test: add regression test for 5691

With `CallbackScope`, this has become possible to do properly.

Fixes: nodejs/node#5691
PR-URL: nodejs/node#14697
Reviewed-By: James M Snell <jasnell@gmail.com>

test/addons/callback-scope/binding.cc

@@ -1,5 +1,6 @@
 #include "node.h"
 #include "v8.h"
+#include "uv.h"
 
 #include <assert.h>
 #include <vector>
@@ -30,8 +31,39 @@ void RunInCallbackScope(const v8::FunctionCallbackInfo<v8::Value>& args) {
     args.GetReturnValue().Set(ret.ToLocalChecked());
 }
 
+static v8::Persistent<v8::Promise::Resolver> persistent;
+
+static void Callback(uv_work_t* req, int ignored) {
+  v8::Isolate* isolate = v8::Isolate::GetCurrent();
+  v8::HandleScope scope(isolate);
+  node::CallbackScope callback_scope(isolate, v8::Object::New(isolate), {0, 0});
+
+  v8::Local<v8::Promise::Resolver> local =
+      v8::Local<v8::Promise::Resolver>::New(isolate, persistent);
+  local->Resolve(v8::Undefined(isolate));
+  delete req;
+}
+
+static void TestResolveAsync(const v8::FunctionCallbackInfo<v8::Value>& args) {
+  v8::Isolate* isolate = args.GetIsolate();
+
+  if (persistent.IsEmpty()) {
+    persistent.Reset(isolate, v8::Promise::Resolver::New(isolate));
+
+    uv_work_t* req = new uv_work_t;
+
+    uv_queue_work(uv_default_loop(), req, [](uv_work_t*) {}, Callback);
+  }
+
+  v8::Local<v8::Promise::Resolver> local =
+      v8::Local<v8::Promise::Resolver>::New(isolate, persistent);
+
+  args.GetReturnValue().Set(local->GetPromise());
+}
+
 void Initialize(v8::Local<v8::Object> exports) {
   NODE_SET_METHOD(exports, "runInCallbackScope", RunInCallbackScope);
+  NODE_SET_METHOD(exports, "testResolveAsync", TestResolveAsync);
 }
 
 }  // namespace

test/addons/callback-scope/test-resolve-async.js

@@ -0,0 +1,13 @@
+'use strict';
+
+const common = require('../../common');
+const assert = require('assert');
+const { testResolveAsync } = require(`./build/${common.buildType}/binding`);
+
+let called = false;
+testResolveAsync().then(common.mustCall(() => {
+  called = true;
+}));
+
+setTimeout(common.mustCall(() => { assert(called); }),
+           common.platformTimeout(20));