8fccbb2a9a
Seed expansion uses SplitMix64 so all 32 seed bytes affect the stream; copying the seed directly into xoshiro state left the first draw dependent only on bytes 8-15. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
98 lines
2.4 KiB
Go
98 lines
2.4 KiB
Go
package sim
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import (
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"testing"
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"github.com/drjones/quantum-arcade/pkg/fixed"
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)
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func TestCrashPointNeverBelowOne(t *testing.T) {
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for i := 0; i < 20000; i++ {
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var seed [32]byte
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seed[0], seed[1] = byte(i), byte(i>>8)
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if cp := CrashPoint(seed); cp < 1<<32 {
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t.Fatalf("seed %d: crash point %v below 1.0", i, cp)
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}
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}
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}
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func TestCrashPointIsDeterministic(t *testing.T) {
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var seed [32]byte
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copy(seed[:], "repeatable")
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first := CrashPoint(seed)
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for i := 0; i < 100; i++ {
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if got := CrashPoint(seed); got != first {
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t.Fatalf("run %d: %v != %v", i, got, first)
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}
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}
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}
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// With a 2% house edge, a player cashing out at exactly 2.00x should win
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// slightly under half the time. This pins the payout distribution.
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func TestHouseEdgeAtTwoX(t *testing.T) {
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const n = 200000
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target := int64(2) << 32
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wins := 0
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for i := 0; i < n; i++ {
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var seed [32]byte
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seed[0], seed[1], seed[2] = byte(i), byte(i>>8), byte(i>>16)
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if int64(CrashPoint(seed)) >= target {
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wins++
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}
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}
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pct := float64(wins) * 100 / n
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if pct < 47.5 || pct > 50.5 {
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t.Fatalf("win rate at 2.00x = %.2f%%, want ~49%%", pct)
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}
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}
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// The expected return at any cash-out target should be about 98%.
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func TestExpectedReturnMatchesEdge(t *testing.T) {
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const n = 200000
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for _, targetX := range []int64{2, 3, 5} {
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target := targetX << 32
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var returned float64
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for i := 0; i < n; i++ {
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var seed [32]byte
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seed[0], seed[1], seed[2], seed[3] = byte(i), byte(i>>8), byte(i>>16), byte(targetX)
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if int64(CrashPoint(seed)) >= target {
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returned += float64(targetX)
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}
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}
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rtp := returned * 100 / n
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if rtp < 96.0 || rtp > 100.0 {
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t.Fatalf("RTP at %dx = %.2f%%, want ~98%%", targetX, rtp)
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}
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}
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}
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func TestMultiplierStartsAtOne(t *testing.T) {
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if got := MultiplierAt(0); got != 1<<32 {
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t.Fatalf("MultiplierAt(0) = %v, want 1.0", got)
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}
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}
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func TestMultiplierIsMonotonic(t *testing.T) {
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prev := MultiplierAt(0)
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for tick := 1; tick < 5000; tick++ {
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cur := MultiplierAt(tick)
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if cur < prev {
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t.Fatalf("tick %d: multiplier decreased %v -> %v", tick, prev, cur)
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}
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prev = cur
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}
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}
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func TestTicksToMultiplierRoundTrips(t *testing.T) {
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for _, m := range []int64{2, 5, 10} {
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target := fixed.FromInt(m)
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tick := TicksToMultiplier(target)
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if MultiplierAt(tick) < target {
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t.Fatalf("tick %d does not reach %dx", tick, m)
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}
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if tick > 0 && MultiplierAt(tick-1) >= target {
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t.Fatalf("tick %d is not the first to reach %dx", tick, m)
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}
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}
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}
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