
+    val ctx = GameContext.initial
+
+    FenExporter.exportGameContext(ctx) shouldBe FenExporter.gameContextToFen(ctx)
+

modules/io/src/test/scala/de/nowchess/io/fen/FenParserTest.scala

@@ -0,0 +1,55 @@
+package de.nowchess.io.fen
+
+import de.nowchess.api.board.*
+import org.scalatest.funsuite.AnyFunSuite
+import org.scalatest.matchers.should.Matchers
+
+class FenParserTest extends AnyFunSuite with Matchers:
+
+  test("parseBoard parses canonical positions and supports round-trip"):
+    val initial = "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR"
+    val empty = "8/8/8/8/8/8/8/8"
+    val partial = "8/8/4k3/8/4K3/8/8/8"
+
+    FenParser.parseBoard(initial).map(_.pieceAt(Square(File.E, Rank.R2))) shouldBe Some(Some(Piece.WhitePawn))
+    FenParser.parseBoard(initial).map(_.pieceAt(Square(File.E, Rank.R8))) shouldBe Some(Some(Piece.BlackKing))
+    FenParser.parseBoard(empty).map(_.pieces.size) shouldBe Some(0)
+    FenParser.parseBoard(partial).map(_.pieceAt(Square(File.E, Rank.R6))) shouldBe Some(Some(Piece.BlackKing))
+
+    FenParser.parseBoard(initial).map(FenExporter.boardToFen) shouldBe Some(initial)
+    FenParser.parseBoard(empty).map(FenExporter.boardToFen) shouldBe Some(empty)
+
+  test("parseFen parses full state for common valid inputs"):
+    FenParser.parseFen("rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1").fold(_ => fail(), ctx =>
+      ctx.turn shouldBe Color.White
+      ctx.castlingRights.whiteKingSide shouldBe true
+      ctx.enPassantSquare shouldBe None
+      ctx.halfMoveClock shouldBe 0
+    )
+
+    FenParser.parseFen("rnbqkbnr/pppppppp/8/8/4P3/8/PPPP1PPP/RNBQKBNR b KQkq e3 0 1").fold(_ => fail(), ctx =>
+      ctx.turn shouldBe Color.Black
+      ctx.enPassantSquare shouldBe Some(Square(File.E, Rank.R3))
+    )
+
+    FenParser.parseFen("rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w - - 0 1").fold(_ => fail(), ctx =>
+      ctx.castlingRights.whiteKingSide shouldBe false
+      ctx.castlingRights.blackQueenSide shouldBe false
+    )
+
+  test("parseFen rejects invalid color and castling tokens"):
+    FenParser.parseFen("rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR x KQkq - 0 1").isLeft shouldBe true
+    FenParser.parseFen("rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w XYZ - 0 1").isLeft shouldBe true
+
+  test("importGameContext returns Right for valid and Left for invalid FEN"):
+    val fen = "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"
+    FenParser.importGameContext(fen).isRight shouldBe true
+    FenParser.importGameContext("invalid fen string").isLeft shouldBe true
+
+  test("parseBoard rejects malformed board shapes and invalid piece symbols"):
+    FenParser.parseBoard("8/8/8/8/8/8/8") shouldBe None
+    FenParser.parseBoard("9/8/8/8/8/8/8/8") shouldBe None
+    FenParser.parseBoard("8p/8/8/8/8/8/8/8") shouldBe None
+    FenParser.parseBoard("7/8/8/8/8/8/8/8") shouldBe None
+    FenParser.parseBoard("8/8/8/8/8/8/8/7X") shouldBe None
+

modules/io/src/test/scala/de/nowchess/io/pgn/PgnExporterTest.scala

@@ -0,0 +1,108 @@
+package de.nowchess.io.pgn
+
+import de.nowchess.api.board.*
+import de.nowchess.api.game.GameContext
+import de.nowchess.api.move.{Move, MoveType, PromotionPiece}
