add AssetId test

Author: jakemac53

test/asset/id_test.dart

@@ -0,0 +1,71 @@
+// Copyright (c) 2016, 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.
+@TestOn('vm')
+import 'package:test/test.dart';
+
+import 'package:build/build.dart';
+
+// Forked from `barback/test/asset_id_test.dart`.
+main() {
+  group("constructor", () {
+    test("normalizes the path", () {
+      var id = new AssetId("app", r"path/././/to/drop/..//asset.txt");
+      expect(id.path, equals("path/to/asset.txt"));
+    });
+
+    test("normalizes backslashes to slashes in the path", () {
+      var id = new AssetId("app", r"path\to/asset.txt");
+      expect(id.path, equals("path/to/asset.txt"));
+    });
+  });
+
+  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);
+    });
+
+    test("normalizes the path", () {
+      var id = new AssetId.parse(r"app|path/././/to/drop/..//asset.txt");
+      expect(id.path, equals("path/to/asset.txt"));
+    });
+
+    test("normalizes backslashes to slashes in the path", () {
+      var id = new AssetId.parse(r"app|path\to/asset.txt");
+      expect(id.path, equals("path/to/asset.txt"));
+    });
+  });
+
+  test("equals another ID with the same package and path", () {
+    expect(new AssetId.parse("foo|asset.txt"), equals(
+           new AssetId.parse("foo|asset.txt")));
+
+    expect(new AssetId.parse("foo|asset.txt"), isNot(equals(
+        new AssetId.parse("bar|asset.txt"))));
+
+    expect(new AssetId.parse("foo|asset.txt"), isNot(equals(
+        new AssetId.parse("bar|other.txt"))));
+  });
+
+  test("identical assets are treated as the same in a Map/Set", () {
+    var id1 = new AssetId('a', 'web/a.txt');
+    var id2 = new AssetId('a', 'web/a.txt');
+
+    expect({id1: true}.containsKey(id2), isTrue);
+    expect(new Set<AssetId>.from([id1]), contains(id2));
+  });
+}