Fix 2021/day04 flaky tests (#65)

* fix: 2021/day04 deadlock and race issues

* chore: Update test run scripts

* tests: Update regression tests

* refactor: Add board id

* fix: 2021/day04 flaky bug

Author: obalunenko

internal/puzzles/solutions/2021/day04/solution.go

@@ -8,6 +8,7 @@ import (
 	"io"
 	"regexp"
 	"strconv"
+	"sync"
 
 	"github.com/obalunenko/advent-of-code/internal/puzzles"
 )
@@ -105,10 +106,6 @@ func (b *bingo) start(ctx context.Context, rule winRule) (wonBoard *board, lastN
 			for i := range players {
 				p := players[i]
 
-				if !p.isActive() {
-					continue
-				}
-
 				p.input() <- n
 			}
 		}
@@ -142,17 +139,22 @@ func checkWinner(cancelFunc context.CancelFunc, in, out chan winner, rule winRul
 }
 
 type player struct {
+	mu     *sync.Mutex
 	id     int
 	in     chan int
-	win    chan winSig
+	win    chan winner
 	active bool
 	b      *board
 }
 
-func (p player) isActive() bool {
+func (p *player) isActive() bool {
 	return p.active
 }
 
+func (p *player) setInactive() {
+	p.active = false
+}
+
 func (p *player) input() chan int {
 	return p.in
 }
@@ -161,25 +163,36 @@ func (p *player) play(ctx context.Context) {
 	for {
 		select {
 		case <-ctx.Done():
-			p.active = false
+			p.mu.Lock()
 
-			return
+			p.setInactive()
+
+			p.mu.Unlock()
 		case num := <-p.in:
+			p.mu.Lock()
+			if !p.isActive() {
+				p.mu.Unlock()
+
+				continue
+			}
+
 			pos, ok := p.b.isPresent(num)
 			if ok {
 				p.b.state.update(ctx, pos)
+
 				p.b.numbers[pos.vertical][pos.horizontal].setMarked()
 			}
 
 			if p.b.state.isWon() {
-				p.win <- winSig{
+				p.win <- winner{
+					id:  p.id,
 					num: num,
 				}
 
-				p.active = false
-
-				return
+				p.setInactive()
 			}
+
+			p.mu.Unlock()
 		}
 	}
 }
@@ -189,28 +202,16 @@ type winner struct {
 	num int
 }
 
-type winSig struct {
-	num int
-}
-
 func newPlayer(ctx context.Context, id int, wonSig chan winner, b *board) *player {
 	p := player{
+		mu:     &sync.Mutex{},
 		id:     id,
 		in:     make(chan int),
-		win:    make(chan winSig),
+		win:    wonSig,
 		active: true,
 		b:      b,
 	}
 
-	go func() {
-		sig := <-p.win
-
-		wonSig <- winner{
-			id:  p.id,
-			num: sig.num,
-		}
-	}()
-
 	go p.play(ctx)
 
 	return &p
@@ -230,6 +231,7 @@ func (n *number) setMarked() {
 }
 
 type board struct {
+	id      int
 	numbers [boardSize][boardSize]number
 	state   state
 }
@@ -258,8 +260,15 @@ func (p position) String() string {
 }
 
 type state struct {
-	verticals   map[int]int
-	horizontals map[int]int
+	verticals   [boardSize]int
+	horizontals [boardSize]int
+}
+
+func newState() state {
+	return state{
+		verticals:   [boardSize]int{},
+		horizontals: [boardSize]int{},
+	}
 }
 
 func (s *state) String() string {
@@ -271,7 +280,7 @@ func (s *state) update(_ context.Context, p position) {
 	s.horizontals[p.vertical]++
 }
 
-func (s state) isWon() bool {
+func (s *state) isWon() bool {
 	for i := 0; i < boardSize; i++ {
 		if s.verticals[i] == boardSize || s.horizontals[i] == boardSize {
 			return true
@@ -339,7 +348,7 @@ func newBingoGame(input io.Reader) (*bingo, error) {
 		case emptyLine:
 			boardsNum++
 
