yoloyolo/synth/envelope_test.go

package synth_test

import (
	"testing"

	"github.com/netsynth/netsynth/synth"
)

func TestEnvelopeStartsIdle(t *testing.T) {
	env := synth.NewEnvelope(synth.SustainedEnvParams, synth.SampleRate, 1.0)
	if env.State() != synth.EnvIdle {
		t.Errorf("expected EnvIdle, got %v", env.State())
	}
	if env.Level() != 0 {
		t.Errorf("expected level=0 in idle, got %v", env.Level())
	}
}

func TestEnvelopeTriggerStartsAttack(t *testing.T) {
	env := synth.NewEnvelope(synth.SustainedEnvParams, synth.SampleRate, 1.0)
	env.Trigger()
	if env.State() != synth.EnvAttack {
		t.Errorf("expected EnvAttack after Trigger, got %v", env.State())
	}
}

func TestEnvelopeAttackReachesPeak(t *testing.T) {
	env := synth.NewEnvelope(synth.SustainedEnvParams, synth.SampleRate, 1.0)
	env.Trigger()
	// Advance through the full attack phase (2 seconds)
	for i := 0; i < synth.SampleRate*3; i++ {
		env.Advance()
	}
	if env.Level() < 0.8 {
		t.Errorf("expected level >= 0.8 after attack, got %v", env.Level())
	}
}

func TestEnvelopeReleaseDecays(t *testing.T) {
	env := synth.NewEnvelope(synth.SustainedEnvParams, synth.SampleRate, 1.0)
	env.Trigger()
	// Build up
	for i := 0; i < synth.SampleRate*3; i++ {
		env.Advance()
	}
	peakLevel := env.Level()

	env.Release()
	// Advance through release (4 seconds)
	for i := 0; i < synth.SampleRate*6; i++ {
		env.Advance()
	}
	if env.Level() >= peakLevel*0.3 {
		t.Errorf("expected level to decay well below peak after release, peak=%v, current=%v", peakLevel, env.Level())
	}
}

func TestBurstyEnvelopeNoSustain(t *testing.T) {
	env := synth.NewEnvelope(synth.BurstyEnvParams, synth.SampleRate, 1.0)
	env.Trigger()
	// Advance 2 seconds — bursty should have attacked, decayed (sustain=0), and be releasing
	for i := 0; i < synth.SampleRate*2; i++ {
		env.Advance()
	}
	// Should be very quiet (in release or idle)
	if env.Level() > 0.1 {
		t.Errorf("bursty envelope should be near zero after 2s, got %v (state=%v)", env.Level(), env.State())
	}
}

func TestEnvelopeIdleOutputsZero(t *testing.T) {
	env := synth.NewEnvelope(synth.SustainedEnvParams, synth.SampleRate, 1.0)
	for i := 0; i < 100; i++ {
		val := env.Advance()
		if val != 0 {
			t.Errorf("idle envelope should output 0, got %v at sample %d", val, i)
			break
		}
	}
}

func TestEnvelopeRetriggerFromRelease(t *testing.T) {
	env := synth.NewEnvelope(synth.SustainedEnvParams, synth.SampleRate, 1.0)
	env.Trigger()
	for i := 0; i < synth.SampleRate*3; i++ {
		env.Advance()
	}
	env.Release()
	for i := 0; i < synth.SampleRate; i++ {
		env.Advance()
	}
	levelBeforeRetrigger := env.Level()

	// Re-trigger
	env.Trigger()
	for i := 0; i < synth.SampleRate*3; i++ {
		env.Advance()
	}
	if env.Level() <= levelBeforeRetrigger {
		t.Errorf("re-triggered envelope should rise above release level, before=%v, after=%v",
			levelBeforeRetrigger, env.Level())
	}
}