latest

multiplier in scoring needs to increase by *100 for each item within
the hand type, because ranks are 2-14

.gitignore

@@ -5,9 +5,45 @@
 *.so
 *.dylib
 
-# Test binary, build with `go test -c`
-*.test
-
 # Output of the go coverage tool, specifically when used with LiteIDE
 *.out
+
+# Go workspace file
+go.work
+go.work.sum
+
+# Dependency directories
+vendor/
+
+# Go build artifacts
+bin/
+build/
+dist/
+
+# Configuration files for editors and tools
+.vscode/
+.idea/
+*.swp
+*.swo
+
+# Logs
+*.log
+
+# Temporary files
+*.tmp
+*.temp
+*.bak
+
+# Test binary, coverage, and results
+*.test
+*.cover
+*.cov
+*.profile
+*.prof
+
+# OS-specific files
 .DS_Store
+Thumbs.db
+
+# i don't know what keeps creating this file
+examples/simgame/simgame

Makefile

@@ -1,4 +1,24 @@
-default: test
+.PHONY: examples
+
+default: run
+
+run: simgame
+
+simgame: examples
+	RANDOM_SHUFFLE=1 ./bin/simgame
+
+clean:
+	rm -rf bin *.test
 
 test:
-	go test -v ./...
+	go test -count=1 .
+
+examples:
+	test -d bin || mkdir bin
+	go build -o bin/ ./examples/...
+
+lint:
+	golangci-lint run
+
+fmt:
+	go fmt ./...

card.go

@@ -5,8 +5,9 @@ import (
 	"slices"
 	"sort"
 	"strings"
+	"unicode/utf8"
 
-	"github.com/logrusorgru/aurora/v4"
+	aurora "github.com/logrusorgru/aurora/v4"
 )
 
 type Card struct {
@@ -14,62 +15,56 @@ type Card struct {
 	Suit Suit
 }
 
-func NewRankFromString(rank string) Rank {
-	switch rank {
-	case "2":
-		return Rank(DEUCE)
-	case "3":
-		return Rank(THREE)
-	case "4":
-		return Rank(FOUR)
-	case "5":
-		return Rank(FIVE)
-	case "6":
-		return Rank(SIX)
-	case "7":
-		return Rank(SEVEN)
-	case "8":
-		return Rank(EIGHT)
-	case "9":
-		return Rank(NINE)
-	case "T":
-		return Rank(TEN)
-	case "J":
-		return Rank(JACK)
-	case "Q":
-		return Rank(QUEEN)
-	case "K":
-		return Rank(KING)
-	case "A":
-		return Rank(ACE)
-	}
-	return Rank(0)
-}
-
-func NewSuitFromString(suit string) Suit {
-	switch suit {
-	case string(SPADE):
-		return Suit(SPADE)
-	case string(CLUB):
-		return Suit(CLUB)
-	case string(HEART):
-		return Suit(HEART)
-	case string(DIAMOND):
-		return Suit(DIAMOND)
-	}
-	return Suit(0)
-}
-
 func NewCardFromString(card string) (Card, error) {
 	// FIXME extend this later to common format strings like "9s"
-	if len(card) != 2 {
-		return Card{}, fmt.Errorf("Invalid card string %s", card)
+	length := utf8.RuneCountInString(card)
+	if length != 2 {
+		return Card{}, fmt.Errorf("invalid card string %s, must be 2 characters", card)
 	}
-	rank := NewRankFromString(card[0:1])
-	suit := NewSuitFromString(card[1:2])
+
+	rankMap := map[rune]Rank{
+		rune(DEUCE): DEUCE,
+		rune(THREE): THREE,
+		rune(FOUR):  FOUR,
+		rune(FIVE):  FIVE,
+		rune(SIX):   SIX,
+		rune(SEVEN): SEVEN,
+		rune(EIGHT): EIGHT,
+		rune(NINE):  NINE,
+		rune(TEN):   TEN,
+		rune(JACK):  JACK,
+		rune(QUEEN): QUEEN,
+		rune(KING):  KING,
+		rune(ACE):   ACE,
+	}
+
+	suitMap := map[rune]Suit{
+		rune(SPADE):   SPADE,
+		rune(HEART):   HEART,
+		rune(DIAMOND): DIAMOND,
+		rune(CLUB):    CLUB,
+	}
+
+	var rank Rank
+	var suit Suit
+	for r := range rankMap {
+		if strings.ContainsRune(card, r) {
+			rank = rankMap[r]
+			break
+		}
+	}
+
+	for s := range suitMap {
+		if strings.ContainsRune(card, s) {
+			suit = suitMap[s]
+			break
+		}
+	}
+
 	if rank == Rank(0) || suit == Suit(0) {
-		return Card{}, fmt.Errorf("Invalid card string %s", card)
+		return Card{}, fmt.Errorf("invalid card string %s", card)
 	}
+
 	return Card{Rank: rank, Suit: suit}, nil
 }
 
@@ -77,17 +72,17 @@ func NewCardsFromString(cards string) (Cards, error) {
 	// supports a string like 9♠,9♣,Q♥,Q♦,K♣
 	// FIXME extend this later to common format strings like "9c Qh Qd Kc"
 	// with or without commas
-	var newCards Cards
 	cardStrings := strings.Split(cards, ",")
-	for _, cardString := range cardStrings {
+	newCards := make(Cards, len(cardStrings))
+	for i, cardString := range cardStrings {
 		card, err := NewCardFromString(cardString)
 		if err != nil {
-			return Cards{}, err
+			return nil, err
 		}
-		newCards = append(newCards, card)
+		newCards[i] = card
 	}
 	if len(newCards) == 0 {
-		return Cards{}, fmt.Errorf("No cards found in string %s", cards)
+		return nil, fmt.Errorf("no cards found in string %s", cards)
 	}
 	return newCards, nil
 }
@@ -98,42 +93,41 @@ func (c *Card) String() string {
 
 type Cards []Card
 
-func (c Cards) First() Card {
-	return c[0]
+func (cards Cards) First() Card {
+	return cards[0]
 }
 
-func (c Cards) Second() Card {
-	return c[1]
+func (cards Cards) Second() Card {
+	return cards[1]
 }
 
-func (c Cards) Third() Card {
-	return c[2]
+func (cards Cards) Third() Card {
+	return cards[2]
 }
 
-func (c Cards) Fourth() Card {
-	return c[3]
+func (cards Cards) Fourth() Card {
+	return cards[3]
 }
 
-func (c Cards) Fifth() Card {
-	return c[4]
+func (cards Cards) Fifth() Card {
+	return cards[4]
 }
 
-func (c Cards) Last() Card {
-	return c[len(c)-1]
+func (cards Cards) Last() Card {
+	return cards[len(cards)-1]
 }
 
-func (c Cards) SortByRankAscending() Cards {
-	newCards := make(Cards, len(c))
-	copy(newCards, c)
-	sort.Slice(newCards, func(i, j int) bool {
-		return newCards[i].Rank.Score() < newCards[j].Rank.Score()
+func (cards Cards) SortByRankAscending() Cards {
+	sortedCards := make(Cards, len(cards))
+	copy(sortedCards, cards)
+	sort.Slice(sortedCards, func(i, j int) bool {
+		return sortedCards[i].Rank.Score() < sortedCards[j].Rank.Score()
 	})
-
-	return newCards
+	return sortedCards
 }
 
-func (c Cards) PrintToTerminal() {
-	fmt.Printf("%s", c.FormatForTerminal())
+func (cards Cards) PrintToTerminal() {
+	fmt.Printf("%s", cards.FormatForTerminal())
 }
 
 type SortOrder int
@@ -143,18 +137,18 @@ const (
 	AceHighDescending
 )
 
-func (c Cards) FormatForTerminalSorted(order SortOrder) string {
-	sorted := c.SortByRankAscending() // this is ascending
+func (cards Cards) FormatForTerminalSorted(order SortOrder) string {
+	sorted := cards.SortByRankAscending() // this is ascending
 	if order == AceHighDescending {
 		slices.Reverse(sorted)
 	}
 	return sorted.FormatForTerminal()
 }
 
-func (c Cards) FormatForTerminal() string {
+func (cards Cards) FormatForTerminal() string {
 	var cardstrings []string
-	for i := 0; i < len(c); i++ {
-		cardstrings = append(cardstrings, c[i].FormatForTerminal())
+	for i := 0; i < len(cards); i++ {
+		cardstrings = append(cardstrings, cards[i].FormatForTerminal())
 	}
 	return strings.Join(cardstrings, ",")
 }
@@ -179,16 +173,15 @@ func (c Card) FormatForTerminal() string {
 	return fmt.Sprintf("%s%s", rank, suit)
 }
 
-func (c Cards) HighestRank() Rank {
-	sorted := c.SortByRankAscending()
+func (cards Cards) HighestRank() Rank {
+	sorted := cards.SortByRankAscending()
 	return sorted[len(sorted)-1].Rank
 }
 
-func (s Cards) String() (output string) {
+func (cards Cards) String() string {
 	var cardstrings []string
-	for i := 0; i < len(s); i++ {
-		cardstrings = append(cardstrings, s[i].String())
+	for i := 0; i < len(cards); i++ {
+		cardstrings = append(cardstrings, cards[i].String())
 	}
-	output = strings.Join(cardstrings, ",")
-	return output
+	return strings.Join(cardstrings, ",")
 }