+import org.scalatest.funsuite.AnyFunSuite
+import org.scalatest.matchers.should.Matchers
+
+class PgnExporterTest extends AnyFunSuite with Matchers:
+
+  test("exportGame renders headers and basic move text"):
+    val headers = Map("Event" -> "Test", "White" -> "A", "Black" -> "B")
+    val emptyPgn = PgnExporter.exportGame(headers, List.empty)
+    emptyPgn.contains("[Event \"Test\"]") shouldBe true
+    emptyPgn.contains("[White \"A\"]") shouldBe true
+    emptyPgn.contains("[Black \"B\"]") shouldBe true
+
+    val moves = List(Move(Square(File.E, Rank.R2), Square(File.E, Rank.R4), MoveType.Normal()))
+    PgnExporter.exportGame(headers, moves).contains("1. e4") shouldBe true
+
+  test("exportGame renders castling grouping and result markers"):
+    PgnExporter.exportGame(Map("Event" -> "Test"), List(Move(Square(File.E, Rank.R1), Square(File.G, Rank.R1), MoveType.CastleKingside))) should include("O-O")
+    PgnExporter.exportGame(Map("Event" -> "Test"), List(Move(Square(File.E, Rank.R1), Square(File.C, Rank.R1), MoveType.CastleQueenside))) should include("O-O-O")
+
+    val seq = List(
+      Move(Square(File.E, Rank.R2), Square(File.E, Rank.R4), MoveType.Normal()),
+      Move(Square(File.C, Rank.R7), Square(File.C, Rank.R5), MoveType.Normal()),
+      Move(Square(File.G, Rank.R1), Square(File.F, Rank.R3), MoveType.Normal())
+    )
+    val grouped = PgnExporter.exportGame(Map("Result" -> "1-0"), seq)
+    grouped should include("1. e4 c5")
+    grouped should include("2. Nf3")
+
+    val oneMove = List(Move(Square(File.E, Rank.R2), Square(File.E, Rank.R4), MoveType.Normal()))
+    PgnExporter.exportGame(Map.empty, oneMove) shouldBe "1. e4 *"
+    PgnExporter.exportGame(Map("Result" -> "1/2-1/2"), oneMove) should endWith("1/2-1/2")
+
+  test("exportGame handles promotion suffixes and normal move formatting"):
+    List(
+      PromotionPiece.Queen -> "=Q",
+      PromotionPiece.Rook -> "=R",
+      PromotionPiece.Bishop -> "=B",
+      PromotionPiece.Knight -> "=N"
+    ).foreach { (piece, suffix) =>
+      val move = Move(Square(File.E, Rank.R7), Square(File.E, Rank.R8), MoveType.Promotion(piece))
+      PgnExporter.exportGame(Map.empty, List(move)) should include(s"e8$suffix")
+    }
+
+    val normal = PgnExporter.exportGame(Map.empty, List(Move(Square(File.E, Rank.R2), Square(File.E, Rank.R4), MoveType.Normal())))
+    normal should include("e4")
+    normal should not include "="
+
+  test("exportGameContext preserves moves and default headers"):
+    val moves = List(
+      Move(Square(File.E, Rank.R2), Square(File.E, Rank.R4), MoveType.Normal()),
+      Move(Square(File.E, Rank.R7), Square(File.E, Rank.R5), MoveType.Normal())
+    )
+    val withMoves = PgnExporter.exportGameContext(GameContext.initial.copy(moves = moves))
+    withMoves.contains("e4") shouldBe true
+    withMoves.contains("e5") shouldBe true
+
+    val empty = PgnExporter.exportGameContext(GameContext.initial)
+    empty.contains("[Event") shouldBe true
+    empty.contains("*") shouldBe true
+
+  private def sq(alg: String): Square =
+    Square.fromAlgebraic(alg).getOrElse(fail(s"Invalid square in test: $alg"))
+
+  test("exportGame emits notation for all normal piece types and captures"):
+    val moves = List(
+      Move(sq("e2"), sq("e4")),
