mchess-server/chess/board_castling_test.go

package chess

import (
	"mchess_server/types"
	"testing"

	"github.com/stretchr/testify/assert"
)

func Test_Board_WhiteCastlesLeft(t *testing.T) {
	board := newBoard()

	board.position[types.Coordinate{Col: 5, Row: 1}] = King{Color: types.White}
	board.position[types.Coordinate{Col: 1, Row: 1}] = Rook{Color: types.White}

	castling := types.Move{
		StartSquare: types.Coordinate{Col: 5, Row: 1},
		EndSquare:   types.Coordinate{Col: 3, Row: 1},
		ColorMoved:  types.White,
	}

	valid, _ := board.CheckAndPlay(&castling)

	assert.True(t, valid)
}

func Test_Board_WhiteCastlesRight(t *testing.T) {
	board := newBoard()

	board.position[types.Coordinate{Col: 5, Row: 1}] = King{Color: types.White}
	board.position[types.Coordinate{Col: 8, Row: 1}] = Rook{Color: types.White}

	castling := types.Move{
		StartSquare: types.Coordinate{Col: 5, Row: 1},
		EndSquare:   types.Coordinate{Col: 7, Row: 1},
		ColorMoved:  types.White,
	}

	valid, _ := board.CheckAndPlay(&castling)

	assert.True(t, valid)
}

func Test_Board_BlackCastlesLeft(t *testing.T) {
	board := newBoard()
	board.colorToMove = types.Black

	board.position[types.Coordinate{Col: 5, Row: 8}] = King{Color: types.Black}
	board.position[types.Coordinate{Col: 1, Row: 8}] = Rook{Color: types.Black}

	castling := types.Move{
		StartSquare: types.Coordinate{Col: 5, Row: 8},
		EndSquare:   types.Coordinate{Col: 3, Row: 8},
		ColorMoved:  types.Black,
	}

	valid, _ := board.CheckAndPlay(&castling)

	assert.True(t, valid)
}

func Test_Board_BlackCastlesRight(t *testing.T) {
	board := newBoard()
	board.colorToMove = types.Black

	board.position[types.Coordinate{Col: 5, Row: 8}] = King{Color: types.Black}
	board.position[types.Coordinate{Col: 8, Row: 8}] = Rook{Color: types.Black}

	castling := types.Move{
		StartSquare: types.Coordinate{Col: 5, Row: 8},
		EndSquare:   types.Coordinate{Col: 7, Row: 8},
		ColorMoved:  types.Black,
	}

	valid, _ := board.CheckAndPlay(&castling)

	assert.True(t, valid)
}

func Test_Board_WhiteCastlesLeft_QueenCoversSquareInBetween(t *testing.T) {
	board := newBoard()

	board.position[types.Coordinate{Col: 5, Row: 1}] = King{Color: types.White}
	board.position[types.Coordinate{Col: 1, Row: 1}] = Rook{Color: types.White}
	board.position[types.Coordinate{Col: 4, Row: 5}] = Queen{Color: types.Black}

	castling := types.Move{
		StartSquare: types.Coordinate{Col: 5, Row: 1},
		EndSquare:   types.Coordinate{Col: 3, Row: 1},
		ColorMoved:  types.White,
	}

	valid, _ := board.CheckAndPlay(&castling)

	assert.False(t, valid)
}

func Test_Board_WhiteCastlesRight_QueenCoversSquareInBetween(t *testing.T) {
	board := newBoard()

	board.position[types.Coordinate{Col: 5, Row: 1}] = King{Color: types.White}
	board.position[types.Coordinate{Col: 8, Row: 1}] = Rook{Color: types.White}
	board.position[types.Coordinate{Col: 6, Row: 5}] = Queen{Color: types.Black}

	castling := types.Move{
		StartSquare: types.Coordinate{Col: 5, Row: 1},
		EndSquare:   types.Coordinate{Col: 7, Row: 1},
		ColorMoved:  types.White,
	}

	valid, _ := board.CheckAndPlay(&castling)

	assert.False(t, valid)
}

func Test_Board_WhiteCastlesLeft_KingInCheck(t *testing.T) {
	board := newBoard()