examples/flip/main.go

@@ -0,0 +1,119 @@
+package main
+
+import (
+	"fmt"
+
+	"git.eeqj.de/sneak/pokercore"
+)
+
+var playerCount = 2
+
+type Player struct {
+	Hand       pokercore.Cards
+	ScoredHand *pokercore.PokerHand
+	Position   int
+}
+
+type Game struct {
+	Deck      *pokercore.Deck
+	Players   []*Player
+	Community pokercore.Cards
+	Street    int
+}
+
+func NewGame() *Game {
+	g := &Game{}
+	g.Street = 0
+	g.Deck = pokercore.NewDeck()
+	g.Deck.ShuffleRandomly()
+	return g
+}
+
+func (g *Game) StreetAsString() string {
+	switch g.Street {
+	case 0:
+		return "pre-flop"
+	case 1:
+		return "flop"
+	case 2:
+		return "turn"
+	case 3:
+		return "river"
+	}
+	return "unknown"
+}
+
+func (g *Game) DealPlayersIn() {
+	for i := 0; i < playerCount; i++ {
+		p := Player{Hand: g.Deck.Deal(2), Position: i + 1}
+		g.Players = append(g.Players, &p)
+	}
+}
+
+func (g *Game) ShowGameStatus() {
+	fmt.Printf("Street: %s\n", g.StreetAsString())
+	fmt.Printf("Community cards: %s\n", g.Community.FormatForTerminal())
+	for _, p := range g.Players {
+		if p != nil {
+			fmt.Printf("Player %d: %s\n", p.Position, p.Hand.FormatForTerminal())
+			if g.Street > 0 {
+				ac := append(p.Hand, g.Community...)
+				ph, err := ac.PokerHand()
+				if err != nil {
+					panic(err)
+				}
+				fmt.Printf("Player %d has %s\n", p.Position, ph.Description())
+				fmt.Printf("Player %d Score: %d\n", p.Position, ph.Score)
+			}
+		}
+	}
+}
+
+func (g *Game) DealFlop() {
+	g.Community = g.Deck.Deal(3)
+	g.Street = 1
+}
+
+func (g *Game) DealTurn() {
+	g.Community = append(g.Community, g.Deck.Deal(1)...)
+	g.Street = 2
+}
+
+func (g *Game) DealRiver() {
+	g.Community = append(g.Community, g.Deck.Deal(1)...)
+	g.Street = 3
+}
+
+func (g *Game) ShowWinner() {
+	var winner *Player
+	var winningHand *pokercore.PokerHand
+	for _, p := range g.Players {
+		if p != nil {
+			ac := append(p.Hand, g.Community...)
+			ph, err := ac.PokerHand()
+			if err != nil {
+				panic(err)
+			}
+			if winner == nil {
+				winner = p
+				winningHand = ph
+			} else {
+				if ph.Score > winningHand.Score {
+					winner = p
+					winningHand = ph
+				}
+			}
+		}
+	}
+	fmt.Printf("Winner: Player %d with %s.\n", winner.Position, winningHand.Description())
+}
+
+func main() {
+	g := NewGame()
+	g.DealPlayersIn()
+	g.DealFlop()
+	g.DealTurn()
+	g.DealRiver()
+	g.ShowGameStatus()
+	g.ShowWinner()
+}

examples/montecarlo/main.go

@@ -0,0 +1,155 @@
+package main
+
+import (
+	"fmt"
+	"time"
+
+	"github.com/rcrowley/go-metrics"
+	"github.com/schollz/progressbar/v3"
+	"sneak.berlin/go/pokercore"
+)
+
+var gameCount = 50_000
+var playerCount = 2
+
+type Player struct {
+	Hand       pokercore.Cards
+	ScoredHand *pokercore.PokerHand
+	Position   int
+}
+
+type Game struct {
+	Deck      *pokercore.Deck
+	Players   []*Player
+	Community pokercore.Cards
+	Street    int
+}
+
+func NewGame() *Game {
+	g := &Game{}
+	g.Street = 0
+	g.Deck = pokercore.NewDeck()
+	g.Deck.ShuffleRandomly()
+	return g
+}
+
+func (g *Game) StreetAsString() string {
+	switch g.Street {
+	case 0:
+		return "pre-flop"
+	case 1:
+		return "flop"
+	case 2:
+		return "turn"
+	case 3:
+		return "river"
+	}
+	return "unknown"
+}
+
+func (g *Game) DealPlayersIn() {
+	for i := 0; i < playerCount; i++ {
+		p := Player{Hand: g.Deck.Deal(2), Position: i + 1}
+		g.Players = append(g.Players, &p)
+	}
+}
+
+func (g *Game) DealFlop() {
+	g.Community = g.Deck.Deal(3)
+	g.Street = 1
+}
+
+func (g *Game) DealTurn() {
+	g.Community = append(g.Community, g.Deck.Deal(1)...)
+	g.Street = 2
+}
+
+func (g *Game) DealRiver() {
+	g.Community = append(g.Community, g.Deck.Deal(1)...)
+	g.Street = 3
+}
+
+func (g *Game) ShowWinner() int {
+	var winner *Player
+	var winningHand *pokercore.PokerHand
+	for _, p := range g.Players {
+		if p != nil {
+			ac := append(p.Hand, g.Community...)
+			ph, err := ac.PokerHand()
+			if err != nil {
+				panic(err)
+			}
+			if winner == nil {
+				winner = p
+				winningHand = ph
+			} else {
+				if ph.Score > winningHand.Score {
+					winner = p
+					winningHand = ph
+				}
+			}
+		}
+	}
+	return winner.Position
+}
+
+func main() {
+	oneWins := 0
+	twoWins := 0
+
+	registry := metrics.NewRegistry()
+	timer := metrics.NewTimer()
+	registry.Register("pokerGame", timer)
+
+	bar := progressbar.NewOptions(
+		gameCount,
+		progressbar.OptionSetDescription("Gambling..."),
+		progressbar.OptionShowCount(),
+		progressbar.OptionShowIts(),
+		progressbar.OptionSetPredictTime(true),
+		progressbar.OptionClearOnFinish(),
+		progressbar.OptionThrottle(
+			100*time.Millisecond,
+		), // Update every 100ms
+	)
+
+	for i := 0; i < gameCount; i++ {
+		start := time.Now()
+		w := runFlip()
+		duration := time.Since(start)
+		timer.Update(duration)
+		bar.Add(1)
+		if w == 1 {
+			oneWins++
+		} else {
+			twoWins++
+		}
+	}
+
+	fmt.Printf("%d games played\n", gameCount)
+	fmt.Printf("Min: %d ns\n", timer.Min())
+	fmt.Printf("Max: %d ns\n", timer.Max())
+	fmt.Printf("Mean: %0.2f ns\n", timer.Mean())
+	fmt.Printf("StdDev: %0.2f ns\n", timer.StdDev())
+	fmt.Printf(
+		"Percentiles: 50%%: %0.2f ns, 75%%: %0.2f ns, 95%%: %0.2f ns, 99%%: %0.2f ns\n",
+		timer.Percentile(0.50),
+		timer.Percentile(0.75),
+		timer.Percentile(0.95),
+		timer.Percentile(0.99),
+	)
+	oneWinPercentage := float64(oneWins) / float64(gameCount) * 100
+	twoWinPercentage := float64(twoWins) / float64(gameCount) * 100
+	fmt.Printf("Player 1 won: %d (%0.2f%%)\n", oneWins, oneWinPercentage)
+	fmt.Printf("Player 2 won: %d (%0.2f%%)\n", twoWins, twoWinPercentage)
+}
+
+func runFlip() int {
+	g := NewGame()
+	g.DealPlayersIn()
+	g.DealFlop()
+	g.DealTurn()
+	g.DealRiver()
+	winnerPosition := g.ShowWinner()
+	return winnerPosition
+}

examples/sf/main.go

@@ -0,0 +1,56 @@
+package main
+
+import (
+	"fmt"
+
+	"sneak.berlin/go/pokercore"
+)
+
+func main() {
+	var sfp bool
+	var tries int
+	var found int
+
+	const maxTries = 100_000_000
+
+	for i := 0; i < maxTries; i++ {
+		sfp = searchStraightFlush()
+		if sfp {
+			found++
+		}
+		tries++
+		if tries%1000 == 0 {
+			fmt.Printf("Tries: %d, Found: %d\n", tries, found)
+		}
+	}
+	fmt.Printf("Tries: %d, Found: %d\n", tries, found)
+}
+
+func searchStraightFlush() bool {
+
+	d := pokercore.NewDeck()
+
+	d.ShuffleRandomly()
+
+	var hand pokercore.Cards
+
+	hand = d.Deal(7)
+
+	ph, err := hand.PokerHand()
+
+	if err != nil {
+		fmt.Println("Error: ", err)
+		return false
+	}
+
+	if ph.Type == pokercore.StraightFlush ||
+		ph.Type == pokercore.RoyalFlush {
+		fmt.Println("straight flush found")
+		fmt.Println("Hand: ", hand.FormatForTerminal())
+		fmt.Println("PokerHand: ", ph)
+		return true
+	}
+
+	return false
+
+}

examples/simgame/main.go

@@ -0,0 +1,170 @@
+package main
+
+import (
+	"fmt"
+	"os"
+	"time"
+
+	"git.eeqj.de/sneak/pokercore"
+)
+
+// just like on tv
+var delayTime = 2 * time.Second
+var playerCount = 8
+
+type Player struct {
+	Hand       pokercore.Cards
+	ScoredHand *pokercore.PokerHand
+	Position   int
+}
+
+type Game struct {
+	Deck      *pokercore.Deck
+	Players   []*Player
+	Community pokercore.Cards
+	Street    int
+}
+
+func suspense() {
+	fmt.Printf("########################################\n")
+	if os.Getenv("NO_LAG") == "" {
+		time.Sleep(delayTime)
+	}
+}
+
+func NewGame() *Game {
+
+	// this "randomly chosen" seed somehow deals pocket queens, pocket kings, and pocket aces to three players.
+	// what are the odds? lol
+	//g := NewGame(1337))
+
+	// nothing up my sleeve:
+	seed := 3141592653
+
+	g := &Game{}
+	g.Street = 0
+
+	g.Deck = pokercore.NewDeck()
+	g.SpreadCards()
+
+	fmt.Printf("Shuffle up and deal!\n")
+	suspense()
+	fmt.Printf("Shuffling...\n")
+
+	if os.Getenv("RANDOM_SHUFFLE") != "" {
+		g.Deck.ShuffleRandomly()
+	} else {
+		fmt.Printf("Using deterministic shuffle seed: %d\n", seed)
+		g.Deck.ShuffleDeterministically(int64(seed))
+	}
+	return g
+}
+
+func (g *Game) StreetAsString() string {
+	switch g.Street {
+	case 0:
+		return "pre-flop"
+	case 1:
+		return "flop"
+	case 2:
+		return "turn"
+	case 3:
+		return "river"
+	}
+	return "unknown"
+}
+
+func (g *Game) SpreadCards() {
+	fmt.Printf("deck before shuffling: %s\n", g.Deck.FormatForTerminal())
+}
+
+func (g *Game) DealPlayersIn() {
+	for i := 0; i < playerCount; i++ {
+		p := Player{Hand: g.Deck.Deal(2), Position: i + 1}
+		g.Players = append(g.Players, &p)
+	}
+}
+
+func (g *Game) ShowGameStatus() {
+	fmt.Printf("Street: %s\n", g.StreetAsString())
+	fmt.Printf("Community cards: %s\n", g.Community.FormatForTerminal())
+	for _, p := range g.Players {
+		if p != nil {
+			fmt.Printf("Player %d: %s\n", p.Position, p.Hand.FormatForTerminal())
+			if g.Street > 0 {
+				ac := append(p.Hand, g.Community...)
+				ph, err := ac.PokerHand()
+				if err != nil {
+					panic(err)
+				}
+				fmt.Printf("Player %d has %s\n", p.Position, ph.Description())
+				fmt.Printf("Player %d Score: %d\n", p.Position, ph.Score)
+			}
+		}
+	}
+}
+
+func (g *Game) DealFlop() {
+	g.Community = g.Deck.Deal(3)
+	g.Street = 1
+}
+
+func (g *Game) DealTurn() {
+	g.Community = append(g.Community, g.Deck.Deal(1)...)
+	g.Street = 2
+}
+
+func (g *Game) DealRiver() {
+	g.Community = append(g.Community, g.Deck.Deal(1)...)
+	g.Street = 3
+}
+
+func (g *Game) ShowWinner() {
+	var winner *Player
+	var winningHand *pokercore.PokerHand
+	for _, p := range g.Players {
+		if p != nil {
+			ac := append(p.Hand, g.Community...)
+			ph, err := ac.PokerHand()
+			if err != nil {
+				panic(err)
+			}
+			if winner == nil {
+				winner = p
+				winningHand = ph
+			} else {
+				if ph.Score > winningHand.Score {
+					winner = p
+					winningHand = ph
+				}
+			}
+		}
+	}
+	fmt.Printf("Winner: Player %d with %s.\n", winner.Position, winningHand.Description())
+}
+
+func main() {
+	g := NewGame()
+
+	g.ShowGameStatus()
+	g.DealPlayersIn()
+	suspense()
+
+	g.ShowGameStatus()
+	g.DealFlop()
+	suspense()
+
+	g.ShowGameStatus()
+	g.DealTurn()
+	suspense()
+
+	g.ShowGameStatus()
+	g.DealRiver()
+	suspense()
+
+	g.ShowGameStatus()
+	g.ShowWinner()
+
+	fmt.Printf("What a strange game.  The only winning move is to bet really big.\n")
+	fmt.Printf("Insert coin to play again.\n")
+}

