Fix back-to-top backbone view

closes #6360

Changelog.md

@@ -10,7 +10,7 @@
 * Extract CommentService from CommentsController [#6307](https://github.com/diaspora/diaspora/pull/6307)
 * Extract user/profile discovery into the diaspora\_federation-rails gem [#6310](https://github.com/diaspora/diaspora/pull/6310)
 * Refactor PostPresenter [#6315](https://github.com/diaspora/diaspora/pull/6315)
-* Convert BackToTop to a backbone view [#6279](https://github.com/diaspora/diaspora/pull/6279)
+* Convert BackToTop to a backbone view [#6279](https://github.com/diaspora/diaspora/pull/6279) and [#6360](https://github.com/diaspora/diaspora/pull/6360)
 
 ## Bug fixes
 * Fix indentation and a link title on the default home page [#6212](https://github.com/diaspora/diaspora/pull/6212)

app/assets/javascripts/app/app.js

@@ -115,7 +115,7 @@ var app = {
       new app.views.AspectMembership({el: this});
     });
     app.sidebar = new app.views.Sidebar();
-    app.backToTop = new app.views.BackToTop();
+    app.backToTop = new app.views.BackToTop({el: $(document)});
   },
 
   /* mixpanel wrapper function */

spec/javascripts/app/views/back_to_top_view_spec.js

 describe("app.views.BackToTop", function() {
   beforeEach(function() {
     spec.loadFixture("aspects_index");
-    this.view = new app.views.BackToTop();
+    this.view = new app.views.BackToTop({el: $(document)});
+  });
+
+  describe("events hash", function() {
+    it("calls backToTop when clicking the back-to-top button", function() {
+      spyOn(this.view, "backToTop");
+      this.view.delegateEvents();
+      this.view.$("#back-to-top").click();
+      expect(this.view.backToTop).toHaveBeenCalled();
+    });
   });
 
   describe("backToTop", function() {