fix(router): handle url fragments when no url segments present

modules/@angular/router/src/url_tree.ts

@@ -294,7 +294,7 @@ class UrlParser {
       this.capture('/');
     }
 
-    if (this.remaining === '' || this.remaining.startsWith('?')) {
+    if (this.remaining === '' || this.remaining.startsWith('?') || this.remaining.startsWith('#')) {
       return new UrlSegment([], {});
     } else {
       return new UrlSegment([], this.parseSegmentChildren());

modules/@angular/router/test/router.spec.ts

@@ -1237,9 +1237,8 @@ describe('Integration', () => {
                children: [{
                  path: 'link',
                  component: DummyLinkWithParentCmp,
-                  children: [
-                    {path: 'simple', component: SimpleCmp}, {path: '', component: BlankCmp}
-                  ]
+                 children:
+                     [{path: 'simple', component: SimpleCmp}, {path: '', component: BlankCmp}]
                }]
              }]);
 

modules/@angular/router/test/url_serializer.spec.ts

@@ -156,6 +156,11 @@ describe('url serializer', () => {
     expect(url.serialize(tree)).toEqual('/one#two');
   });
 
+  it('should parse fragment (root)', () => {
+    const tree = url.parse('/#one');
+    expectSegment(tree.root, '');
+    expect(url.serialize(tree)).toEqual('/#one');
+  });
 
   it('should parse empty fragment', () => {
     const tree = url.parse('/one#');