examples/sixhand/main.go

@@ -1,35 +0,0 @@
-package main
-
-import (
-	"fmt"
-
-	"git.eeqj.de/sneak/pokercore"
-)
-
-func main() {
-	d := pokercore.NewDeck()
-	fmt.Printf("deck before shuffling: %s\n", d.FormatForTerminal())
-	d.ShuffleDeterministically(1337 + 1) // 1337 gives too weird a result
-	fmt.Printf("deck after shuffling: %s\n", d.FormatForTerminal())
-	var players []pokercore.Cards
-	for i := 0; i < 6; i++ {
-		players = append(players, d.Deal(2))
-	}
-	for i, p := range players {
-		fmt.Printf("player %d: %s\n", i, p.FormatForTerminal())
-	}
-	// deal the flop
-	var community pokercore.Cards
-	community = d.Deal(3)
-	fmt.Printf("flop: %s\n", community.FormatForTerminal())
-	// evaluate the hands so far
-	for i, p := range players {
-		fmt.Printf("player %d: %s\n", i, p.FormatForTerminal())
-		thisPlayersHand, err := p.Append(community).PokerHand()
-		if err != nil {
-			fmt.Printf("error evaluating hand: %s\n", err)
-			continue
-		}
-		fmt.Printf("player %d: %s\n", i, thisPlayersHand.String())
-	}
-}

findhand.go

@@ -17,6 +17,14 @@ func (hand Cards) IdentifyBestFiveCardPokerHand() (Cards, error) {
 		return nil, ErrDuplicateCard
 	}
 
+	if len(hand) == 5 {
+		return hand, nil
+	}
+
+	if len(hand) < 5 {
+		return nil, errors.New("hand must have at least 5 cards to identify the best 5 card poker hand")
+	}
+
 	newHands := make([]Cards, len(hand))
 	for i := 0; i < len(hand); i++ {
 		newHand := make(Cards, len(hand)-1)

go.mod

@@ -1,17 +1,23 @@
-module git.eeqj.de/sneak/pokercore
+module sneak.berlin/go/pokercore
 
 go 1.22.2
 
 require (
-	github.com/logrusorgru/aurora v2.0.3+incompatible
+	github.com/logrusorgru/aurora/v4 v4.0.0
+	github.com/rcrowley/go-metrics v0.0.0-20201227073835-cf1acfcdf475
+	github.com/schollz/progressbar/v3 v3.14.2
 	github.com/sirupsen/logrus v1.9.3
 	github.com/stretchr/testify v1.8.0
+	sneak.berlin/go/timingbench v0.0.0-20240522212031-a6243a470213
 )
 
 require (
 	github.com/davecgh/go-spew v1.1.1 // indirect
-	github.com/logrusorgru/aurora/v4 v4.0.0 // indirect
+	github.com/mitchellh/colorstring v0.0.0-20190213212951-d06e56a500db // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
-	golang.org/x/sys v0.0.0-20220715151400-c0bba94af5f8 // indirect
+	github.com/rivo/uniseg v0.4.7 // indirect
+	golang.org/x/sys v0.20.0 // indirect
+	golang.org/x/term v0.20.0 // indirect
+	gonum.org/v1/gonum v0.15.0 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 )

go.sum

@@ -1,25 +1,45 @@
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
-github.com/logrusorgru/aurora v2.0.3+incompatible h1:tOpm7WcpBTn4fjmVfgpQq0EfczGlG91VSDkswnjF5A8=
-github.com/logrusorgru/aurora v2.0.3+incompatible/go.mod h1:7rIyQOR62GCctdiQpZ/zOJlFyk6y+94wXzv6RNZgaR4=
+github.com/k0kubun/go-ansi v0.0.0-20180517002512-3bf9e2903213/go.mod h1:vNUNkEQ1e29fT/6vq2aBdFsgNPmy8qMdSay1npru+Sw=
 github.com/logrusorgru/aurora/v4 v4.0.0 h1:sRjfPpun/63iADiSvGGjgA1cAYegEWMPCJdUpJYn9JA=
 github.com/logrusorgru/aurora/v4 v4.0.0/go.mod h1:lP0iIa2nrnT/qoFXcOZSrZQpJ1o6n2CUf/hyHi2Q4ZQ=
+github.com/mattn/go-isatty v0.0.20/go.mod h1:W+V8PltTTMOvKvAeJH7IuucS94S2C6jfK/D7dTCTo3Y=
+github.com/mitchellh/colorstring v0.0.0-20190213212951-d06e56a500db h1:62I3jR2EmQ4l5rM/4FEfDWcRD+abF5XlKShorW5LRoQ=
+github.com/mitchellh/colorstring v0.0.0-20190213212951-d06e56a500db/go.mod h1:l0dey0ia/Uv7NcFFVbCLtqEBQbrT4OCwCSKTEv6enCw=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/rcrowley/go-metrics v0.0.0-20201227073835-cf1acfcdf475 h1:N/ElC8H3+5XpJzTSTfLsJV/mx9Q9g7kxmchpfZyxgzM=
+github.com/rcrowley/go-metrics v0.0.0-20201227073835-cf1acfcdf475/go.mod h1:bCqnVzQkZxMG4s8nGwiZ5l3QUCyqpo9Y+/ZMZ9VjZe4=
+github.com/rivo/uniseg v0.4.7 h1:WUdvkW8uEhrYfLC4ZzdpI2ztxP1I582+49Oc5Mq64VQ=
+github.com/rivo/uniseg v0.4.7/go.mod h1:FN3SvrM+Zdj16jyLfmOkMNblXMcoc8DfTHruCPUcx88=
+github.com/schollz/progressbar/v3 v3.14.2 h1:EducH6uNLIWsr560zSV1KrTeUb/wZGAHqyMFIEa99ks=
+github.com/schollz/progressbar/v3 v3.14.2/go.mod h1:aQAZQnhF4JGFtRJiw/eobaXpsqpVQAftEQ+hLGXaRc4=
 github.com/sirupsen/logrus v1.9.3 h1:dueUQJ1C2q9oE3F7wvmSGAaVtTmUizReu6fjN8uqzbQ=
 github.com/sirupsen/logrus v1.9.3/go.mod h1:naHLuLoDiP4jHNo9R0sCBMtWGeIprob74mVsIT4qYEQ=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/objx v0.4.0/go.mod h1:YvHI0jy2hoMjB+UWwv71VJQ9isScKT/TqJzVSSt89Yw=
-github.com/stretchr/testify v1.7.0 h1:nwc3DEeHmmLAfoZucVR881uASk0Mfjw8xYJ99tb5CcY=
+github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
 github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 github.com/stretchr/testify v1.7.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 github.com/stretchr/testify v1.8.0 h1:pSgiaMZlXftHpm5L7V1+rVB+AZJydKsMxsQBIJw4PKk=
 github.com/stretchr/testify v1.8.0/go.mod h1:yNjHg4UonilssWZ8iaSj1OCr/vHnekPRkoO+kdMU+MU=
-golang.org/x/sys v0.0.0-20220715151400-c0bba94af5f8 h1:0A+M6Uqn+Eje4kHMK80dtF3JCXC4ykBgQG4Fe06QRhQ=
+golang.org/x/exp v0.0.0-20231110203233-9a3e6036ecaa h1:FRnLl4eNAQl8hwxVVC17teOw8kdjVDVAiFMtgUdTSRQ=
+golang.org/x/exp v0.0.0-20231110203233-9a3e6036ecaa/go.mod h1:zk2irFbV9DP96SEBUUAy67IdHUaZuSnrz1n472HUCLE=
 golang.org/x/sys v0.0.0-20220715151400-c0bba94af5f8/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.17.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+golang.org/x/sys v0.20.0 h1:Od9JTbYCk261bKm4M/mw7AklTlFYIa0bIp9BgSm1S8Y=
+golang.org/x/sys v0.20.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+golang.org/x/term v0.17.0/go.mod h1:lLRBjIVuehSbZlaOtGMbcMncT+aqLLLmKrsjNrUguwk=
+golang.org/x/term v0.20.0 h1:VnkxpohqXaOBYJtBmEppKUG6mXpi+4O6purfc2+sMhw=
+golang.org/x/term v0.20.0/go.mod h1:8UkIAJTvZgivsXaD6/pH6U9ecQzZ45awqEOzuCvwpFY=
+gonum.org/v1/gonum v0.15.0 h1:2lYxjRbTYyxkJxlhC+LvJIx3SsANPdRybu1tGj9/OrQ=
+gonum.org/v1/gonum v0.15.0/go.mod h1:xzZVBJBtS+Mz4q0Yl2LJTk+OxOg4jiXZ7qBoM0uISGo=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
-gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c h1:dUUwHk2QECo/6vqA44rthZ8ie2QXMNeKRTHCNY2nXvo=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
+sneak.berlin/go/timingbench v0.0.0-20240522212031-a6243a470213 h1:jgfwL2lUUp6aII87vgkgFenfKftsbKvUR3jlsRdS2yo=
+sneak.berlin/go/timingbench v0.0.0-20240522212031-a6243a470213/go.mod h1:W+0S+VhiuNIU/06KPhWJCmNhMaCztg2MuHitNEVEFG0=

