Added tests for docs.dart

tools/dom/docs/lib/docs.dart

Index: tools/dom/docs/lib/docs.dart
diff --git a/tools/dom/docs/lib/docs.dart b/tools/dom/docs/lib/docs.dart
index e4606ff259e787af36fb5302b6fb2fc9042cf990..7495fcdfb5a89596e701fea66c6bf5331404fc8f 100644
--- a/tools/dom/docs/lib/docs.dart
+++ b/tools/dom/docs/lib/docs.dart
@@ -1,3 +1,7 @@
+// Copyright (c) 2013, 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.
+
 /**
  * A library for extracting the documentation from the various HTML libraries
  * ([dart:html], [dart:svg], [dart:web_audio], [dart:indexed_db]) and saving
@@ -55,18 +59,18 @@ Future<bool> convert(Path libPath, Path jsonPath) {
   return analyze(paths, libPath, options: ['--preserve-comments'])
     .then((MirrorSystem mirrors) {
       var convertedJson = _generateJsonFromLibraries(mirrors);
-      return new Future.immediate(_exportJsonToFile(convertedJson, jsonPath));
+      return _exportJsonToFile(convertedJson, jsonPath);
     });
 }
 
-bool _exportJsonToFile(Map convertedJson, Path jsonPath) {
+Future<bool> _exportJsonToFile(Map convertedJson, Path jsonPath) {

[Bob Nystrom, 2013/03/28 14:18:40]

This method does both sync and async IO, which means it could both throw a
runtime exception or complete to one. We prefer having functions that return
futures to report all runtime errors through the future. The simple fix is to
wrap the sync IO in a future:

return Future.of(() {
  final jsonFile...
  ...
  return outputSream.done...
});

[Andrei Mouravski, 2013/03/28 17:01:14]

Done.

   final jsonFile = new File.fromPath(jsonPath);
   var writeJson = prettySerialize(convertedJson);
 
   var outputStream = jsonFile.openWrite();
   outputStream.writeln(writeJson);
-
-  return false;
+  outputStream.close();
+  return outputStream.done.then((_) => false);
 }
 
 Map _generateJsonFromLibraries(MirrorSystem mirrors) {