Async-step, first cut.

runtime/observatory/tests/service/async_scope_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=--compile_all --error_on_bad_type --error_on_bad_override
+
+import 'dart:async';
+import 'dart:developer';
+import 'package:observatory/service_io.dart';
+import 'package:unittest/unittest.dart';
+import 'test_helper.dart';
+
+foo() {}
+
+doAsync(param1) async {
+  var local1 = param1 + 1;
+  foo(); // Line 16
+  await null;
+}
+
+doAsyncStar(param2) async* {
+  var local2 = param2 + 1;
+  foo(); // Line 22
+  yield null;
+}
+
+testeeDo() {
+  debugger();
+
+  doAsync(1).then((_) {
+    doAsyncStar(1).listen((_) {});
+  });
+}
+
+
+checkAsyncVarDescriptors(Isolate isolate) async {
+  ServiceMap stack = await isolate.getStack();
+  expect(stack.type, equals('Stack'));
+  expect(stack['frames'].length, greaterThanOrEqualTo(1));
+  Frame frame = stack['frames'][0];
+  var vars = frame.variables.map((v) => v['name']).join(' ');
+  expect(vars, equals('param1 local1')); // no :async_op et al
+}
+
+
+checkAsyncStarVarDescriptors(Isolate isolate) async {
+  ServiceMap stack = await isolate.getStack();
+  expect(stack.type, equals('Stack'));
+  expect(stack['frames'].length, greaterThanOrEqualTo(1));
+  Frame frame = stack['frames'][0];
+  var vars = frame.variables.map((v) => v['name']).join(' ');
+  expect(vars, equals('param2 local2')); // no :async_op et al
+}
+
+
+var tests = [
+  hasStoppedAtBreakpoint, // debugger()
+  setBreakpointAtLine(16),
+  setBreakpointAtLine(22),
+  resumeIsolate,
+
+  hasStoppedAtBreakpoint,
+  stoppedAtLine(16),
+  checkAsyncVarDescriptors,
+  resumeIsolate,
+
+  hasStoppedAtBreakpoint,
+  stoppedAtLine(22),
+  checkAsyncStarVarDescriptors,
+  resumeIsolate,
+];
+
+main(args) => runIsolateTests(args, tests, testeeConcurrent: testeeDo);