-			bg.boards = append(bg.boards, newBoard())
+			bg.boards = append(bg.boards, newBoard(boardsNum))
 
 			cursor = 0
 		case boardLine:
@@ -363,13 +372,11 @@ func newBingoGame(input io.Reader) (*bingo, error) {
 	return &bg, nil
 }
 
-func newBoard() *board {
+func newBoard(id int) *board {
 	return &board{
-		numbers: [5][5]number{},
-		state: state{
-			verticals:   make(map[int]int),
-			horizontals: make(map[int]int),
-		},
+		id:      id,
+		numbers: [boardSize][boardSize]number{},
+		state:   newState(),
 	}
 }
 

internal/puzzles/solutions/2021/day04/solution_test.go

@@ -121,42 +121,45 @@ func Test_newBingoGame(t *testing.T) {
 				input: []int{7, 4, 9, 5, 11, 17, 23, 2, 0, 14, 21, 24, 10, 16, 13, 6, 15, 25, 12, 22, 18, 20, 8, 19, 3, 26, 1},
 				boards: []*board{
 					{
-						numbers: [5][5]number{
+						id: 1,
+						numbers: [boardSize][boardSize]number{
 							{number{val: 22}, number{val: 13}, number{val: 17}, number{val: 11}, number{val: 0}},
 							{number{val: 8}, number{val: 2}, number{val: 23}, number{val: 4}, number{val: 24}},
 							{number{val: 21}, number{val: 9}, number{val: 14}, number{val: 16}, number{val: 7}},
 							{number{val: 6}, number{val: 10}, number{val: 3}, number{val: 18}, number{val: 5}},
 							{number{val: 1}, number{val: 12}, number{val: 20}, number{val: 15}, number{val: 19}},
 						},
 						state: state{
-							verticals:   map[int]int{},
-							horizontals: map[int]int{},
+							verticals:   [boardSize]int{},
+							horizontals: [boardSize]int{},
 						},
 					},
 					{
-						numbers: [5][5]number{
+						id: 2,
+						numbers: [boardSize][boardSize]number{
 							{number{val: 3}, number{val: 15}, number{val: 0}, number{val: 2}, number{val: 22}},
 							{number{val: 9}, number{val: 18}, number{val: 13}, number{val: 17}, number{val: 5}},
 							{number{val: 19}, number{val: 8}, number{val: 7}, number{val: 25}, number{val: 23}},
 							{number{val: 20}, number{val: 11}, number{val: 10}, number{val: 24}, number{val: 4}},
 							{number{val: 14}, number{val: 21}, number{val: 16}, number{val: 12}, number{val: 6}},
 						},
 						state: state{
-							verticals:   map[int]int{},
-							horizontals: map[int]int{},
+							verticals:   [boardSize]int{},
+							horizontals: [boardSize]int{},
 						},
 					},
 					{
-						numbers: [5][5]number{
+						id: 3,
+						numbers: [boardSize][boardSize]number{
 							{number{val: 14}, number{val: 21}, number{val: 17}, number{val: 24}, number{val: 4}},
 							{number{val: 10}, number{val: 16}, number{val: 15}, number{val: 9}, number{val: 19}},
 							{number{val: 18}, number{val: 8}, number{val: 23}, number{val: 26}, number{val: 20}},
 							{number{val: 22}, number{val: 11}, number{val: 13}, number{val: 6}, number{val: 5}},
 							{number{val: 2}, number{val: 0}, number{val: 12}, number{val: 3}, number{val: 7}},
 						},
 						state: state{
-							verticals:   map[int]int{},
-							horizontals: map[int]int{},
+							verticals:   [boardSize]int{},
+							horizontals: [boardSize]int{},
 						},
 					},
 				},
@@ -185,6 +188,7 @@ func Test_bingo_start(t *testing.T) {
 
