First pass at build dependency graph for barback.

pkg/barback/test/asset_id_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.asset_id_test;
+
+import 'dart:async';
+
+import 'package:barback/barback.dart';
+import 'package:unittest/unittest.dart';
+
+import 'utils.dart';
+
+main() {
+  initConfig();
+  group("parse", () {
+    test("parses the package and path", () {
+      var id = new AssetId.parse("package|path/to/asset.txt");
+      expect(id.package, equals("package"));
+      expect(id.path, equals("path/to/asset.txt"));
+    });
+
+    test("throws if there are multiple '|'", () {
+      expect(() => new AssetId.parse("app|path|wtf"), throwsFormatException);
+    });
+
+    test("throws if the package name is empty '|'", () {
+      expect(() => new AssetId.parse("|asset.txt"), throwsFormatException);
+    });
+
+    test("throws if the path is empty '|'", () {
+      expect(() => new AssetId.parse("app|"), throwsFormatException);
+    });
+  });
+}