+      Move(sq("a7"), sq("a6")),
+      Move(sq("g1"), sq("f3")),
+      Move(sq("b7"), sq("b6")),
+      Move(sq("f1"), sq("b5"), MoveType.Normal(true)),
+      Move(sq("g8"), sq("f6")),
+      Move(sq("a1"), sq("a8"), MoveType.Normal(true)),
+      Move(sq("c7"), sq("c6")),
+      Move(sq("d1"), sq("d7"), MoveType.Normal(true)),
+      Move(sq("d8"), sq("d7"), MoveType.Normal(true)),
+      Move(sq("e1"), sq("e2"), MoveType.Normal(true))
+    )
+
+    val pgn = PgnExporter.exportGame(Map("Result" -> "*"), moves)
+
+    pgn should include("e4")
+    pgn should include("Nf3")
+    pgn should include("Bxb5")
+    pgn should include("Rxa8")
+    pgn should include("Qxd7")
+    pgn should include("Kxe2")
+
+  test("exportGame emits en-passant and promotion capture notation"):
+    val enPassant = Move(sq("e2"), sq("d3"), MoveType.EnPassant)
+    val promotionCapture = Move(sq("e7"), sq("f8"), MoveType.Promotion(PromotionPiece.Queen))
+    val pawnCapture = Move(sq("e2"), sq("d3"), MoveType.Normal(isCapture = true))
+    val promotionQuietSetup = Move(sq("e8"), sq("e7"))
+    val promotionQuiet = Move(sq("e2"), sq("e8"), MoveType.Promotion(PromotionPiece.Queen))
+
+    val pgn = PgnExporter.exportGame(Map.empty, List(enPassant, promotionCapture))
+    val pawnCapturePgn = PgnExporter.exportGame(Map.empty, List(pawnCapture))
+    val quietPromotionPgn = PgnExporter.exportGame(Map.empty, List(promotionQuietSetup, promotionQuiet))
+
+    pgn should include("exd3")
+    pgn should include("exf8=Q")
+    pawnCapturePgn should include("exd3")
+    quietPromotionPgn should include("e8=Q")
+

modules/io/src/test/scala/de/nowchess/io/pgn/PgnParserTest.scala

@@ -0,0 +1,131 @@
+package de.nowchess.io.pgn
+
+import de.nowchess.api.board.*
+import de.nowchess.api.move.{MoveType, PromotionPiece}
+import de.nowchess.api.game.GameContext
+import de.nowchess.io.fen.FenParser
+import org.scalatest.funsuite.AnyFunSuite
+import org.scalatest.matchers.should.Matchers
+
+class PgnParserTest extends AnyFunSuite with Matchers:
+
+  test("parsePgn handles headers standard sequences captures castling and skipped tokens"):
+    val headerOnly = """[Event "Test Game"]
+[White "Alice"]
+[Black "Bob"]
+[Result "1-0"]"""
+    val onlyHeaders = PgnParser.parsePgn(headerOnly)
+    onlyHeaders.isDefined shouldBe true
+    onlyHeaders.get.headers("Event") shouldBe "Test Game"
+    onlyHeaders.get.headers("White") shouldBe "Alice"
+
+    val simple = PgnParser.parsePgn("""[Event "Test"]
+
+1. e4 e5 2. Nf3 Nc6""")
+    simple.map(_.moves.length) shouldBe Some(4)
+
+    val capture = PgnParser.parsePgn("""[Event "Test"]
+
+1. Nf3 e5 2. Nxe5""")
+    capture.map(_.moves.length) shouldBe Some(3)
+    capture.get.moves(2).to shouldBe Square(File.E, Rank.R5)
+
+    val whiteKs = PgnParser.parsePgn("""[Event "Test"]
+
+1. e4 e5 2. Nf3 Nc6 3. Bc4 Bc5 4. O-O""").get.moves.last
+    whiteKs.moveType shouldBe MoveType.CastleKingside
+    whiteKs.from shouldBe Square(File.E, Rank.R1)
+    whiteKs.to shouldBe Square(File.G, Rank.R1)
+
+    val whiteQs = PgnParser.parsePgn("""[Event "Test"]
+
+1. d4 d5 2. Nc3 Nc6 3. Bf4 Bf5 4. Qd2 Qd7 5. O-O-O""").get.moves.last
+    whiteQs.moveType shouldBe MoveType.CastleQueenside
+    whiteQs.from shouldBe Square(File.E, Rank.R1)
