Updating barback test harness for angular transformers changes.

pkg/polymer/test/build/common.dart

 // 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.
 
 library polymer.test.build.common;
 
 import 'dart:async';
 
 import 'package:barback/barback.dart';
 import 'package:stack_trace/stack_trace.dart';
@@ skipping 48 matching lines @@
         print(Trace.format(trace));
       }
       fail('error running barback: $e');
     });
 
     resultSubscription = barback.results.listen((result) {
       expect(result.succeeded, !errorSeen, reason: "${result.errors}");
     });
 
     logSubscription = barback.log.listen((entry) {
+      // Ignore info messages.
+      if (entry.level == LogLevel.INFO) return;
       if (entry.level == LogLevel.ERROR) errorSeen = true;
       // We only check messages when an expectation is provided.
       if (messages == null) return;
 
       var msg = '${entry.level.name.toLowerCase()}: ${entry.message}';
       var span = entry.span;
       var spanInfo = span == null ? '' :
           ' (${span.sourceUrl} ${span.start.line} ${span.start.column})';
       expect(messagesSeen, lessThan(messages.length),
           reason: 'more messages than expected.\nMessage seen: $msg$spanInfo');
@@ skipping 23 matching lines @@
 
   Future check(String assetIdString, String content) {
     return this[assetIdString].then((value) {
       value = _removeTrailingWhitespace(value);
       content = _removeTrailingWhitespace(content);
       expect(value, content, reason: 'Final output of $assetIdString differs.');
     });
   }
 
   Future checkAll(Map<String, String> files) {
-    var futures = [];
-    files.forEach((k, v) {
-      futures.add(check(k, v));
-    });
-    return Future.wait(futures).then((_) {
+    return barback.results.first.then((_) {
+      if (files == null) return null;
+      var futures = [];
+      files.forEach((k, v) {
+        futures.add(check(k, v));
+      });
+      return Future.wait(futures);
+    }).then((_) {
       // We only check messages when an expectation is provided.
       if (messages == null) return;
       expect(messages.length, messagesSeen,
           reason: 'less messages than expected');
     });
   }
 }
 
 testPhases(String testName, List<List<Transformer>> phases,
     Map<String, String> inputFiles, Map<String, String> expectedFiles,
     [List<String> expectedMessages]) {
   test(testName, () {
     var helper = new TestHelper(phases, inputFiles, expectedMessages)..run();
     return helper.checkAll(expectedFiles).then((_) => helper.tearDown());
   });
 }
 
 const WEB_COMPONENTS_TAG =
     '<script src="packages/web_components/platform.js"></script>\n'
     '<script src="packages/web_components/dart_support.js"></script>\n';
 
 const INTEROP_TAG = '<script src="packages/browser/interop.js"></script>\n';
 const DART_JS_TAG = '<script src="packages/browser/dart.js"></script>';