tests/web/native/event_loop_test.dart

// Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

import "dart:async";

import "package:expect/async_helper.dart";

import "native_testing.dart";

typedef void Callback0();

@Native("A")
class A {
  foo(Callback0 f) native;
}

makeA() native;

void setup() {
  JS('', r"""
(function(){
function A() {}
A.prototype.foo = function(f) { return f(); };
self.makeA = function() { return new A(); };
self.nativeConstructor(A);
})()""");
  applyTestExtensions(['A']);
}

main() {
  nativeTesting();
  setup();

  // Makes sure that we don't run the event-loop when we have a reentrant
  // call from JS to Dart code.
  // We start by setting up a microtask that should only run after main has
  // finished. We then pass a closure into JavaScript. That closure is
  // immediately invoked. Dart2js had a bug, that it would start the event-loop
  // at this moment (a JS->Dart transition), and execute the scheduled
  // microtask.

  var events = [];
  asyncStart();
  var a = makeA();
  new Future.microtask(() {
    events.add("scheduleMicrotask");
  }).whenComplete(asyncEnd);

  Expect.equals(
    499,
    a.foo(() {
      events.add("closure to foo");
      return 499;
    }),
  );

  events.add("after native call");
  Expect.listEquals(["closure to foo", "after native call"], events);
}