future_test.go

package syncx

import (
	"context"
	"errors"
	"testing"
	"time"
)

func TestFutureAwaitSuccess(t *testing.T) {
	f := NewFuture(func() (int, error) {
		return 42, nil
	})
	v, err := f.Await(context.Background())
	if err != nil {
		t.Fatalf("unexpected error: %v", err)
	}
	if v != 42 {
		t.Fatalf("got %d want 42", v)
	}
}

func TestFutureAwaitRepeated(t *testing.T) {
	f := NewFuture(func() (int, error) {
		return 42, nil
	})
	<-f.Done()
	for i := 0; i < 3; i++ {
		v, err := f.Await(context.Background())
		if err != nil || v != 42 {
			t.Fatalf("await %d: got (%d, %v), want (42, nil)", i, v, err)
		}
	}
}

func TestFutureAwaitCanceled(t *testing.T) {
	f := NewFuture(func() (int, error) {
		time.Sleep(50 * time.Millisecond)
		return 1, nil
	})
	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Millisecond)
	defer cancel()
	_, err := f.Await(ctx)
	if !errors.Is(err, context.DeadlineExceeded) {
		t.Fatalf("expected deadline exceeded, got %v", err)
	}
}