+    whiteQs.to shouldBe Square(File.C, Rank.R1)
+
+    val blackKs = PgnParser.parsePgn("""[Event "Test"]
+
+1. e4 e5 2. Nf3 Nf6 3. Bc4 Be7 4. O-O O-O""").get.moves.last
+    blackKs.moveType shouldBe MoveType.CastleKingside
+    blackKs.from shouldBe Square(File.E, Rank.R8)
+
+    val blackQs = PgnParser.parsePgn("""[Event "Test"]
+
+1. d4 d5 2. Nc3 Nc6 3. Bf4 Bf5 4. Qd2 Qd7 5. O-O-O O-O-O""").get.moves.last
+    blackQs.moveType shouldBe MoveType.CastleQueenside
+    blackQs.from shouldBe Square(File.E, Rank.R8)
+    blackQs.to shouldBe Square(File.C, Rank.R8)
+
+    PgnParser.parsePgn("""[Event "Test"]
+
+1. e4 e5 1-0""").map(_.moves.length) shouldBe Some(2)
+    PgnParser.parsePgn("""[Event "Test"]
+
+1. e4 INVALID e5""").map(_.moves.length) shouldBe Some(2)
+
+  test("parseAlgebraicMove resolves pawn knight king and disambiguation cases"):
+    val board = Board.initial
+    PgnParser.parseAlgebraicMove("e4", GameContext.initial.withBoard(board), Color.White).get.to shouldBe Square(File.E, Rank.R4)
+    PgnParser.parseAlgebraicMove("Nf3", GameContext.initial.withBoard(board), Color.White).get.to shouldBe Square(File.F, Rank.R3)
+
+    val rookPieces: Map[Square, Piece] = Map(
+      Square(File.A, Rank.R1) -> Piece(Color.White, PieceType.Rook),
+      Square(File.H, Rank.R1) -> Piece(Color.White, PieceType.Rook),
+      Square(File.E, Rank.R1) -> Piece(Color.White, PieceType.King),
+      Square(File.E, Rank.R8) -> Piece(Color.Black, PieceType.King)
+    )
+    val rankPieces: Map[Square, Piece] = Map(
+      Square(File.A, Rank.R1) -> Piece(Color.White, PieceType.Rook),
+      Square(File.A, Rank.R4) -> Piece(Color.White, PieceType.Rook),
+      Square(File.E, Rank.R1) -> Piece(Color.White, PieceType.King),
+      Square(File.E, Rank.R8) -> Piece(Color.Black, PieceType.King)
+    )
+    PgnParser.parseAlgebraicMove("Rad1", GameContext.initial.withBoard(Board(rookPieces)), Color.White).get.from shouldBe Square(File.A, Rank.R1)
+    PgnParser.parseAlgebraicMove("R1a3", GameContext.initial.withBoard(Board(rankPieces)), Color.White).get.from shouldBe Square(File.A, Rank.R1)
+
+    val kingBoard = FenParser.parseBoard("4k3/8/8/8/8/8/8/4K3").get
+    val king = PgnParser.parseAlgebraicMove("Ke2", GameContext.initial.withBoard(kingBoard), Color.White)
+    king.isDefined shouldBe true
+    king.get.from shouldBe Square(File.E, Rank.R1)
+    king.get.to shouldBe Square(File.E, Rank.R2)
+
+  test("parseAlgebraicMove handles all promotion targets"):
+    val board = FenParser.parseBoard("8/4P3/4k3/8/8/8/8/8").get
+    PgnParser.parseAlgebraicMove("e7e8=Q", GameContext.initial.withBoard(board), Color.White).get.moveType shouldBe MoveType.Promotion(PromotionPiece.Queen)
+    PgnParser.parseAlgebraicMove("e7e8=R", GameContext.initial.withBoard(board), Color.White).get.moveType shouldBe MoveType.Promotion(PromotionPiece.Rook)
+    PgnParser.parseAlgebraicMove("e7e8=B", GameContext.initial.withBoard(board), Color.White).get.moveType shouldBe MoveType.Promotion(PromotionPiece.Bishop)
+    PgnParser.parseAlgebraicMove("e7e8=N", GameContext.initial.withBoard(board), Color.White).get.moveType shouldBe MoveType.Promotion(PromotionPiece.Knight)
+
+  test("importGameContext accepts valid and empty PGN"):