handhelpers.go

@@ -1,38 +1,12 @@
 package pokercore
 
-func (c Cards) scoreStraightFlush() HandScore {
-	if !c.containsStraightFlush() {
-		panic("hand must be a straight flush to score it")
-	}
-	return ScoreStraightFlush + 1000*c.HighestRank().Score()
-}
-
-func (c Cards) scoreFlush() HandScore {
-	if !c.containsFlush() {
-		panic("hand must be a flush to score it")
-	}
-	var score HandScore
-	for _, card := range c {
-		score += card.Rank.Score()
-	}
-	return ScoreFlush + score
-}
-
-func (c Cards) scoreHighCard() HandScore {
-	if !c.isUnmadeHand() {
-		panic("hand must be a high card to score it")
-	}
-	var score HandScore
-	for _, card := range c {
-		score += card.Rank.Score()
-	}
-	return ScoreHighCard + score
-}
+// these helper functions are used in a Cards.PokerHand() constructor and in
+// the calculateScore() function called from it.
+// they only work with exactly five cards, no duplicates, and no wild cards.
+// they are not intended to be used in any other context, which is why
+// they are not exported
 
 func (c Cards) pairRank() Rank {
-	if !c.containsPair() {
-		panic("hand must have a pair to have a pair rank")
-	}
 	sorted := c.SortByRankAscending()
 	if sorted[0].Rank == sorted[1].Rank {
 		return sorted[0].Rank
@@ -50,9 +24,6 @@ func (c Cards) pairRank() Rank {
 }
 
 func (c Cards) pairFirstKicker() Card {
-	if !c.containsPair() {
-		panic("hand must have a pair to have a first kicker")
-	}
 	sorted := c.SortByRankAscending()
 	if sorted[0].Rank == sorted[1].Rank {
 		return sorted[4]
@@ -70,9 +41,6 @@ func (c Cards) pairFirstKicker() Card {
 }
 
 func (c Cards) pairSecondKicker() Card {
-	if !c.containsPair() {
-		panic("hand must have a pair to have a second kicker")
-	}
 	sorted := c.SortByRankAscending()
 	if sorted[0].Rank == sorted[1].Rank {
 		// first kicker is [4]
@@ -94,9 +62,6 @@ func (c Cards) pairSecondKicker() Card {
 }
 
 func (c Cards) pairThirdKicker() Card {
-	if !c.containsPair() {
-		panic("hand must have a pair to have a third kicker")
-	}
 	sorted := c.SortByRankAscending()
 	if sorted[0].Rank == sorted[1].Rank {
 		// first kicker is [4]
@@ -122,14 +87,25 @@ func (c Cards) pairThirdKicker() Card {
 }
 
 func (c Cards) twoPairBiggestPair() Rank {
-	if !c.containsTwoPair() {
-		panic("hand must have two pair to have a biggest pair")
-	}
 	sorted := c.SortByRankAscending()
 	if sorted[0].Rank == sorted[1].Rank && sorted[2].Rank == sorted[3].Rank {
 		return sorted[2].Rank
 	}
 
+	if sorted[0].Rank == sorted[1].Rank && sorted[3].Rank == sorted[4].Rank {
+		return sorted[3].Rank
+	}
+	if sorted[1].Rank == sorted[2].Rank && sorted[3].Rank == sorted[4].Rank {
+		return sorted[3].Rank
+	}
+	panic("nope")
+}
+
+func (c Cards) twoPairSmallestPair() Rank {
+	sorted := c.SortByRankAscending()
+	if sorted[0].Rank == sorted[1].Rank && sorted[2].Rank == sorted[3].Rank {
+		return sorted[0].Rank
+	}
 	if sorted[0].Rank == sorted[1].Rank && sorted[3].Rank == sorted[4].Rank {
 		return sorted[0].Rank
 	}
@@ -139,27 +115,7 @@ func (c Cards) twoPairBiggestPair() Rank {
 	panic("nope")
 }
 
-func (c Cards) twoPairSmallestPair() Rank {
-	if !c.containsTwoPair() {
-		panic("hand must have two pair to have a smallest pair")
-	}
-	sorted := c.SortByRankAscending()
-	if sorted[0].Rank == sorted[1].Rank && sorted[2].Rank == sorted[3].Rank {
-		return sorted[2].Rank
-	}
-	if sorted[0].Rank == sorted[1].Rank && sorted[3].Rank == sorted[4].Rank {
-		return sorted[3].Rank
-	}
-	if sorted[1].Rank == sorted[2].Rank && sorted[3].Rank == sorted[4].Rank {
-		return sorted[3].Rank
-	}
-	panic("nope")
-}
-
 func (c Cards) twoPairKicker() Card {
-	if !c.containsTwoPair() {
-		panic("hand must have two pair to have a twoPairKicker")
-	}
 	sorted := c.SortByRankAscending()
 	if sorted[0].Rank == sorted[1].Rank && sorted[2].Rank == sorted[3].Rank {
 		return sorted[4]
@@ -174,9 +130,6 @@ func (c Cards) twoPairKicker() Card {
 }
 
 func (c Cards) threeOfAKindTripsRank() Rank {
-	if !c.containsThreeOfAKind() {
-		panic("hand must have three of a kind to have a trips rank")
-	}
 	sorted := c.SortByRankAscending()
 	if sorted[0].Rank == sorted[1].Rank && sorted[1].Rank == sorted[2].Rank {
 		return sorted[0].Rank
@@ -191,9 +144,6 @@ func (c Cards) threeOfAKindTripsRank() Rank {
 }
 
 func (c Cards) threeOfAKindKickers() Cards {
-	if !c.containsThreeOfAKind() {
-		panic("hand must have three of a kind to have kickers")
-	}
 	sorted := c.SortByRankAscending()
 	if sorted[0].Rank == sorted[1].Rank && sorted[1].Rank == sorted[2].Rank {
 		return Cards{sorted[3], sorted[4]}
@@ -284,14 +234,7 @@ func (hand Cards) containsDuplicates() bool {
 	return false
 }
 
-func (hand Cards) IsFiveCardPokerHand() bool {
-	return len(hand) == 5 && !hand.containsDuplicates()
-}
-
 func (hand Cards) containsFlush() bool {
-	if !hand.IsFiveCardPokerHand() {
-		panic("hand must have 5 cards to be scored")
-	}
 	suit := hand[0].Suit
 	for i := 1; i < len(hand); i++ {
 		if hand[i].Suit != suit {
@@ -302,9 +245,6 @@ func (hand Cards) containsFlush() bool {
 }
 
 func (hand Cards) containsStraight() bool {
-	if !hand.IsFiveCardPokerHand() {
-		panic("hand must have 5 cards to be scored")
-	}
 	sorted := hand.SortByRankAscending()
 
 	if sorted[4].Rank == ACE && sorted[3].Rank == FIVE {
@@ -322,9 +262,8 @@ func (hand Cards) containsStraight() bool {
 }
 
 func (hand Cards) containsStraightFlush() bool {
-	if !hand.IsFiveCardPokerHand() {
-		panic("hand must have 5 cards to be scored")
-	}
+	// this of course only works on five card hands
+	// but these hand helpers are only ever called from a five card hand
 	if hand.containsStraight() && hand.containsFlush() {
 		return true
 	}
@@ -332,9 +271,6 @@ func (hand Cards) containsStraightFlush() bool {
 }
 
 func (hand Cards) containsRoyalFlush() bool {
-	if !hand.IsFiveCardPokerHand() {
-		panic("hand must have 5 cards to be scored")
-	}
 	// This seems like it works, but a five-high straight flush is not a royal flush
 	// and the highest ranked card in five-high straigh flush is an ace.
 	//if hand.containsStraightFlush() && hand.HighestRank() == ACE {
@@ -348,9 +284,6 @@ func (hand Cards) containsRoyalFlush() bool {
 }
 
 func (hand Cards) containsFourOfAKind() bool {
-	if !hand.IsFiveCardPokerHand() {
-		panic("hand must have 5 cards to be scored")
-	}
 	sorted := hand.SortByRankAscending()
 	if sorted[0].Rank == sorted[1].Rank && sorted[1].Rank == sorted[2].Rank && sorted[2].Rank == sorted[3].Rank {
 		// the quads precede the kicker
@@ -364,9 +297,6 @@ func (hand Cards) containsFourOfAKind() bool {
 }
 
 func (hand Cards) containsFullHouse() bool {
-	if !hand.IsFiveCardPokerHand() {
-		panic("hand must have 5 cards to be scored")
-	}
 	sorted := hand.SortByRankAscending()
 
 	if sorted[0].Rank == sorted[1].Rank && sorted[1].Rank == sorted[2].Rank && sorted[3].Rank == sorted[4].Rank {
@@ -381,9 +311,6 @@ func (hand Cards) containsFullHouse() bool {
 }
 
 func (hand Cards) containsPair() bool {
-	if !hand.IsFiveCardPokerHand() {
-		panic("hand must have 5 cards to be scored")
-	}
 	sorted := hand.SortByRankAscending()
 	if sorted[0].Rank == sorted[1].Rank {
 		return true
@@ -401,9 +328,6 @@ func (hand Cards) containsPair() bool {
 }
 
 func (hand Cards) containsThreeOfAKind() bool {
-	if !hand.IsFiveCardPokerHand() {
-		panic("hand must have 5 cards to be scored")
-	}
 	sorted := hand.SortByRankAscending()
 	if sorted[0].Rank == sorted[1].Rank && sorted[1].Rank == sorted[2].Rank {
 		return true
@@ -418,9 +342,6 @@ func (hand Cards) containsThreeOfAKind() bool {
 }
 
 func (hand Cards) containsTwoPair() bool {
-	if !hand.IsFiveCardPokerHand() {
-		panic("hand must have 5 cards to be scored")
-	}
 	sorted := hand.SortByRankAscending()
 	if sorted[0].Rank == sorted[1].Rank && sorted[2].Rank == sorted[3].Rank {
 		return true
@@ -435,8 +356,6 @@ func (hand Cards) containsTwoPair() bool {
 }
 
 func (hand Cards) isUnmadeHand() bool {
-	if !hand.IsFiveCardPokerHand() {
-		panic("hand must have 5 cards to be scored")
-	}
+	// i suspect this is expensive but we use it only in tests
 	return !hand.containsPair() && !hand.containsTwoPair() && !hand.containsThreeOfAKind() && !hand.containsStraight() && !hand.containsFlush() && !hand.containsFullHouse() && !hand.containsFourOfAKind() && !hand.containsStraightFlush() && !hand.containsRoyalFlush()
 }

