(new): expand runtime APIs

(fix): harden concurrent lifecycle
(tests): add regression coverage
(doc): update v1.2 guidance

observer_async_test.go

@@ -0,0 +1,59 @@
+package laniakea
+
+import (
+	"context"
+	"errors"
+	"testing"
+	"time"
+)
+
+type cancelAwareObserver struct {
+	testObserver
+	started chan struct{}
+}
+
+func (o *cancelAwareObserver) OnUpdateReceived(ctx context.Context, _ UpdateReceivedEvent) {
+	close(o.started)
+	<-ctx.Done()
+}
+
+type stubbornObserver struct {
+	testObserver
+	started chan struct{}
+	release chan struct{}
+}
+
+func (o *stubbornObserver) OnUpdateReceived(context.Context, UpdateReceivedEvent) {
+	close(o.started)
+	<-o.release
+}
+
+func TestObserverDispatcherCancelsCallbackDuringClose(t *testing.T) {
+	observer := &cancelAwareObserver{started: make(chan struct{})}
+	dispatcher := newObserverDispatcher(observer, nil)
+	dispatcher.enqueue(context.Background(), UpdateReceivedEvent{})
+	<-observer.started
+
+	ctx, cancel := context.WithTimeout(context.Background(), time.Second)
+	defer cancel()
+	if err := dispatcher.close(ctx); err != nil {
+		t.Fatalf("close returned error: %v", err)
+	}
+}
+
+func TestObserverDispatcherCloseTimeout(t *testing.T) {
+	observer := &stubbornObserver{started: make(chan struct{}), release: make(chan struct{})}
+	dispatcher := newObserverDispatcher(observer, nil)
+	dispatcher.enqueue(context.Background(), UpdateReceivedEvent{})
+	<-observer.started
+
+	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Millisecond)
+	defer cancel()
+	if err := dispatcher.close(ctx); !errors.Is(err, ErrObserverShutdownTimeout) {
+		t.Fatalf("close error = %v, want ErrObserverShutdownTimeout", err)
+	}
+	close(observer.release)
+	if err := dispatcher.close(context.Background()); err != nil {
+		t.Fatalf("second close returned error: %v", err)
+	}
+}