Expand the JSON reporter to enable a progress bar.

lib/src/backend/group.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 'metadata.dart';
 import 'operating_system.dart';
 import 'group_entry.dart';
 import 'test.dart';
 import 'test_platform.dart';
 
@@ skipping 15 matching lines @@
   /// A test to run before all tests in the group.
   ///
   /// This is `null` if no `setUpAll` callbacks were declared.
   final Test setUpAll;
 
   /// A test to run after all tests in the group.
   ///
   /// This is `null` if no `tearDown` callbacks were declared.
   final Test tearDownAll;
 
+  /// The number of tests (recursively) in this group.
+  int get testCount {
+    if (_testCount != null) return _testCount;
+    _testCount = entries.fold(0,
+        (count, entry) => count + (entry is Group ? entry.testCount : 1));
+    return _testCount;
+  }
+  int _testCount;
+
   Group(this.name, Iterable<GroupEntry> entries, {Metadata metadata,
           Test this.setUpAll, Test this.tearDownAll})
       : entries = new List<GroupEntry>.unmodifiable(entries),
         metadata = metadata == null ? new Metadata() : metadata;
 
   Group forPlatform(TestPlatform platform, {OperatingSystem os}) {
     if (!metadata.testOn.evaluate(platform, os: os)) return null;
     var newMetadata = metadata.forPlatform(platform, os: os);
     var filtered = _map((entry) => entry.forPlatform(platform, os: os));
     if (filtered.isEmpty && !entries.isEmpty) return null;
@@ skipping 11 matching lines @@
   /// Returns the entries of this group mapped using [callback].
   ///
   /// Any `null` values returned by [callback] will be removed.
   List<GroupEntry> _map(GroupEntry callback(GroupEntry entry)) {
     return entries
         .map((entry) => callback(entry))
         .where((entry) => entry != null)
         .toList();
   }
 }