perf_test.go

@@ -0,0 +1,83 @@
+package pokercore
+
+import (
+	"context"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+	"sneak.berlin/go/timingbench"
+)
+
+func TestShuffleSpeed(t *testing.T) {
+	t.Parallel()
+	iterations := 1000
+	t.Logf("Running %d iterations of shuffle speed test", iterations)
+	// Create a context with a timeout for cancellation.
+	ctx, cancel := context.WithTimeout(context.Background(), 20*time.Second)
+	defer cancel()
+
+	// Measure the execution times of the sample function.
+	d := NewDeck()
+	result, err := timingbench.TimeFunction(ctx, func() { d.ShuffleRandomly() }, iterations)
+	if err != nil {
+		t.Fatalf("Error measuring function: %v", err)
+	}
+	// Print the timing results.
+	t.Logf(result.String())
+}
+
+func TestHandFindingSpeedFiveCard(t *testing.T) {
+	t.Parallel()
+	iterations := 1000
+	t.Logf("Running %d iterations of hand finding speed test for 5 card hand", iterations)
+	measureHandFinding(t, iterations, 5)
+}
+
+func TestHandFindingSpeedSevenCard(t *testing.T) {
+	t.Parallel()
+	iterations := 1000
+	t.Logf("Running %d iterations of hand finding speed test for 7 card hand", iterations)
+	measureHandFinding(t, iterations, 7)
+}
+
+func TestHandFindingSpeedNineCard(t *testing.T) {
+	t.Parallel()
+	iterations := 100
+	t.Logf("Running %d iterations of hand finding speed test for 9 card hand", iterations)
+	measureHandFinding(t, iterations, 9)
+}
+
+func measureHandFinding(t *testing.T, iterations int, cardCount int) {
+	// Create a context with a timeout for cancellation.
+	ctx, cancel := context.WithTimeout(context.Background(), 20*time.Second)
+	defer cancel()
+
+	// Measure the execution times of the sample function.
+	result, err := timingbench.TimeFunction(ctx, func() {
+		findHandInRandomCards(t, int(123456789), cardCount) // check for hand in 10 cards
+	}, iterations)
+	if err != nil {
+		t.Fatalf("Error measuring function: %v", err)
+	}
+	t.Logf("Searching %d random cards for a hand takes on average %s", cardCount, result.Mean)
+	t.Logf("Over %d iterations the min was %s and the max was %s", iterations, result.Min, result.Max)
+	t.Logf("The standard deviation was %s", result.StdDev)
+	t.Logf("The median was %s", result.Median)
+
+	// Print the timing results.
+	//t.Logf(result.String())
+}
+
+func findHandInRandomCards(t *testing.T, shuffleSeed int, cardCount int) {
+	d := NewDeck()
+	d.ShuffleDeterministically(int64(shuffleSeed))
+	cards := d.Deal(cardCount)
+	hand, err := cards.IdentifyBestFiveCardPokerHand()
+	assert.Nil(t, err, "Expected no error")
+	ph, err := hand.PokerHand()
+	assert.Nil(t, err, "Expected no error")
+	//assert.Greater(t, ph.Score, 0, "Expected score to be nonzero 0")
+	desc := ph.Description()
+	assert.NotEmpty(t, desc, "Expected description to not be empty")
+}

pokercore_test.go

@@ -1,7 +1,6 @@
 package pokercore
 
 import (
-	"fmt"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -13,14 +12,15 @@ type ShuffleTestResults []struct {
 }
 
 func TestPokerDeck(t *testing.T) {
+	t.Parallel()
 	d := NewDeck()
-	fmt.Printf("newdeck: %+v\n", d)
+	//fmt.Printf("newdeck: %+v\n", d)
 	d.ShuffleDeterministically(437)
-	fmt.Printf("deterministically shuffled deck: %+v\n", d)
+	//fmt.Printf("deterministically shuffled deck: %+v\n", d)
 	cards := d.Deal(7)
 	expected := "6♥,A♦,7♥,9♣,6♠,9♥,8♣"
-	fmt.Printf("deterministically shuffled deck after dealing: %+v\n", d)
-	fmt.Printf("cards: %+v\n", cards)
+	//fmt.Printf("deterministically shuffled deck after dealing: %+v\n", d)
+	//fmt.Printf("cards: %+v\n", cards)
 	assert.Equal(t, expected, cards.String())
 
 	x := d.Count()
@@ -36,6 +36,7 @@ func TestPokerDeck(t *testing.T) {
 }
 
 func TestDealing(t *testing.T) {
+	t.Parallel()
 	d := NewDeckFromCards(Cards{
 		Card{Rank: ACE, Suit: HEART},
 		Card{Rank: DEUCE, Suit: HEART},
@@ -51,6 +52,7 @@ func TestDealing(t *testing.T) {
 }
 
 func TestSpecialCaseOfFiveHighStraightFlush(t *testing.T) {
+	t.Parallel()
 	// actual bug from first implementation
 	d := NewDeckFromCards(Cards{
 		Card{Rank: ACE, Suit: HEART},
@@ -69,6 +71,7 @@ func TestSpecialCaseOfFiveHighStraightFlush(t *testing.T) {
 }
 
 func TestSpecialCaseOfFiveHighStraight(t *testing.T) {
+	t.Parallel()
 	// actual bug from first implementation
 	d := NewDeckFromCards(Cards{
 		Card{Rank: ACE, Suit: HEART},

pokerhand.go

@@ -1,6 +1,9 @@
 package pokercore
 
-import "fmt"
+import (
+	"errors"
+	"fmt"
+)
 
 type PokerHandType int
 
@@ -28,102 +31,44 @@ func (c Cards) Append(other Cards) Cards {
 }
 
 func (c Cards) PokerHand() (*PokerHand, error) {
-	if len(c) != 5 {
-		return nil, fmt.Errorf("hand must have 5 cards to be scored as a poker hand")
-	}
 	if c.containsDuplicates() {
-		return nil, fmt.Errorf("hand must have no duplicates to be scored as a poker hand")
+		return nil, errors.New("hand must have no duplicates to be scored as a poker hand")
 	}
 
 	ph := new(PokerHand)
-	ph.Hand = c
-	if c.containsRoyalFlush() {
-		ph.Type = RoyalFlush
-		ph.Score = ScoreRoyalFlush
-		return ph, nil
+
+	// IdentifyBestFiveCardPokerHand() calls us to score hands
+	// but only if the hand is 5 cards exactly which avoids recursion loop
+	if len(c) > 5 {
+		phc, err := c.IdentifyBestFiveCardPokerHand()
+		if err != nil {
+			// this should in theory never happen
+			return nil, err
 		}
-
-	if c.containsStraightFlush() {
-		ph.Type = StraightFlush
-		ph.Score = ph.Hand.scoreStraightFlush()
-		return ph, nil
-	}
-
-	if c.containsFourOfAKind() {
-		ph.Type = FourOfAKind
-		ph.Score = ScoreFourOfAKind + 1000*c.fourOfAKindRank().Score() + c.fourOfAKindKicker().Score()
-		return ph, nil
-	}
-
-	if c.containsFullHouse() {
-		ph.Type = FullHouse
-		ph.Score = ScoreFullHouse + 1000*c.fullHouseTripsRank().Score() + c.fullHousePairRank().Score()
-		return ph, nil
-	}
-
-	if c.containsFlush() {
-		ph.Type = Flush
-		ph.Score = c.scoreFlush()
-		return ph, nil
-	}
-
-	if c.containsStraight() {
-		ph.Type = Straight
-
-		// Straights are scored by the highest card in the straight
-		// UNLESS the second highest card is a 5 and the highest card is an Ace
-		// In that case, the straight is a 5-high straight, not an Ace-high straight
-		sorted := c.SortByRankAscending()
-
-		if sorted[3].Rank == FIVE && sorted[4].Rank == ACE {
-			// 5-high straight
-			ph.Score = ScoreStraight + 1000*sorted[3].Score()
+		ph.Hand = phc.SortByRankAscending()
+	} else if len(c) == 5 {
+		ph.Hand = c.SortByRankAscending()
 	} else {
-			// All other straights
-			ph.Score = ScoreStraight + 1000*sorted[4].Score()
+		return nil, errors.New("hand must have at least 5 cards to be scored as a poker hand")
 	}
+
+	// this doesn't return an error because we've already checked for
+	// duplicates and we have already identified the best 5-card hand
+
+	// this code used to be here, but got factored out so it can go in
+	// scoring.go
+	ph.calculateScore()
+
 	return ph, nil
 }
 
-	if c.containsThreeOfAKind() {
-		ph.Type = ThreeOfAKind
-		ph.Score = ScoreThreeOfAKind
-		ph.Score += 1000 * c.threeOfAKindTripsRank().Score()
-		ph.Score += 100 * c.threeOfAKindFirstKicker().Score()
-		ph.Score += 10 * c.threeOfAKindSecondKicker().Score()
-		return ph, nil
+func (ph *PokerHand) ToSortedCards() Cards {
+	// I believe ph.Hand is already sorted, but in any case it's only 5
+	// cards and sorting it costs ~nothing
+	return ph.Hand.SortByRankAscending()
 }
 
-	if c.containsTwoPair() {
-		ph.Type = TwoPair
-		ph.Score = ScoreTwoPair
-		ph.Score += 1000 * c.twoPairBiggestPair().Score()
-		ph.Score += 100 * c.twoPairSmallestPair().Score()
-		ph.Score += 10 * c.twoPairKicker().Score()
-		return ph, nil
-	}
-
-	if c.containsPair() {
-		ph.Type = Pair
-		ph.Score = ScorePair
-		ph.Score += 1000 * c.pairRank().Score()
-		ph.Score += 100 * c.pairFirstKicker().Score()
-		ph.Score += 10 * c.pairSecondKicker().Score()
-		ph.Score += c.pairThirdKicker().Score()
-		return ph, nil
-	}
-
-	ph.Type = HighCard
-	ph.Score = c.scoreHighCard()
-	return ph, nil
-}
-
-func (ph PokerHand) ToSortedCards() Cards {
-	sorted := ph.Hand.SortByRankAscending()
-	return sorted
-}
-
-func (ph PokerHand) Compare(other PokerHand) int {
+func (ph *PokerHand) Compare(other PokerHand) int {
 	if ph.Score > other.Score {
 		return 1
 	}
@@ -133,75 +78,74 @@ func (ph PokerHand) Compare(other PokerHand) int {
 	return 0
 }
 
-func (ph PokerHand) HighestRank() Rank {
+func (ph *PokerHand) HighestRank() Rank {
 	return ph.Hand.HighestRank()
 }
 
