feat: add Done to test state

future.go

@@ -142,6 +142,10 @@ func (p *Promise[T]) Future() *Future[T] {
 	return &Future[T]{state: &p.state}
 }
 
+func (p *Promise[T]) Done() bool {
+	return isDone(atomic.LoadUint64(&p.state.state))
+}
+
 func (f *Future[T]) Get() (T, error) {
 	return f.state.get()
 }
@@ -158,6 +162,10 @@ func (f *Future[T]) Subscribe(cb func(val T, err error)) {
 	f.state.subscribe(cb)
 }
 
+func (f *Future[T]) Done() bool {
+	return isDone(atomic.LoadUint64(&f.state.state))
+}
+
 func isFree(st uint64) bool {
 	return ((st & maskState) >> 32) == stateFree
 }

future_test.go

@@ -74,6 +74,17 @@ func TestFutureSubscribe(t *testing.T) {
 	assert.Equal(t, val2, 3)
 }
 
+func TestPromiseFutureDone(t *testing.T) {
+	p := NewPromise[int]()
+	f := p.Future()
+	assert.False(t, p.Done())
+	assert.False(t, f.Done())
+
+	p.Set(1, nil)
+	assert.True(t, p.Done())
+	assert.True(t, f.Done())
+}
+
 func Benchmark(b *testing.B) {
 	b.Run("Promise", func(b *testing.B) {
 		for i := 0; i < b.N; i++ {