+    val pgn = """[Event "Test"]
+
+1. e4 e5"""
+    PgnParser.importGameContext(pgn).isRight shouldBe true
+    PgnParser.importGameContext("").isRight shouldBe true
+
+  test("parser edge cases: uppercase token hint chars and promotion mismatch handling"):
+    PgnParser.parseAlgebraicMove("E5", GameContext.initial, Color.White) shouldBe None
+    PgnParser.parseAlgebraicMove("N?f3", GameContext.initial, Color.White).get.to shouldBe Square(File.F, Rank.R3)
+    PgnParser.extractPromotion("e7e8=X") shouldBe None
+
+    val board = FenParser.parseBoard("8/4P3/4k3/8/8/8/8/8").get
+    PgnParser.parseAlgebraicMove("e8", GameContext.initial.withBoard(board), Color.White) shouldBe None
+
+  test("parseAlgebraicMove rejects too-short notation and invalid piece letters"):
+    val initial = GameContext.initial
+
+    PgnParser.parseAlgebraicMove("e", initial, Color.White) shouldBe None
+    PgnParser.parseAlgebraicMove("Xe5", initial, Color.White) shouldBe None
+
+  test("parseAlgebraicMove rejects notation with invalid promotion piece"):
+    val board = FenParser.parseBoard("8/4P3/4k3/8/8/8/8/8").getOrElse(fail("valid board expected"))
+    val context = GameContext.initial.withBoard(board)
+
+    PgnParser.parseAlgebraicMove("e7e8=X", context, Color.White) shouldBe None
+
+  test("parsePgn silently skips unknown tokens"):
+    val parsed = PgnParser.parsePgn("1. e4 ??? e5")
+
+    parsed.map(_.moves.size) shouldBe Some(2)
+

modules/io/src/test/scala/de/nowchess/io/pgn/PgnValidatorTest.scala

@@ -0,0 +1,58 @@
+package de.nowchess.io.pgn
+
+import de.nowchess.api.board.*
+import de.nowchess.api.move.MoveType
+import org.scalatest.funsuite.AnyFunSuite
+import org.scalatest.matchers.should.Matchers
+
+class PgnValidatorTest extends AnyFunSuite with Matchers:
+
+  test("validatePgn accepts valid games including castling and result tokens"):
+    val pgn =
+      """[Event "Test"]
+
+1. e4 e5 2. Nf3 Nc6
+"""
+    val valid = PgnParser.validatePgn(pgn)
+    valid.isRight shouldBe true
+    valid.toOption.get.moves.length shouldBe 4
+    valid.toOption.get.moves.head.from shouldBe Square(File.E, Rank.R2)
+
+    val withResult = PgnParser.validatePgn("""[Event "Test"]
+
+1. e4 e5 1-0
+""")
+    withResult.map(_.moves.length) shouldBe Right(2)
+
+    val kCastle = PgnParser.validatePgn("""[Event "Test"]
+
+1. e4 e5 2. Nf3 Nc6 3. Bc4 Bc5 4. O-O
+""")
+    kCastle.map(_.moves.last.moveType) shouldBe Right(MoveType.CastleKingside)
+
+    val qCastle = PgnParser.validatePgn("""[Event "Test"]
+
+1. d4 d5 2. Nc3 Nc6 3. Bf4 Bf5 4. Qd2 Qd7 5. O-O-O
+""")
+    qCastle.map(_.moves.last.moveType) shouldBe Right(MoveType.CastleQueenside)
+
+  test("validatePgn rejects impossible illegal and garbage tokens"):
+    PgnParser.validatePgn("""[Event "Test"]
+
+1. Qd4
+""").isLeft shouldBe true
+
+    PgnParser.validatePgn("""[Event "Test"]
+
+1. O-O
+""").isLeft shouldBe true
+
+    PgnParser.validatePgn("""[Event "Test"]
+
+1. e4 GARBAGE e5
+""").isLeft shouldBe true
+
+  test("validatePgn accepts empty move text and minimal valid header"):
+    PgnParser.validatePgn("[Event \"Test\"]\n[White \"A\"]\n[Black \"B\"]\n").map(_.moves) shouldBe Right(List.empty)
+    PgnParser.validatePgn("[Event \"T\"]\n\n1. e4").isRight shouldBe true
+