-func (ph PokerHand) String() string {
+func (ph *PokerHand) String() string {
 	return fmt.Sprintf("<PokerHand: %s (%s)>", ph.Hand.String(), ph.Description())
 }
 
-func (c PokerHand) Description() string {
-	sortedHand := c.Hand.SortByRankAscending()
-	if c.Type == RoyalFlush {
-		return fmt.Sprintf("a royal flush in %s", c.Hand[0].Suit)
+func (ph *PokerHand) Description() string {
+	if ph.Type == RoyalFlush {
+		return fmt.Sprintf("a royal flush in %s", ph.Hand[0].Suit)
 	}
-	if c.Hand.containsStraightFlush() {
-		if sortedHand[3].Rank == FIVE && sortedHand[4].Rank == ACE {
+	if ph.Hand.containsStraightFlush() {
+		if ph.Hand[3].Rank == FIVE && ph.Hand[4].Rank == ACE {
 			// special case for steel wheel
-			return fmt.Sprintf("%s high straight flush in %s", sortedHand[3].Rank.WithArticle(), sortedHand[4].Suit)
+			return fmt.Sprintf("%s high straight flush in %s", ph.Hand[3].Rank.WithArticle(), ph.Hand[4].Suit)
 		}
-		return fmt.Sprintf("%s high straight flush in %s", c.HighestRank().WithArticle(), sortedHand[4].Suit)
+		return fmt.Sprintf("%s high straight flush in %s", ph.HighestRank().WithArticle(), ph.Hand[4].Suit)
 	}
-	if c.Hand.containsFourOfAKind() {
-		return fmt.Sprintf("four %s with %s", c.Hand.fourOfAKindRank().Pluralize(), c.Hand.fourOfAKindKicker().Rank.WithArticle())
+	if ph.Hand.containsFourOfAKind() {
+		return fmt.Sprintf("four %s with %s", ph.Hand.fourOfAKindRank().Pluralize(), ph.Hand.fourOfAKindKicker().Rank.WithArticle())
 	}
-	if c.Hand.containsFullHouse() {
-		return fmt.Sprintf("a full house, %s full of %s", c.Hand.fullHouseTripsRank().Pluralize(), c.Hand.fullHousePairRank().Pluralize())
+	if ph.Hand.containsFullHouse() {
+		return fmt.Sprintf("a full house, %s full of %s", ph.Hand.fullHouseTripsRank().Pluralize(), ph.Hand.fullHousePairRank().Pluralize())
 	}
-	if c.Hand.containsFlush() {
-		return fmt.Sprintf("%s high flush in %s", c.HighestRank().WithArticle(), sortedHand[4].Suit)
+	if ph.Hand.containsFlush() {
+		return fmt.Sprintf("%s high flush in %s", ph.HighestRank().WithArticle(), ph.Hand[4].Suit)
 	}
-	if c.Hand.containsStraight() {
-		if sortedHand[3].Rank == FIVE && sortedHand[4].Rank == ACE {
+	if ph.Hand.containsStraight() {
+		if ph.Hand[3].Rank == FIVE && ph.Hand[4].Rank == ACE {
 			// special case for wheel straight
-			return fmt.Sprintf("%s high straight", sortedHand[3].Rank.WithArticle())
+			return fmt.Sprintf("%s high straight", ph.Hand[3].Rank.WithArticle())
 		}
-		return fmt.Sprintf("%s high straight", c.HighestRank().WithArticle())
+		return fmt.Sprintf("%s high straight", ph.HighestRank().WithArticle())
 	}
-	if c.Hand.containsThreeOfAKind() {
+	if ph.Hand.containsThreeOfAKind() {
 		return fmt.Sprintf(
 			"three %s with %s and %s",
-			c.Hand.threeOfAKindTripsRank().Pluralize(),
-			c.Hand.threeOfAKindFirstKicker().Rank.WithArticle(),
-			c.Hand.threeOfAKindSecondKicker().Rank.WithArticle(),
+			ph.Hand.threeOfAKindTripsRank().Pluralize(),
+			ph.Hand.threeOfAKindFirstKicker().Rank.WithArticle(),
+			ph.Hand.threeOfAKindSecondKicker().Rank.WithArticle(),
 		)
 	}
-	if c.Hand.containsTwoPair() {
+	if ph.Hand.containsTwoPair() {
 		return fmt.Sprintf(
 			"two pair, %s and %s with %s",
-			c.Hand.twoPairBiggestPair().Pluralize(),
-			c.Hand.twoPairSmallestPair().Pluralize(),
-			c.Hand.twoPairKicker().Rank.WithArticle(),
+			ph.Hand.twoPairBiggestPair().Pluralize(),
+			ph.Hand.twoPairSmallestPair().Pluralize(),
+			ph.Hand.twoPairKicker().Rank.WithArticle(),
 		)
 	}
-	if c.Hand.containsPair() {
+	if ph.Hand.containsPair() {
 		return fmt.Sprintf(
 			"a pair of %s with %s, %s, and %s",
-			c.Hand.pairRank().Pluralize(),
-			c.Hand.pairFirstKicker().Rank.WithArticle(),
-			c.Hand.pairSecondKicker().Rank.WithArticle(),
-			c.Hand.pairThirdKicker().Rank.WithArticle(),
+			ph.Hand.pairRank().Pluralize(),
+			ph.Hand.pairFirstKicker().Rank.WithArticle(),
+			ph.Hand.pairSecondKicker().Rank.WithArticle(),
+			ph.Hand.pairThirdKicker().Rank.WithArticle(),
 		)
 	}
 
 	return fmt.Sprintf(
 		// "ace high with an eight, a seven, a six, and a deuce"
 		"%s high with %s, %s, %s, and %s",
-		sortedHand[4].Rank,
-		sortedHand[3].Rank.WithArticle(),
-		sortedHand[2].Rank.WithArticle(),
-		sortedHand[1].Rank.WithArticle(),
-		sortedHand[0].Rank.WithArticle(),
+		ph.Hand[4].Rank,
+		ph.Hand[3].Rank.WithArticle(),
+		ph.Hand[2].Rank.WithArticle(),
+		ph.Hand[1].Rank.WithArticle(),
+		ph.Hand[0].Rank.WithArticle(),
 	)
 }

scoring.go

@@ -1,6 +1,8 @@
 package pokercore
 
-import "fmt"
+import (
+	"fmt"
+)
 
 type HandScore int
 
@@ -22,18 +24,122 @@ func (c Card) Score() HandScore {
 }
 
 func (c Cards) PokerHandScore() (HandScore, error) {
-	if len(c) != 5 {
-		return 0, fmt.Errorf("hand must have 5 cards to be scored as a poker hand")
-	}
 	ph, err := c.PokerHand()
 	if err != nil {
 		return 0, err
 	}
-
-	//fmt.Println(ph)
 	return ph.Score, nil
 }
+
 func (x HandScore) String() string {
 	return fmt.Sprintf("<HandScore %d>", x)
-	//return scoreToName(x)
+}
+
+func (ph *PokerHand) calculateScore() {
+
+	// sanity check, we should only be called in the PokerHand() method from
+	// a Cards, but just in case
+	if len(ph.Hand) != 5 {
+		// normally we don't panic in a library but this is a "should never
+		// happen"
+		panic("PokerHand.calculateScore() called on a PokerHand with != 5 cards")
+	}
+
+	if ph.Hand.containsRoyalFlush() {
+		ph.Type = RoyalFlush
+		ph.Score = ScoreRoyalFlush
+		return
+	}
+
+	if ph.Hand.containsStraightFlush() {
+		ph.Type = StraightFlush
+		ph.Score = ScoreStraightFlush
+		ph.Score += ph.Hand.HighestRank().Score()
+		return
+	}
+
+	if ph.Hand.containsFourOfAKind() {
+		ph.Type = FourOfAKind
+		ph.Score = ScoreFourOfAKind
+		ph.Score += 10000 * ph.Hand.fourOfAKindRank().Score()
+		ph.Score += 100 * ph.Hand.fourOfAKindKicker().Score()
+		return
+	}
+
+	if ph.Hand.containsFullHouse() {
+		ph.Type = FullHouse
+		ph.Score = ScoreFullHouse
+		ph.Score += 10000 * ph.Hand.fullHouseTripsRank().Score()
+		ph.Score += 100 * ph.Hand.fullHousePairRank().Score()
+		return
+	}
+
+	if ph.Hand.containsFlush() {
+		ph.Type = Flush
+		ph.Score = ScoreFlush
+		// flush base score plus sum of card ranks
+		ph.Score += ph.Hand[0].Score()
+		ph.Score += ph.Hand[1].Score()
+		ph.Score += ph.Hand[2].Score()
+		ph.Score += ph.Hand[3].Score()
+		ph.Score += ph.Hand[4].Score()
+		return
+	}
+
+	if ph.Hand.containsStraight() {
+		ph.Type = Straight
+		ph.Score = ScoreStraight
+
+		// note that ph.Hand is already sorted by rank ascending with ace
+		// high
+
+		// Straights are scored by the highest card in the straight
+		// UNLESS the second highest card is a 5 and the highest card is an Ace
+		// In that case, the straight is a 5-high straight, not an Ace-high straight
+		if ph.Hand[3].Rank == FIVE && ph.Hand[4].Rank == ACE {
+			// 5-high straight, scored by the five's rank
+			ph.Score += ph.Hand[3].Score()
+		} else {
+			// All other straights are scored by the highest card in the straight
+			ph.Score += ph.Hand[4].Score()
+		}
+		return
+	}
+
+	if ph.Hand.containsThreeOfAKind() {
+		ph.Type = ThreeOfAKind
+		ph.Score = ScoreThreeOfAKind
+		ph.Score += 10000 * ph.Hand.threeOfAKindTripsRank().Score()
+		ph.Score += 100 * ph.Hand.threeOfAKindFirstKicker().Score()
+		ph.Score += ph.Hand.threeOfAKindSecondKicker().Score()
+		return
+	}
+
+	if ph.Hand.containsTwoPair() {
+		ph.Type = TwoPair
+		ph.Score = ScoreTwoPair
+		ph.Score += 10000 * ph.Hand.twoPairBiggestPair().Score()
+		ph.Score += 100 * ph.Hand.twoPairSmallestPair().Score()
+		ph.Score += ph.Hand.twoPairKicker().Score()
+		return
+	}
+
+	if ph.Hand.containsPair() {
+		ph.Type = Pair
+		ph.Score = ScorePair
+		ph.Score += 10000 * ph.Hand.pairRank().Score()
+		ph.Score += 100 * ph.Hand.pairFirstKicker().Score()
+		ph.Score += ph.Hand.pairSecondKicker().Score()
+		ph.Score += ph.Hand.pairThirdKicker().Score()
+		return
+	}
+
+	ph.Type = HighCard
+	ph.Score = ScoreHighCard // base score
+	// unmade hands are scored like flushes, just add up the values
+	ph.Score += ph.Hand[0].Score()
+	ph.Score += ph.Hand[1].Score()
+	ph.Score += ph.Hand[2].Score()
+	ph.Score += ph.Hand[3].Score()
+	ph.Score += ph.Hand[4].Score()
 }

scoring_test.go

@@ -1,13 +1,74 @@
 package pokercore
 
 import (
-	"fmt"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
 )
 
