Add parameters for food spawn chance and min food.

standard.go

@@ -6,15 +6,16 @@ import (
 	"sort"
 )
 
-type StandardRuleset struct{}
+type StandardRuleset struct {
+	FoodSpawnChance int32 // [0, 100]
+	MinimumFood     int32
+}
 
 const (
 	BoardSizeSmall  = 7
 	BoardSizeMedium = 11
 	BoardSizeLarge  = 19
 
-	FoodSpawnChance = 0.15
-
 	SnakeMaxHealth = 100
 	SnakeStartSize = 3
 
@@ -173,7 +174,7 @@ func (r *StandardRuleset) placeFoodFixed(b *BoardState) error {
 }
 
 func (r *StandardRuleset) placeFoodRandomly(b *BoardState) error {
-	return r.spawnFood(b, len(b.Snakes))
+	return r.spawnFood(b, int32(len(b.Snakes)))
 }
 
 func (r *StandardRuleset) isKnownBoardSize(b *BoardState) bool {
@@ -518,14 +519,17 @@ func (r *StandardRuleset) growSnake(snake *Snake) {
 }
 
 func (r *StandardRuleset) maybeSpawnFood(b *BoardState) error {
-	if len(b.Food) == 0 || rand.Float32() <= FoodSpawnChance {
+	numCurrentFood := int32(len(b.Food))
+	if numCurrentFood < r.MinimumFood {
+		return r.spawnFood(b, r.MinimumFood-numCurrentFood)
+	} else if r.FoodSpawnChance > 0 && int32(rand.Intn(100)) < r.FoodSpawnChance {
 		return r.spawnFood(b, 1)
 	}
 	return nil
 }
 
-func (r *StandardRuleset) spawnFood(b *BoardState, n int) error {
-	for i := 0; i < n; i++ {
+func (r *StandardRuleset) spawnFood(b *BoardState, n int32) error {
+	for i := int32(0); i < n; i++ {
 		unoccupiedPoints := r.getUnoccupiedPoints(b, false)
 		if len(unoccupiedPoints) > 0 {
 			newFood := unoccupiedPoints[rand.Intn(len(unoccupiedPoints))]

standard_test.go

@@ -1828,22 +1828,89 @@ func TestGetEvenUnoccupiedPoints(t *testing.T) {
 	}
 }
 
-func TestMaybeSpawnFood(t *testing.T) {
+func TestMaybeSpawnFoodMinimum(t *testing.T) {
+	tests := []struct {
+		MinimumFood  int32
+		Food         []Point
+		ExpectedFood int
+	}{
+		// Use pre-tested seeds and results
+		{0, []Point{}, 0},
+		{1, []Point{}, 1},
+		{9, []Point{}, 9},
+		{7, []Point{{4, 5}, {4, 4}, {4, 1}}, 7},
+	}
+
+	for _, test := range tests {
+		r := StandardRuleset{MinimumFood: test.MinimumFood}
+		b := &BoardState{
+			Height: 11,
+			Width:  11,
+			Snakes: []Snake{
+				{Body: []Point{{1, 0}, {1, 1}}},
+				{Body: []Point{{0, 1}, {0, 2}, {0, 3}}},
+			},
+			Food: test.Food,
+		}
+
+		err := r.maybeSpawnFood(b)
+		require.NoError(t, err)
+		require.Equal(t, test.ExpectedFood, len(b.Food))
+	}
+}
+
+func TestMaybeSpawnFoodZeroChance(t *testing.T) {
+	r := StandardRuleset{FoodSpawnChance: 0}
+	b := &BoardState{
+		Height: 11,
+		Width:  11,
+		Snakes: []Snake{
+			{Body: []Point{{1, 0}, {1, 1}}},
+			{Body: []Point{{0, 1}, {0, 2}, {0, 3}}},
+		},
+		Food: []Point{},
+	}
+	for i := 0; i < 1000; i++ {
+		err := r.maybeSpawnFood(b)
+		require.NoError(t, err)
+		require.Equal(t, len(b.Food), 0)
+	}
+}
+
+func TestMaybeSpawnFoodHundredChance(t *testing.T) {
+	r := StandardRuleset{FoodSpawnChance: 100}
+	b := &BoardState{
+		Height: 11,
+		Width:  11,
+		Snakes: []Snake{
+			{Body: []Point{{1, 0}, {1, 1}}},
+			{Body: []Point{{0, 1}, {0, 2}, {0, 3}}},
+		},
+		Food: []Point{},
+	}
+	for i := 1; i <= 22; i++ {
+		err := r.maybeSpawnFood(b)
+		require.NoError(t, err)
+		require.Equal(t, i, len(b.Food))
+	}
+}
+
+func TestMaybeSpawnFoodHalfChance(t *testing.T) {
 	tests := []struct {
 		Seed         int64
 		Food         []Point
-		ExpectedFood []Point
+		ExpectedFood int32
 	}{
 		// Use pre-tested seeds and results
-		{123, []Point{}, []Point{{2, 3}}},
-		{456, []Point{{4, 4}}, []Point{{4, 4}}},
-		{789, []Point{{4, 4}}, []Point{{4, 4}}},
-		{1024, []Point{}, []Point{{1, 2}}},
-		{511, []Point{{4, 4}}, []Point{{4, 4}, {4, 1}}},
-		{165, []Point{{4, 4}}, []Point{{4, 4}, {4, 2}}},
+		{123, []Point{}, 1},
+		{12345, []Point{}, 0},
+		{456, []Point{{4, 4}}, 1},
+		{789, []Point{{4, 4}}, 2},
+		{511, []Point{{4, 4}}, 1},
+		{165, []Point{{4, 4}}, 2},
 	}
 
-	r := StandardRuleset{}
+	r := StandardRuleset{FoodSpawnChance: 50}
 	for _, test := range tests {
 		b := &BoardState{
 			Height: 4,
@@ -1858,10 +1925,7 @@ func TestMaybeSpawnFood(t *testing.T) {
 		rand.Seed(test.Seed)
 		err := r.maybeSpawnFood(b)
 		require.NoError(t, err)
-		require.Equal(t, len(test.ExpectedFood), len(b.Food), "Seed %d", test.Seed)
-		for i, e := range test.ExpectedFood {
-			require.Equal(t, e, b.Food[i], "Seed %d", test.Seed)
-		}
+		require.Equal(t, test.ExpectedFood, int32(len(b.Food)), "Seed %d", test.Seed)
 	}
 }