Add RunnerSuite.{on,is}Debugging properties.

lib/src/runner/browser/suite.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.
+
+library test.runner.browser.suite;
+
+import 'dart:async';
+
+import 'package:async/async.dart';
+
+import '../../backend/group.dart';
+import '../../backend/metadata.dart';
+import '../../backend/test.dart';
+import '../../backend/test_platform.dart';
+import '../../util/multi_channel.dart';
+import '../../util/remote_exception.dart';
+import '../../util/stack_trace_mapper.dart';
+import '../../util/stream_channel.dart';
+import '../../utils.dart';
+import '../environment.dart';
+import '../load_exception.dart';
+import '../runner_suite.dart';
+import 'iframe_test.dart';
+
+/// Loads a [RunnerSuite] for a browser.
+///
+/// [channel] should connect to the iframe containing the suite, which should
+/// eventually emit a message containing the suite's test information.
+/// [environment], [path], [platform], and [onClose] are passed to the
+/// [RunnerSuite]. If passed, [mapper] is used to reformat the test's stack
+/// traces.
+Future<RunnerSuite> loadBrowserSuite(StreamChannel channel,
+    Environment environment, String path, {StackTraceMapper mapper,
+    TestPlatform platform, AsyncFunction onClose}) async {
+  // The controller for the returned suite. This is set once we've loaded the
+  // information about the tests in the suite.
+  var controller;
+
+  // A timer that's reset whenever we receive a message from the browser.
+  // Because the browser stops running code when the user is actively debugging,
+  // this lets us detect whether they're debugging reasonably accurately.
+  //
+  // The duration should be short enough that the debugging console is open as
+  // soon as the user is done setting breakpoints, but long enough that a test
+  // doing a lot of synchronous work doesn't trigger a false positive.
+  var timer = new RestartableTimer(new Duration(seconds: 3), () {

[kevmoo, 2015/11/06 18:13:56]

const

+    controller.setDebugging(true);
+  })..cancel();

[kevmoo, 2015/11/06 18:13:56]

What the immediate cancel?

[nweiz, 2015/11/16 20:27:00]

Commented.

+
+  // Even though [channel] is probably a [MultiChannel] already, create a
+  // nested MultiChannel because the iframe will be using a channel wrapped
+  // within the host's channel.
+  var suiteChannel = new MultiChannel(channel.stream.map((message) {
+    // Whenever we get a message, no matter which child channel it's for, we the
+    // browser is still running code which means the using isn't debugging.
+    if (controller != null) {
+      timer.reset();
+      controller.setDebugging(false);
+    }
+
+    return message;
+  }), channel.sink);
+
+  var response = await _getResponse(suiteChannel.stream)
+      .timeout(new Duration(minutes: 1), onTimeout: () {
+    suiteChannel.sink.close();
+    throw new LoadException(
+        path,
+        "Timed out waiting for the test suite to connect.");
+  });
+
+  try {
+    _validateResponse(path, response);
+  } catch (_) {
+    suiteChannel.sink.close();
+    rethrow;
+  }
+
+  controller = new RunnerSuiteController(environment,
+      _deserializeGroup(suiteChannel, response["root"], mapper),
+      platform: platform, path: path,
+      onClose: () {
+    suiteChannel.sink.close();
+    timer.cancel();
+    return onClose == null ? null : onClose();
+  });
+
+  // Start the debugging timer counting down.
+  timer.reset();
+  return controller.suite;
+}
+
+/// Listens for responses from the iframe on [stream].
+///
+/// Returns the serialized representation of the the root group for the suite,
+/// or a response indicating that an error occurred.
+Future<Map> _getResponse(Stream stream) {

[kevmoo, 2015/11/06 18:13:56]

This would be a bit cleaner using async with await for

[nweiz, 2015/11/16 20:27:00]

I don't think that would allow it to be restructured at all, which means it
would just add tokens and overhead for no value.

+  var completer = new Completer();
+  stream.listen((response) {
+    if (response["type"] == "print") {
+      print(response["line"]);
+    } else if (response["type"] != "ping") {
+      completer.complete(response);
+    }
+  }, onDone: () {
+    if (!completer.isCompleted) completer.complete();
+  });
+
+  return completer.future;
+}
+
+/// Throws an error encoded in [response], if there is one.
+///
+/// [path] is used for the error's metadata.
+Future _validateResponse(String path, Map response) {

[kevmoo, 2015/11/06 18:13:56]

why not async?

You're being called from an async method – Future.error + Future.value seem
– too much

[nweiz, 2015/11/16 20:27:00]

Why would it be async? We shouldn't just use async in every function that
returns a future, we should use it in functions that actually get structural
benefits from it.

[kevmoo, 2015/11/16 23:21:23]

Consistency is nice. As is maintenance.

It's not clear why this method throws both sync and async errors.

[nweiz, 2015/11/16 23:48:14]

We consistently only use async where it provides benefit. That's also consistent
with how we use any other feature.
The only async error is the one that has to attach a specific stack trace.

+  if (response == null) {
+    throw new LoadException(
+        path, "Connection closed before test suite loaded.");
+  }
+
+  if (response["type"] == "loadException") {
+    throw new LoadException(path, response["message"]);
+  }
+
+  if (response["type"] == "error") {
+    var asyncError = RemoteException.deserialize(response["error"]);
+    return new Future.error(
+        new LoadException(path, asyncError.error),
+        asyncError.stackTrace);
+  }
+
+  return new Future.value();
+}
+
+/// Deserializes [group] into a concrete [Group] class.
+Group _deserializeGroup(MultiChannel suiteChannel, Map group,
+    [StackTraceMapper mapper]) {
+  var metadata = new Metadata.deserialize(group['metadata']);
+  return new Group(group['name'], group['entries'].map((entry) {
+    if (entry['type'] == 'group') {
+      return _deserializeGroup(suiteChannel, entry, mapper);
+    }
+
+    return _deserializeTest(suiteChannel, entry, mapper);
+  }),
+      metadata: metadata,
+      setUpAll: _deserializeTest(suiteChannel, group['setUpAll'], mapper),
+      tearDownAll:
+          _deserializeTest(suiteChannel, group['tearDownAll'], mapper));
+}
+
+/// Deserializes [test] into a concrete [Test] class.
+///
+/// Returns `null` if [test] is `null`.
+Test _deserializeTest(MultiChannel suiteChannel, Map test,
+    [StackTraceMapper mapper]) {
+  if (test == null) return null;
+
+  var metadata = new Metadata.deserialize(test['metadata']);
+  var testChannel = suiteChannel.virtualChannel(test['channel']);
+  return new IframeTest(test['name'], metadata, testChannel,
+      mapper: mapper);
+}