+func TestHandDescriptionBug(t *testing.T) {
+	t.Parallel()
+	playerCount := 8
+	d := NewDeck()
+	d.ShuffleDeterministically(1337)
+	players := make([]*Cards, playerCount)
+	for i := 0; i < playerCount; i++ {
+		c := d.Deal(2)
+		players[i] = &c
+		t.Logf("Player %d dealt: %+v\n", i+1, c)
+	}
+	t.Logf("Players: %+v\n", players)
+
+	community := d.Deal(5)
+	t.Logf("Community: %+v\n", community)
+
+	var playerResults []*PokerHand
+
+	for i := 0; i < playerCount; i++ {
+		t.Logf("Player %d hole cards: %+v\n", i+1, *players[i])
+		pc := append(*players[i], community...)
+		t.Logf("Player %d cards available: %+v\n", i+1, pc)
+		hand, err := pc.IdentifyBestFiveCardPokerHand()
+		assert.NoError(t, err, "Expected no error")
+		ph, err := hand.PokerHand()
+		assert.NoError(t, err, "Expected no error")
+		t.Logf("Player %d five cards used: %+v\n", i+1, hand)
+		t.Logf("Player %d poker hand: %+v\n", i+1, ph)
+		t.Logf("Player %d best hand description: %s\n", i+1, ph.Description())
+		playerResults = append(playerResults, ph)
+	}
+
+	weirdOne := playerResults[7]
+
+	t.Logf("Weird one: %v\n", weirdOne)
+	t.Logf("Weird one description: %s\n", weirdOne.Description())
+
+	// T♠,7♠,9♦,7♣,T♥
+	assert.Equal(t, "two pair, tens and sevens with a nine", weirdOne.Description())
+
+	scoreShouldBe := ScoreTwoPair
+	scoreShouldBe += 10000 * TEN.Score()
+	scoreShouldBe += 100 * SEVEN.Score()
+	scoreShouldBe += NINE.Score()
+	assert.Equal(t, scoreShouldBe, weirdOne.Score)
+
+	cards := weirdOne.Hand
+
+	assert.True(t, cards.containsTwoPair(), "Expected hand to be two pair")
+
+	bp := cards.twoPairBiggestPair() // returns Rank, because describing a pair
+	assert.Equal(t, TEN, bp, "Expected biggest pair to be a ten")
+
+	sp := cards.twoPairSmallestPair() // returns Rank, because describing a pair
+	assert.Equal(t, SEVEN, sp, "Expected smallest pair to be a seven")
+
+	k := cards.twoPairKicker() // returns Card, because describing a single card
+	assert.Equal(t, NINE, k.Rank, "Expected kicker to be a nine")
+}
+
 func TestAceLowStraight(t *testing.T) {
+	t.Parallel()
+	t.Run("Test Ace-Low Straight", func(t *testing.T) {
 		hand := Cards{
 			AceOfSpades(),
 			DeuceOfHearts(),
@@ -17,21 +78,25 @@ func TestAceLowStraight(t *testing.T) {
 		}
 		assert.True(t, hand.containsStraight(), "Expected hand to be a straight")
 		ph, err := hand.PokerHand()
-	assert.Nil(t, err, "Expected no error")
-	assert.Greater(t, ph.Score, 0, "Expected score to be nonzero 0")
+		assert.NoError(t, err, "Expected no error")
+		assert.Greater(t, ph.Score, 0, "Expected score to be greater than 0")
 		assert.Less(t, ph.Score, 100000000000000000, "Expected score to be less than 100000000000000000")
-	assert.Equal(t, ph.Score, ScoreStraight+100*FIVE.Score())
-	assert.Equal(t, ph.Description(), "a five high straight")
-	assert.True(t, hand.HighestRank() == ACE, "Expected highest rank to be an ace")
-	assert.True(t, hand.SortByRankAscending().First().Rank == DEUCE, "Expected first card to be a deuce")
-	assert.True(t, hand.SortByRankAscending().Last().Rank == ACE, "Expected last card in sorted to be a ace")
-	assert.True(t, hand.SortByRankAscending().Second().Rank == THREE, "Expected second card to be a three")
-	assert.True(t, hand.SortByRankAscending().Third().Rank == FOUR, "Expected third card to be a four")
-	assert.True(t, hand.SortByRankAscending().Fourth().Rank == FIVE, "Expected fourth card to be a five")
-	assert.True(t, hand.SortByRankAscending().Fifth().Rank == ACE, "Expected fifth card to be an ace")
+		assert.Equal(t, ph.Score, ScoreStraight+FIVE.Score())
+		assert.Equal(t, "a five high straight", ph.Description())
+		assert.Equal(t, ACE, hand.HighestRank(), "Expected highest rank to be an ace")
+		s := hand.SortByRankAscending()
+		assert.Equal(t, DEUCE, s.First().Rank, "Expected first card to be a deuce")
+		assert.Equal(t, ACE, s.Last().Rank, "Expected last card in sorted to be an ace")
+		assert.Equal(t, THREE, s.Second().Rank, "Expected second card to be a three")
+		assert.Equal(t, FOUR, s.Third().Rank, "Expected third card to be a four")
+		assert.Equal(t, FIVE, s.Fourth().Rank, "Expected fourth card to be a five")
+		assert.Equal(t, ACE, s.Fifth().Rank, "Expected fifth card to be an ace")
+	})
 }
 
 func TestAceHighStraight(t *testing.T) {
+	t.Parallel()
+	t.Run("Test Ace-High Straight", func(t *testing.T) {
 		hand := Cards{
 			TenOfSpades(),
 			JackOfHearts(),
@@ -45,16 +110,19 @@ func TestAceHighStraight(t *testing.T) {
 		newDeck.ShuffleDeterministically(123456789)
 		shuffledHand := newDeck.Deal(5)
 		assert.True(t, shuffledHand.containsStraight(), "Expected hand to still be a straight after shuffle")
-	assert.True(t, shuffledHand.HighestRank() == ACE, "Expected highest rank to be an ace")
+		assert.Equal(t, ACE, shuffledHand.HighestRank(), "Expected highest rank to be an ace")
 		sortedHand := shuffledHand.SortByRankAscending()
-	assert.True(t, sortedHand[0].Rank == TEN, "Expected lowest rank to be a ten")
-	assert.True(t, sortedHand[1].Rank == JACK, "Expected second lowest rank to be a jack")
-	assert.True(t, sortedHand[2].Rank == QUEEN, "Expected third lowest rank to be a queen")
-	assert.True(t, sortedHand[3].Rank == KING, "Expected fourth lowest rank to be a king")
-	assert.True(t, sortedHand[4].Rank == ACE, "Expected highest rank to be an ace")
+		assert.Equal(t, TEN, sortedHand[0].Rank, "Expected lowest rank to be a ten")
+		assert.Equal(t, JACK, sortedHand[1].Rank, "Expected second lowest rank to be a jack")
+		assert.Equal(t, QUEEN, sortedHand[2].Rank, "Expected third lowest rank to be a queen")
+		assert.Equal(t, KING, sortedHand[3].Rank, "Expected fourth lowest rank to be a king")
+		assert.Equal(t, ACE, sortedHand[4].Rank, "Expected highest rank to be an ace")
+	})
 }
 
 func TestOtherStraight(t *testing.T) {
+	t.Parallel()
+	t.Run("Test Other Straight", func(t *testing.T) {
 		hand := Cards{
 			DeuceOfSpades(),
 			ThreeOfHearts(),
@@ -66,15 +134,18 @@ func TestOtherStraight(t *testing.T) {
 
 		newDeck := NewDeckFromCards(hand)
 		newDeck.ShuffleDeterministically(123456789)
-	fmt.Printf("Shuffled deck: %s\n", newDeck.String())
-	fmt.Printf("new deck has %d cards\n", newDeck.Count())
 		shuffledHand := newDeck.Deal(5)
 		assert.True(t, shuffledHand.containsStraight(), "Expected hand to still be a straight after shuffle")
 		assert.False(t, shuffledHand.containsTwoPair(), "Expected hand to not be two pair")
-
+		assert.False(t, shuffledHand.containsPair(), "Expected hand to not be a pair")
+		assert.Equal(t, SIX, shuffledHand.HighestRank(), "Expected highest rank to be a six")
+		assert.Equal(t, DEUCE, shuffledHand.SortByRankAscending().First().Rank, "Expected first card to be a deuce")
+	})
 }
 
 func TestFlush(t *testing.T) {
+	t.Parallel()
+	t.Run("Test Flush", func(t *testing.T) {
 		hand := Cards{
 			AceOfSpades(),
 			DeuceOfSpades(),
@@ -85,24 +156,27 @@ func TestFlush(t *testing.T) {
 		assert.True(t, hand.containsFlush(), "Expected hand to be a flush")
 		newDeck := NewDeckFromCards(hand)
 		newDeck.ShuffleDeterministically(123456789)
-	fmt.Printf("Shuffled deck: %s\n", newDeck.String())
-	fmt.Printf("new deck has %d cards\n", newDeck.Count())
 		shuffledHand := newDeck.Deal(5)
 		assert.True(t, shuffledHand.containsFlush(), "Expected hand to still be a flush after shuffle")
 
+		// flush value is the sum of the ranks, just like high card
 		x := ScoreFlush
-	var multiplier HandScore = 100
-	x += multiplier * DEUCE.Score()
-	multiplier *= 100
-	x += multiplier * THREE.Score()
-	multiplier *= 100
-	x += multiplier * FOUR.Score()
-	multiplier *= 100
-	x += multiplier * SIX.Score()
-	fmt.Printf("a-2-3-4-6 flush score should be: %d\n", x)
+		x += ACE.Score()
+		x += DEUCE.Score()
+		x += THREE.Score()
+		x += FOUR.Score()
+		x += SIX.Score()
+
+		ph, err := shuffledHand.PokerHand()
+		assert.NoError(t, err, "Expected no error")
+		assert.Greater(t, ph.Score, 0, "Expected score to be nonzero")
+		assert.Equal(t, ph.Score, x)
+	})
 }
 
 func TestStraightFlush(t *testing.T) {
+	t.Parallel()
+	t.Run("Test Straight Flush", func(t *testing.T) {
 		hand := Cards{
 			SixOfSpades(),
 			DeuceOfSpades(),
@@ -120,19 +194,52 @@ func TestStraightFlush(t *testing.T) {
 		assert.False(t, hand.containsTwoPair(), "Expected hand to not be two pair")
 		assert.False(t, hand.containsPair(), "Expected hand to not be a pair")
 
