Don't require Transformer methods to return Futures.

pkg/barback/test/transformer_test.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 barback.test.transformer_test;
 
 import 'dart:async';
 
 import 'package:barback/barback.dart';
+import 'package:barback/src/utils.dart';
 import 'package:unittest/unittest.dart';
 
 import 'utils.dart';
 
 main() {
   initConfig();
 
   group("isPrimary", () {
     test("defaults to allowedExtensions", () {
       var transformer = new ExtensionTransformer(".txt .bin");
-      expect(transformer.isPrimary(new AssetId("pkg", "foo.txt")),
-          completion(isTrue));
+      expect(transformer.isPrimary(new AssetId("pkg", "foo.txt")), isTrue);
 
-      expect(transformer.isPrimary(new AssetId("pkg", "foo.bin")),
-          completion(isTrue));
+      expect(transformer.isPrimary(new AssetId("pkg", "foo.bin")), isTrue);
 
-      expect(transformer.isPrimary(new AssetId("pkg", "foo.nottxt")),
-          completion(isFalse));
+      expect(transformer.isPrimary(new AssetId("pkg", "foo.nottxt")), isFalse);
     });
 
     test("supports multi-level extensions with allowedExtensions", () {
       var transformer = new ExtensionTransformer(".dart.js");
-      expect(transformer.isPrimary(new AssetId("pkg", "foo.dart.js")),
-          completion(isTrue));
+      expect(transformer.isPrimary(new AssetId("pkg", "foo.dart.js")), isTrue);
 
-      expect(transformer.isPrimary(new AssetId("pkg", "foo.js")),
-          completion(isFalse));
-      expect(transformer.isPrimary(new AssetId("pkg", "foo.dart")),
-          completion(isFalse));
+      expect(transformer.isPrimary(new AssetId("pkg", "foo.js")), isFalse);
+
+      expect(transformer.isPrimary(new AssetId("pkg", "foo.dart")), isFalse);
     });
 
     test("throws an error for extensions without periods", () {
       expect(() => new ExtensionTransformer("dart"), throwsFormatException);
     });
 
     test("allows all files if allowedExtensions is not overridden", () {
       var transformer = new MockTransformer();
-      expect(transformer.isPrimary(new AssetId("pkg", "foo.txt")),
-          completion(isTrue));
+      expect(transformer.isPrimary(new AssetId("pkg", "foo.txt")), isTrue);
 
-      expect(transformer.isPrimary(new AssetId("pkg", "foo.bin")),
-          completion(isTrue));
+      expect(transformer.isPrimary(new AssetId("pkg", "foo.bin")), isTrue);
 
-      expect(transformer.isPrimary(new AssetId("pkg", "anything")),
-          completion(isTrue));
+      expect(transformer.isPrimary(new AssetId("pkg", "anything")), isTrue);
     });
   });
 }
 
 class MockTransformer extends Transformer {
   MockTransformer();
 
   Future apply(Transform transform) => new Future.value();
 }
 
 class ExtensionTransformer extends Transformer {
   final String allowedExtensions;
 
   ExtensionTransformer(this.allowedExtensions);
 
   Future apply(Transform transform) => new Future.value();
 }