 	type args struct {
 		ctx context.Context
+		wr  winRule
 	}
 
 	type expected struct {
@@ -201,9 +205,11 @@ func Test_bingo_start(t *testing.T) {
 			name: "",
 			args: args{
 				ctx: ctx,
+				wr:  rule(1),
 			},
 			expected: expected{
 				board: &board{
+					id: 3,
 					numbers: [5][5]number{
 						{
 							number{val: 14, isMarked: true},
@@ -242,14 +248,14 @@ func Test_bingo_start(t *testing.T) {
 						},
 					},
 					state: state{
-						verticals: map[int]int{
+						verticals: [boardSize]int{
 							0: 2,
 							1: 3,
 							2: 2,
 							3: 2,
 							4: 3,
 						},
-						horizontals: map[int]int{
+						horizontals: [boardSize]int{
 							0: 5,
 							1: 1,
 							2: 1,
@@ -267,7 +273,7 @@ func Test_bingo_start(t *testing.T) {
 		t.Run(tt.name, func(t *testing.T) {
 			b := bgame
 
-			gotBoard, gotNum := b.start(tt.args.ctx, rule(1))
+			gotBoard, gotNum := b.start(tt.args.ctx, tt.args.wr)
 
 			equalBoards(t, tt.expected.board, gotBoard)
 			assert.Equal(t, tt.expected.num, gotNum)
@@ -278,13 +284,16 @@ func Test_bingo_start(t *testing.T) {
 func equalBoards(t testing.TB, expected, got *board) {
 	assert.Equal(t, expected.numbers, got.numbers, "numbers")
 
+	assert.Equal(t, expected.id, got.id, "id")
+
 	assert.Equal(t, fmt.Sprint(expected.state.horizontals), fmt.Sprint(got.state.horizontals), "horizontals")
 
 	assert.Equal(t, fmt.Sprint(expected.state.verticals), fmt.Sprint(got.state.verticals), "verticals")
 }
 
 func Test_board_sumMarked(t *testing.T) {
 	b := board{
+		id: 0,
 		numbers: [5][5]number{
 			{
 				number{val: 14, isMarked: true},
@@ -323,14 +332,14 @@ func Test_board_sumMarked(t *testing.T) {
 			},
 		},
 		state: state{
-			verticals: map[int]int{
+			verticals: [boardSize]int{
 				0: 2,
 				1: 3,
 				2: 2,
 				3: 2,
 				4: 3,
 			},
-			horizontals: map[int]int{
+			horizontals: [boardSize]int{
 				0: 5,
 				1: 1,
 				2: 1,

scripts/tests/run-regression.sh

@@ -10,12 +10,12 @@ export AOC_REGRESSION_ENABLED=true
 
 REGRESSION_TESTS_PKG=$(go list -m)/tests
 
-GOTEST="go test -v -race"
-if [ -f "$(go env GOPATH)/bin/gotestsum" ] || [ -f "/usr/local/bin/gotestsum" ]; then
+GOTEST="go test "
+if command -v "gotestsum" &>/dev/null; then
   GOTEST="gotestsum --format pkgname --"
 fi
 
-${GOTEST} "${REGRESSION_TESTS_PKG}"
+${GOTEST} -race "${REGRESSION_TESTS_PKG}"
 
 unset AOC_REGRESSION_ENABLED
 

scripts/tests/run.sh

@@ -1,16 +1,16 @@
-#!/bin/sh
+#!/bin/bash
 
 set -eu pipefail
 
 SCRIPT_NAME="$(basename "$0")"
 
 echo "${SCRIPT_NAME} is running... "
 
-GOTEST="go test -v -race"
-if [ -f "$(go env GOPATH)/bin/gotestsum" ] || [ -f "/usr/local/bin/gotestsum" ]; then
+GOTEST="go test -v "
+if command -v "gotestsum" &>/dev/null; then
   GOTEST="gotestsum --format pkgname --"
 fi
 
-${GOTEST} ./...
+${GOTEST} -race ./...
 
 echo "${SCRIPT_NAME} done."

tests/regression_test.go

@@ -2303,7 +2303,7 @@ func testcases2021() []testcase {
 				Year:  year,
 				Name:  puzzles.Day04.String(),
 				Part1: "58374",
-				Part2: "",
+				Part2: "11377",
 			},
 			wantErr: false,
 		},