-	assert.True(t, hand.HighestRank() == SIX, "Expected highest rank to be a six")
+		assert.Equal(t, SIX, hand.HighestRank(), "Expected highest rank to be a six")
 
 		nd := NewDeckFromCards(hand)
 		nd.ShuffleDeterministically(123456789)
-	fmt.Printf("Shuffled deck: %s\n", nd.String())
-	fmt.Printf("new deck has %d cards\n", nd.Count())
 		shuffledHand := nd.Deal(5)
 		assert.True(t, shuffledHand.containsStraightFlush(), "Expected hand to still be a straight flush after shuffle")
-	assert.True(t, shuffledHand.HighestRank() == SIX, "Expected highest rank to still be a six after shuffle")
-	assert.True(t, shuffledHand.HighestRank() == SIX, "Expected highest rank to be a six after shuffle even with aces low")
+		assert.Equal(t, SIX, shuffledHand.HighestRank(), "Expected highest rank to still be a six after shuffle")
+		assert.Equal(t, SIX, shuffledHand.HighestRank(), "Expected highest rank to be a six after shuffle even with aces low")
+	})
+}
+
+func TestFourOfAKind(t *testing.T) {
+	t.Parallel()
+	t.Run("Test Four of a Kind", func(t *testing.T) {
+		hand := Cards{
+			SixOfSpades(),
+			SixOfHearts(),
+			SixOfDiamonds(),
+			SixOfClubs(),
+			FiveOfSpades(),
+		}
+		assert.False(t, hand.containsStraight(), "Expected hand to not be a straight")
+		assert.False(t, hand.containsFlush(), "Expected hand to not be a flush")
+		assert.False(t, hand.containsStraightFlush(), "Expected hand to not be a straight flush")
+		assert.False(t, hand.containsRoyalFlush(), "Expected hand to not be a royal flush")
+		assert.True(t, hand.containsFourOfAKind(), "Expected hand to be four of a kind")
+		assert.False(t, hand.containsFullHouse(), "Expected hand to not be a full house")
+
+		// note that these are *expected* to be true. the contains* functions
+		// are used in the PokerHand.calculateScore method to determine the best hand
+		// and are checked in sequence of descending value, so if a hand is four of a kind
+		// it will not be checked for full house, three of a kind, etc.
+
+		// technically quads *is* two pair also, and a hand with quads does
+		// indeed contain three of a kind, and contains a pair.
+		assert.True(t, hand.containsThreeOfAKind(), "Expected hand to contain three of a kind")
+		assert.True(t, hand.containsTwoPair(), "Expected hand to contain two pair")
+		assert.True(t, hand.containsPair(), "Expected hand to contain a pair")
+
+		assert.Equal(t, SIX, hand.HighestRank(), "Expected highest rank to be a six")
+	})
 }
 
 func TestRoyalFlush(t *testing.T) {
+	t.Parallel()
+	t.Run("Test Royal Flush", func(t *testing.T) {
 		hand := Cards{
 			TenOfSpades(),
 			JackOfSpades(),
@@ -151,11 +258,14 @@ func TestRoyalFlush(t *testing.T) {
 		assert.False(t, hand.containsTwoPair(), "Expected hand to not be two pair")
 		assert.False(t, hand.containsPair(), "Expected hand to not be a pair")
 
-	assert.True(t, hand.HighestRank() == ACE, "Expected highest rank to be an ace")
-	assert.False(t, hand.HighestRank() == TEN, "Expected highest rank to not be an ace")
+		assert.Equal(t, ACE, hand.HighestRank(), "Expected highest rank to be an ace")
+		assert.NotEqual(t, TEN, hand.HighestRank(), "Expected highest rank to not be a ten")
+	})
 }
 
 func TestUnmadeHand(t *testing.T) {
+	t.Parallel()
+	t.Run("Test Unmade Hand", func(t *testing.T) {
 		hand := Cards{
 			TenOfSpades(),
 			JackOfDiamonds(),
@@ -172,11 +282,14 @@ func TestUnmadeHand(t *testing.T) {
 		assert.False(t, hand.containsThreeOfAKind(), "Expected hand to not be three of a kind")
 		assert.False(t, hand.containsTwoPair(), "Expected hand to not be two pair")
 		assert.False(t, hand.containsPair(), "Expected hand to not be a pair")
-	assert.True(t, hand.HighestRank() == KING, "Expected highest rank to be a king")
+		assert.Equal(t, KING, hand.HighestRank(), "Expected highest rank to be a king")
 		assert.True(t, hand.isUnmadeHand(), "Expected hand to be unmade")
+	})
 }
 
 func TestTwoPair(t *testing.T) {
+	t.Parallel()
+	t.Run("Test Two Pair", func(t *testing.T) {
 		hand := Cards{
 			KingOfSpades(),
 			JackOfDiamonds(),
@@ -193,11 +306,28 @@ func TestTwoPair(t *testing.T) {
 		assert.False(t, hand.containsThreeOfAKind(), "Expected hand to not be three of a kind")
 		assert.True(t, hand.containsTwoPair(), "Expected hand to be two pair")
 		assert.True(t, hand.containsPair(), "Expected hand to also be a pair")
-	assert.True(t, hand.HighestRank() == KING, "Expected highest rank to be a king")
+		assert.Equal(t, KING, hand.HighestRank(), "Expected highest rank to be a king")
 		assert.False(t, hand.isUnmadeHand(), "Expected hand to not be unmade")
+	})
+}
+
+func TestDetectDuplicates(t *testing.T) {
+	t.Parallel()
+	t.Run("Test Detect Duplicates", func(t *testing.T) {
+		hand := Cards{
+			KingOfSpades(),
+			JackOfDiamonds(),
+			JackOfSpades(),
+			KingOfSpades(),
+			TenOfSpades(),
+		}
+		assert.True(t, hand.containsDuplicates(), "Expected hand to contain duplicates")
+	})
 }
 
 func TestHandScore(t *testing.T) {
+	t.Parallel()
+	t.Run("Test Hand Score", func(t *testing.T) {
 		hand := Cards{
 			KingOfSpades(),
 			JackOfDiamonds(),
@@ -206,26 +336,88 @@ func TestHandScore(t *testing.T) {
 			TenOfSpades(),
 		}
 
-	ph, error := hand.PokerHand()
-	assert.Nil(t, error, "Expected no error")
-	assert.True(t, ph.Score > 0, "Expected score to be nonzero 0")
+		ph, err := hand.PokerHand()
+		assert.NoError(t, err, "Expected no error")
+		assert.True(t, ph.Score > 0, "Expected score to be nonzero")
 		assert.True(t, ph.Score < 100000000000000000, "Expected score to be less than 100000000000000000")
-
-	fmt.Printf("PokerHand: %v+\n", ph)
-	fmt.Printf("PH score: %d\n", ph.Score)
+		// write more assertions FIXME
+	})
 }
 
 func TestTwoPairBug(t *testing.T) {
+	t.Parallel()
+	t.Run("Test Two Pair Bug", func(t *testing.T) {
 		// this is an actual bug in the first implementation
 		c, err := NewCardsFromString("9♠,9♣,Q♥,Q♦,K♣")
-	assert.Nil(t, err, "Expected no error")
+		assert.NoError(t, err, "Expected no error")
 
 		ph, err := c.PokerHand()
-	assert.Nil(t, err, "Expected no error")
-	assert.Greater(t, ph.Score, 0, "Expected score to be nonzero 0")
+		assert.NoError(t, err, "Expected no error")
+		assert.Greater(t, ph.Score, 0, "Expected score to be nonzero")
 		desc := ph.Description()
-	assert.Equal(t, desc, "two pair, queens and nines with a king")
-
-	fmt.Printf("PokerHand: %v+\n", ph)
-	fmt.Printf("PH score: %d\n", ph.Score)
+		assert.Equal(t, "two pair, queens and nines with a king", desc)
+	})
+}
+
+func TestScoringStructureQuads(t *testing.T) {
+	t.Parallel()
+	t.Run("Test Scoring Structure Quads", func(t *testing.T) {
+		// this test case was for a bug, but is now fixed
+		handA := Cards{
+			DeuceOfSpades(),
+			DeuceOfHearts(),
+			DeuceOfDiamonds(),
+			DeuceOfClubs(),
+			AceOfSpades(),
+		}
+
+		handB := Cards{
+			ThreeOfSpades(),
+			ThreeOfHearts(),
+			ThreeOfDiamonds(),
+			ThreeOfClubs(),
+			DeuceOfSpades(),
+		}
+
+		phA, err := handA.PokerHand()
+		assert.NoError(t, err, "Expected no error")
+		phB, err := handB.PokerHand()
+		assert.NoError(t, err, "Expected no error")
+		assert.Greater(t, phB.Score, phA.Score, "Expected hand B to be higher than hand A")
+	})
+}
+
+func TestScoringStructureFullHouse(t *testing.T) {
+	t.Parallel()
+	t.Run("Test Scoring Structure Full House", func(t *testing.T) {
+		// this test case documents an actual bug i found in my scoring code
+		// related to the fact that i was multiplying by 100 then by 1000,
+		// instead of by 100 then by 10000 in the scoring. because the ranks
+		// are 2-14, the different levels of kickers (or in the case of a full
+		// house, the pair) were not distinguishing sufficiently.
+		handA := Cards{
+			DeuceOfSpades(),
+			DeuceOfHearts(),
+			DeuceOfDiamonds(),
+			AceOfSpades(),
+			AceOfHearts(),
+		}
+
+		phA, err := handA.PokerHand()
+		assert.NoError(t, err, "Expected no error")
+		deucesFullOfAcesScore := phA.Score
+
+		handB := Cards{
+			ThreeOfSpades(),
+			ThreeOfHearts(),
+			ThreeOfDiamonds(),
+			DeuceOfSpades(),
+			DeuceOfHearts(),
+		}
+		phB, err := handB.PokerHand()
+		assert.NoError(t, err, "Expected no error")
+		threesFullOfDeucesScore := phB.Score
+
+		assert.Greater(t, threesFullOfDeucesScore, deucesFullOfAcesScore, "Expected Threes full of deuces to beat deuces full of aces")
+	})
 }