	board.position[types.Coordinate{Col: 5, Row: 1}] = King{Color: types.White}
	board.position[types.Coordinate{Col: 1, Row: 1}] = Rook{Color: types.White}
	board.position[types.Coordinate{Col: 5, Row: 5}] = Queen{Color: types.Black}

	castling := types.Move{
		StartSquare: types.Coordinate{Col: 5, Row: 1},
		EndSquare:   types.Coordinate{Col: 3, Row: 1},
		ColorMoved:  types.White,
	}

	valid, violation := board.CheckAndPlay(&castling)

	assert.False(t, valid)
	assert.Equal(t, CastlingWhileKingInCheck, violation)
}

func Test_Board_WhiteCastlesLeft_QueenCoversKingsSquare(t *testing.T) {
	board := newBoard()

	board.position[types.Coordinate{Col: 5, Row: 1}] = King{Color: types.White}
	board.position[types.Coordinate{Col: 1, Row: 1}] = Rook{Color: types.White}
	board.position[types.Coordinate{Col: 3, Row: 5}] = Queen{Color: types.Black}

	castling := types.Move{
		StartSquare: types.Coordinate{Col: 5, Row: 1},
		EndSquare:   types.Coordinate{Col: 3, Row: 1},
		ColorMoved:  types.White,
	}

	valid, _ := board.CheckAndPlay(&castling)

	assert.False(t, valid)
}

func Test_Board_BlackCastlesLeft_QueenCoversSquareInBetween(t *testing.T) {
	board := newBoard()
	board.colorToMove = types.Black

	board.position[types.Coordinate{Col: 5, Row: 8}] = King{Color: types.Black}
	board.position[types.Coordinate{Col: 1, Row: 8}] = Rook{Color: types.Black}
	board.position[types.Coordinate{Col: 4, Row: 4}] = Queen{Color: types.White}

	castling := types.Move{
		StartSquare: types.Coordinate{Col: 5, Row: 8},
		EndSquare:   types.Coordinate{Col: 3, Row: 8},
		ColorMoved:  types.Black,
	}

	valid, _ := board.CheckAndPlay(&castling)

	assert.False(t, valid)
}

func Test_Board_BlackCastlesRight_QueenCoversSquareInBetween(t *testing.T) {
	board := newBoard()
	board.colorToMove = types.Black

	board.position[types.Coordinate{Col: 5, Row: 8}] = King{Color: types.Black}
	board.position[types.Coordinate{Col: 8, Row: 8}] = Rook{Color: types.Black}
	board.position[types.Coordinate{Col: 6, Row: 4}] = Queen{Color: types.White}

	castling := types.Move{
		StartSquare: types.Coordinate{Col: 5, Row: 8},
		EndSquare:   types.Coordinate{Col: 7, Row: 8},
		ColorMoved:  types.Black,
	}

	valid, _ := board.CheckAndPlay(&castling)

	assert.False(t, valid)
}

func Test_Board_BlackCastlesLeft_KingInCheck(t *testing.T) {
	board := newBoard()
	board.colorToMove = types.Black

	board.position[types.Coordinate{Col: 5, Row: 8}] = King{Color: types.Black}
	board.position[types.Coordinate{Col: 1, Row: 8}] = Rook{Color: types.Black}
	board.position[types.Coordinate{Col: 5, Row: 4}] = Queen{Color: types.White}

	castling := types.Move{
		StartSquare: types.Coordinate{Col: 5, Row: 8},
		EndSquare:   types.Coordinate{Col: 3, Row: 8},
		ColorMoved:  types.Black,
	}

	valid, violation := board.CheckAndPlay(&castling)

	assert.False(t, valid)
	assert.Equal(t, CastlingWhileKingInCheck, violation)
}

func Test_Board_BlackCastlesLeft_QueenCoversKingsSquare(t *testing.T) {
	board := newBoard()
	board.colorToMove = types.Black

	board.position[types.Coordinate{Col: 5, Row: 8}] = King{Color: types.Black}
	board.position[types.Coordinate{Col: 1, Row: 8}] = Rook{Color: types.Black}
	board.position[types.Coordinate{Col: 3, Row: 4}] = Queen{Color: types.White}

	castling := types.Move{
		StartSquare: types.Coordinate{Col: 5, Row: 8},
		EndSquare:   types.Coordinate{Col: 3, Row: 8},
		ColorMoved:  types.Black,
	}

