Fix isolate lifecycle handling in service library

runtime/observatory/test/isolate_lifecycle_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 'dart:isolate' as I;
+import 'dart:math';
+
+import 'package:observatory/service_io.dart';
+import 'package:unittest/unittest.dart';
+
+import 'test_helper.dart';
+
+final spawnCount = 4;
+final resumeCount = spawnCount ~/ 2;
+final isolates = [];
+
+void spawnEntry(int i) {
+}
+
+Future before() async {
+  // Spawn spawnCount long lived isolates.
+  for (var i = 0; i < spawnCount; i++) {
+    var isolate = await I.Isolate.spawn(spawnEntry, i);
+    isolates.add(isolate);
+  }
+  print('spawned all isolates');
+}
+
+Future during() {
+}
+
+var tests = [
+  (VM vm) async {
+    expect(vm.isolates.length, spawnCount + 1);
+  },
+  (VM vm) async {
+    // Load each isolate.
+    for (var isolate in vm.isolates) {
+      await isolate.load();
+    }
+  },
+  (VM vm) async {
+    var pausedCount = 0;
+    var runningCount = 0;
+    for (var isolate in vm.isolates) {
+      if (isolate.pauseEvent != null) {
+        pausedCount++;
+      } else {
+        runningCount++;
+      }
+    }
+    expect(pausedCount, spawnCount);
+    expect(runningCount, 1);
+  },
+  (VM vm) async {
+    var resumedReceived = 0;
+    var eventsDone = processServiceEvents(vm, (event, sub, completer) {
+      if (event.eventType.startsWith('IsolateShutdown')) {
+        resumedReceived++;
+        if (resumedReceived == resumeCount) {
+          sub.cancel();
+          completer.complete(null);
+        }
+      }
+    });
+    var resumesIssued = 0;
+    var isolateList = vm.isolates.toList();
+    for (var isolate in isolateList) {
+      if (isolate.name == 'root') {
+        continue;
+      }
+      try {
+        resumesIssued++;
+        await isolate.resume();
+      } catch(_) {}
+      if (resumesIssued == resumeCount) {
+        break;
+      }
+    }
+    return eventsDone;
+  },
+  (VM vm) async {
+    var pausedCount = 0;
+    var runningCount = 0;
+    for (var isolate in vm.isolates) {
+      if (isolate.pauseEvent != null) {
+        pausedCount++;
+      } else {
+        runningCount++;
+      }
+    }
+    expect(pausedCount, spawnCount - resumeCount);
+    expect(runningCount, 1);
+  },
+];
+
+main(args) async => runVMTests(args, tests,
+                               testeeBefore: before,
+                               testeeConcurrent: during,
+                               pause_on_exit: true);