Implement support for single stepping out of an async function.

runtime/observatory/tests/service/smart_next_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.
-// VMOptions=--error_on_bad_type --error_on_bad_override
-
-import 'package:observatory/models.dart' as M;
-import 'package:observatory/service_io.dart';
-import 'test_helper.dart';
-import 'dart:async';
-import 'dart:developer';
-import 'service_test_common.dart';
-
-const int LINE_A = 20;
-
-foo() async {}
-bar() {}
-
-doAsync(stop) async {
-  if (stop) debugger();
-  await foo(); // Line A.
-  bar(); // Line A + 1.
-  bar(); // Line A + 2.
-  await foo(); // Line A + 3.
-  await foo(); // Line A + 4.
-  bar(); // Line A + 5.
-  return null;
-}
-
-testMain() {
-  // With two runs of doAsync floating around, async step should only cause
-  // us to stop in the run we started in.
-  doAsync(false);
-  doAsync(true);
-}
-
-stepOverAwaitingResume(Isolate isolate) async {
-  Completer completer = new Completer();
-  await isolate.vm.getEventStream(VM.kDebugStream).then((stream) {
-    var subscription;
-    subscription = stream.listen((ServiceEvent event) {
-      if (event.kind == ServiceEvent.kResume) {
-        subscription.cancel();
-        completer.complete();
-      }
-    });
-  });
-  isolate.stepOver();
-  return completer.future;
-}
-
-smartNext(Isolate isolate) async {
-  if (M.isAtAsyncSuspension(isolate.pauseEvent)) {
-    print("next-async");
-    return asyncStepOver(isolate);
-  } else {
-    print("next-sync");
-    return stepOverAwaitingResume(isolate);
-  }
-}
-
-var tests = [
-  hasStoppedAtBreakpoint, stoppedAtLine(LINE_A), // foo()
-  smartNext, hasStoppedAtBreakpoint, stoppedAtLine(LINE_A), // await
-  smartNext, hasStoppedAtBreakpoint, stoppedAtLine(LINE_A + 1), // bar()
-  smartNext, hasStoppedAtBreakpoint, stoppedAtLine(LINE_A + 2), // bar()
-  smartNext, hasStoppedAtBreakpoint, stoppedAtLine(LINE_A + 3), // foo()
-  smartNext, hasStoppedAtBreakpoint, stoppedAtLine(LINE_A + 3), // await
-  smartNext, hasStoppedAtBreakpoint, stoppedAtLine(LINE_A + 4), // foo()
-  smartNext, hasStoppedAtBreakpoint, stoppedAtLine(LINE_A + 4), // await
-  smartNext, hasStoppedAtBreakpoint, stoppedAtLine(LINE_A + 5), // bar()
-  resumeIsolate,
-];
-
-main(args) => runIsolateTests(args, tests, testeeConcurrent: testMain);