	valid, _ := board.CheckAndPlay(&castling)

	assert.False(t, valid)
}

func Test_Board_WhiteCastlesLeft_NoRook(t *testing.T) {
	board := newBoard()

	board.position[types.Coordinate{Col: 5, Row: 1}] = King{Color: types.White}

	castling := types.Move{
		StartSquare: types.Coordinate{Col: 5, Row: 1},
		EndSquare:   types.Coordinate{Col: 3, Row: 1},
		ColorMoved:  types.White,
	}

	valid, _ := board.CheckAndPlay(&castling)

	assert.False(t, valid)
}

func Test_Board_WhiteCastlesRight_NoRook(t *testing.T) {
	board := newBoard()

	board.position[types.Coordinate{Col: 5, Row: 1}] = King{Color: types.White}

	castling := types.Move{
		StartSquare: types.Coordinate{Col: 5, Row: 1},
		EndSquare:   types.Coordinate{Col: 7, Row: 1},
		ColorMoved:  types.White,
	}

	valid, _ := board.CheckAndPlay(&castling)

	assert.False(t, valid)
}

func Test_Board_BlackCastlesLeft_NoRook(t *testing.T) {
	board := newBoard()
	board.colorToMove = types.Black

	kingSquare := types.Coordinate{Col: 5, Row: 8}
	kingDestinationSquare := types.Coordinate{Col: 3, Row: 8}

	board.position[kingSquare] = King{Color: types.Black}

	castling := types.Move{
		StartSquare: kingSquare,
		EndSquare:   kingDestinationSquare,
		ColorMoved:  types.Black,
	}

	valid, _ := board.CheckAndPlay(&castling)

	assert.False(t, valid)
	assert.Equal(t, nil, board.getPieceAt(kingDestinationSquare))
}

func Test_Board_BlackCastlesRight_NoRook(t *testing.T) {
	board := newBoard()
	board.colorToMove = types.Black

	board.position[types.Coordinate{Col: 5, Row: 8}] = King{Color: types.Black}

	castling := types.Move{
		StartSquare: types.Coordinate{Col: 5, Row: 8},
		EndSquare:   types.Coordinate{Col: 7, Row: 8},
		ColorMoved:  types.Black,
	}

	valid, _ := board.CheckAndPlay(&castling)

	assert.False(t, valid)
}

func Test_Board_fixBugThatPreventsCastling(t *testing.T) {
	board := newBoard()
	board.Init()

	//white move
	valid, violation := board.CheckAndPlay(&types.Move{StartSquare: types.Coordinate{Col: 5, Row: 2}, EndSquare: types.Coordinate{Col: 5, Row: 3}})
	assert.True(t, valid)
	assert.Empty(t, violation)
	//black move
	valid, violation = board.CheckAndPlay(&types.Move{StartSquare: types.Coordinate{Col: 5, Row: 7}, EndSquare: types.Coordinate{Col: 5, Row: 6}})
	assert.True(t, valid)
	assert.Empty(t, violation)
	//white move
	valid, violation = board.CheckAndPlay(&types.Move{StartSquare: types.Coordinate{Col: 4, Row: 2}, EndSquare: types.Coordinate{Col: 4, Row: 3}})
	assert.True(t, valid)
	assert.Empty(t, violation)
	//black move
	valid, violation = board.CheckAndPlay(&types.Move{StartSquare: types.Coordinate{Col: 6, Row: 7}, EndSquare: types.Coordinate{Col: 6, Row: 6}})
	assert.True(t, valid)
	assert.Empty(t, violation)
	//queen moves to check the king
	valid, violation = board.CheckAndPlay(&types.Move{StartSquare: types.Coordinate{Col: 4, Row: 1}, EndSquare: types.Coordinate{Col: 8, Row: 5}})
	assert.True(t, valid)
	assert.Empty(t, violation)

	//this moves should be valid but it was not because of a bug
	valid, violation = board.CheckAndPlay(&types.Move{StartSquare: types.Coordinate{Col: 5, Row: 8}, EndSquare: types.Coordinate{Col: 5, Row: 7}})
	assert.True(t, valid)
	assert.Empty(t, violation)
}