Add tests for BuildGroup names

tools/gardening/test/test_client.dart

 // Copyright (c) 2017, 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.
 
 /// Compares the test log of a build step with previous builds.
 ///
 /// Use this to detect flakiness of failures, especially timeouts.
 
 import 'dart:async';
 import 'dart:io';
@@ skipping 15 matching lines @@
 
   String computePath(BuildUri buildUri) {
     return 'data/${buildUri.botName}/${buildUri.buildNumber}'
         '/${buildUri.stepName.replaceAll(' ', '_')}.log';
   }
 
   Future<String> readData(BuildUri buildUri) async {
     String path = computePath(buildUri);
     File file = new File.fromUri(Platform.script.resolve(path));
     if (!file.existsSync() && _client != null) {
-      await file.parent.create();
-      log('Pulling $buildUri from http');
+      await file.parent.create(recursive: true);
       BuildResult result = await _client.readResult(buildUri);
       if (result.buildNumber != null) {
         print('Writing test data to $file');
         String text = await cache.read(
             result.buildUri.logdogPath,
             () => throw new ArgumentError(
                 'Cache missing for ${result.buildUri.logdogPath}.'));
         await file.writeAsString(text);
       }
     }
     assert(file.existsSync(), "File $file not found.");
     log('Reading test data from $file');
     return file.readAsString();
   }
 
   @override
   Future<BuildResult> readResult(BuildUri buildUri) async {
     String text = await readData(buildUri);
     return parseTestStepResult(buildUri, text);
   }
 
   @override
   void close() {
     _client?.close();
   }
 
   @override
   int get mostRecentBuildNumber => -1;
 }