package coalesce

import (
	"context"
	"errors"
	"sync"
	"testing"
)

func TestSignalCoalescesConcurrentNotifications(t *testing.T) {
	signal := NewSignal()

	var wg sync.WaitGroup
	for range 100 {
		wg.Add(1)
		go func() {
			defer wg.Done()
			signal.Notify()
		}()
	}
	wg.Wait()

	if err := signal.Wait(context.Background()); err != nil {
		t.Fatalf("Wait(): %v", err)
	}

	ctx, cancel := context.WithCancel(context.Background())
	cancel()
	if err := signal.Wait(ctx); !errors.Is(err, context.Canceled) {
		t.Fatalf("second Wait() error = %v, want context.Canceled", err)
	}
}