feat(router): add UrlSegment, RouteSegment, and Tree

modules/angular2/test/alt_router/tree_spec.ts

@@ -0,0 +1,43 @@
+import {
+  ComponentFixture,
+  AsyncTestCompleter,
+  TestComponentBuilder,
+  beforeEach,
+  ddescribe,
+  xdescribe,
+  describe,
+  el,
+  expect,
+  iit,
+  inject,
+  beforeEachProviders,
+  it,
+  xit
+} from 'angular2/testing_internal';
+
+import {Tree} from 'angular2/src/alt_router/segments';
+
+export function main() {
+  describe('tree', () => {
+    it("should return the root of the tree", () => {
+      let t = new Tree<any>([1, 2, 3]);
+      expect(t.root).toEqual(1);
+    });
+
+    it("should return the parent of a node", () => {
+      let t = new Tree<any>([1, 2, 3]);
+      expect(t.parent(1)).toEqual(null);
+      expect(t.parent(2)).toEqual(1);
+    });
+
+    it("should return the children of a node", () => {
+      let t = new Tree<any>([1, 2, 3]);
+      expect(t.children(1)).toEqual([2]);
+    });
+
+    it("should return the path to the root", () => {
+      let t = new Tree<any>([1, 2, 3]);
+      expect(t.pathToRoot(2)).toEqual([1, 2]);
+    });
+  });
+}