Start sketching out a buildAll() method.

pkg/barback/test/utils.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.utils;
 
 import 'dart:async';
 import 'dart:collection';
 import 'dart:io';
 
 import 'package:barback/barback.dart';
-import 'package:barback/src/asset_set.dart';
 import 'package:barback/src/cancelable_future.dart';
 import 'package:barback/src/utils.dart';
 import 'package:path/path.dart' as pathos;
 import 'package:scheduled_test/scheduled_test.dart';
 import 'package:stack_trace/stack_trace.dart';
 import 'package:unittest/compact_vm_config.dart';
 
 export 'transformer/bad.dart';
 export 'transformer/check_content.dart';
 export 'transformer/create_asset.dart';
@@ skipping 103 matching lines @@
 /// Removes [assets] from the current [PackageProvider].
 ///
 /// Each item in the list may either be an [AssetId] or a string that can be
 /// parsed as one. Unlike [removeSources], this is not automatically scheduled
 /// and will be run synchronously when called.
 void removeSourcesSync(Iterable assets) =>
     _barback.removeSources(_parseAssets(assets));
 
 /// Sets the transformers for [package] to [transformers].
 void updateTransformers(String package,
-    Iterable<Iterable<Transformers>> transformers) {
+    Iterable<Iterable<Transformer>> transformers) {
   schedule(() => _barback.updateTransformers(package, transformers),
       "updating transformers for $package");
 }
 
 /// Parse a list of strings or [AssetId]s into a list of [AssetId]s.
 List<AssetId> _parseAssets(Iterable assets) {
   return assets.map((asset) {
     if (asset is String) return new AssetId.parse(asset);
     return asset;
   }).toList();
@@ skipping 105 matching lines @@
   schedule(() {
     return _barback.getAssetById(id).then((asset) {
       fail("Should have thrown error but got $asset.");
     }).catchError((error) {
       expect(error, new isInstanceOf<AssetNotFoundException>());
       expect(error.id, equals(id));
     });
   }, "get asset $name");
 }
 
+/// Schedules an expectation that the graph will output all of the given
+/// assets, and no others.
+///
+/// [assets] is a list of strings that can be parsed to [AssetID]s.
+void expectAllAssets(Iterable<String> assets) {
+  var expected = assets.map((asset) => new AssetId.parse(asset));
+
+  schedule(() {
+    return _barback.getAllAssets().then((actualAssets) {
+      var actualIds = actualAssets.map((asset) => asset.id).toSet();
+
+      for (var id in expected) {
+        expect(actualIds, contains(id));
+        actualIds.remove(id);
+      }
+
+      expect(actualIds, isEmpty);
+    });
+  }, "get all assets, expecting ${expected.join(', ')}");
+}
+
+/// Schedules an expectation that [Barback.getAllAssets] will return a [Future]
+/// that completes to a error that matches [matcher].
+///
+/// If [match] is a [List], then it expects the completed error to be an
+/// [AggregateException] whose errors match each matcher in the list. Otherwise,
+/// [match] should be a single matcher that the error should match.
+void expectAllAssetsShouldFail(Matcher matcher) {
+  schedule(() {
+    expect(_barback.getAllAssets(), throwsA(matcher));
+  }, "get all assets should fail");
+}
+
 /// Schedules an expectation that a [getAssetById] call for the given asset
 /// won't terminate at this point in the schedule.
 void expectAssetDoesNotComplete(String name) {
   var id = new AssetId.parse(name);
 
   schedule(() {
     return _futureShouldNotCompleteUntil(
         _barback.getAssetById(id),
         pumpEventQueue(),
         "asset $id");
   }, "asset $id should not complete");
 }
 
+/// Returns a matcher for an [AggregateException] containing errors that match
+/// [matchers].
+Matcher isAggregateException(Iterable<Matcher> errors) {
+  // Match the aggregate error itself.
+  var matchers = [
+    new isInstanceOf<AggregateException>(),
+    transform((error) => error.errors, hasLength(errors.length),
+        'errors.length == ${errors.length}')
+  ];
+
+  // Make sure its contained errors match the matchers.
+  for (var error in errors) {
+    matchers.add(transform((error) => error.errors, contains(error),
+        error.toString()));
+  }
+
+  return allOf(matchers);
+}
+
 /// Returns a matcher for an [AssetNotFoundException] with the given [id].
 Matcher isAssetNotFoundException(String name) {
   var id = new AssetId.parse(name);
   return allOf(
       new isInstanceOf<AssetNotFoundException>(),
       predicate((error) => error.id == id, 'id == $name'));
 }
 
 /// Returns a matcher for an [AssetCollisionException] with the given [id].
 Matcher isAssetCollisionException(String name) {
@@ skipping 182 matching lines @@
 
   _MockAsset(this.id, this.contents);
 
   Future<String> readAsString({Encoding encoding}) =>
       new Future.value(contents);
 
   Stream<List<int>> read() => throw new UnimplementedError();
 
   String toString() => "MockAsset $id $contents";
 }