refactor(webhook): extract async context detach into a helper

pkg/modules/webhook/async_context_test.go

@@ -0,0 +1,56 @@
+package webhook
+
+import (
+	"context"
+	"testing"
+	"time"
+
+	"github.com/gotenberg/gotenberg/v8/pkg/modules/api"
+)
+
+func TestDetachAsyncContext_PreservesDeadline(t *testing.T) {
+	deadline := time.Now().Add(2 * time.Hour)
+	reqCtx, reqCancel := context.WithDeadline(context.Background(), deadline)
+	defer reqCancel()
+
+	ctx := &api.Context{Context: reqCtx}
+	cancel := detachAsyncContext(ctx, func() {})
+	defer cancel()
+
+	got, ok := ctx.Deadline()
+	if !ok {
+		t.Fatal("expected the detached context to keep a deadline")
+	}
+	if !got.Equal(deadline) {
+		t.Errorf("expected deadline %v, got %v", deadline, got)
+	}
+}
+
+func TestDetachAsyncContext_SurvivesRequestCancellation(t *testing.T) {
+	reqCtx, reqCancel := context.WithDeadline(context.Background(), time.Now().Add(2*time.Hour))
+
+	ctx := &api.Context{Context: reqCtx}
+	cancel := detachAsyncContext(ctx, func() {})
+	defer cancel()
+
+	// Cancelling the inbound request must not abort the detached context.
+	reqCancel()
+
+	if err := ctx.Err(); err != nil {
+		t.Errorf("expected the detached context to survive request cancellation, got %v", err)
+	}
+}
+
+func TestDetachAsyncContext_CancelInvokesOriginal(t *testing.T) {
+	reqCtx, reqCancel := context.WithDeadline(context.Background(), time.Now().Add(time.Hour))
+	defer reqCancel()
+
+	called := 0
+	ctx := &api.Context{Context: reqCtx}
+	cancel := detachAsyncContext(ctx, func() { called++ })
+
+	cancel()
+	if called != 1 {
+		t.Errorf("expected the original cancel to be invoked once, got %d", called)
+	}
+}