Update trailing slash for search params.

backbone.js

@@ -1593,17 +1593,22 @@
       if (!History.started) return false;
       if (!options || options === true) options = {trigger: !!options};
 
-      var url = this.root + (fragment = this.getFragment(fragment || ''));
+      // Normalize the fragment.
+      fragment = this.getFragment(fragment || '');
+
+      // Don't include a trailing slash on the root.
+      var root = this.root;
+      if (fragment === '' || fragment.charAt(0) === '?') {
+        root = root.slice(0, -1) || '/';
+      }
+      var url = root + fragment;
 
       // Strip the hash and decode for matching.
       fragment = decodeURI(fragment.replace(pathStripper, ''));
 
       if (this.fragment === fragment) return;
       this.fragment = fragment;
 
-      // Don't include a trailing slash on the root.
-      if (fragment === '' && url !== '/') url = url.slice(0, -1);
-
       // If pushState is available, we use it to set the fragment as a real URL.
       if (this._hasPushState) {
         this.history[options.replace ? 'replaceState' : 'pushState']({}, document.title, url);

test/router.js

@@ -741,6 +741,21 @@
     Backbone.history.navigate('');
   });
 
+  test('#2656 - No trailing slash on root.', 1, function() {
+    Backbone.history.stop();
+    Backbone.history = _.extend(new Backbone.History, {
+      location: location,
+      history: {
+        pushState: function(state, title, url){
+          strictEqual(url, '/root?x=1');
+        }
+      }
+    });
+    location.replace('http://example.com/root/path');
+    Backbone.history.start({pushState: true, hashChange: false, root: 'root'});
+    Backbone.history.navigate('?x=1');
+  });
+
   test('#2765 - Fragment matching sans query/hash.', 2, function() {
     Backbone.history.stop();
     Backbone.history = _.extend(new Backbone.History, {