Do not disable submit button if comment is empty in mobile view

Fixes #5485

app/assets/javascripts/mobile/mobile_comments.js

@@ -30,13 +30,24 @@
         self.scrollToOffset(commentContainer);
       });
 
-      $(".stream").on("submit", ".new_comment", function(evt) {
+      $(".stream").on("submit", ".new_comment", this.submitComment);
+    },
+
+    submitComment: function(evt) {
       evt.preventDefault();
       var form = $(this);
+      var commentBox = form.find(".comment_box");
+      var commentText = $.trim(commentBox.val());
+      if (commentText) {
         $.post(form.attr("action")+"?format=mobile", form.serialize(), function(data) {
-          self.updateStream(form, data);
+          Diaspora.Mobile.Comments.updateStream(form, data);
         }, "html");
-      });
+        return true;
+      }
+      else {
+        commentBox.focus();
+        return false;
+      }
     },
 
     toggleComments: function(toggleReactionsLink) {

spec/controllers/jasmine_fixtures/comments_spec.rb

@@ -0,0 +1,20 @@
+#   Copyright (c) 2010-2011, Diaspora Inc.  This file is
+#   licensed under the Affero General Public License version 3 or later.  See
+#   the COPYRIGHT file.
+
+require "spec_helper"
+
+describe CommentsController, type: :controller do
+  describe "#comments" do
+    before do
+      sign_in :user, alice
+    end
+
+    context "jasmine fixtures" do
+      it "generates a jasmine fixture with the mobile comment box", fixture: true do
+        get :new, format: :mobile, post_id: 1
+        save_fixture(html_for("div"), "comments_mobile_commentbox")
+      end
+    end
+  end
+end

spec/javascripts/mobile/mobile_comments_spec.js

@@ -116,4 +116,26 @@ describe("Diaspora.Mobile.Comments", function(){
       expect(jQuery.ajax).not.toHaveBeenCalled();
     });
   });
+
+  describe("createComment", function () {
+    beforeEach(function() {
+      spec.loadFixture("aspects_index_mobile_post_with_comments");
+      var commentBoxHtml = spec.fixtureHtml("comments_mobile_commentbox");
+      var link = $(".stream .comment-action").first();
+      Diaspora.Mobile.Comments.showCommentBox(link);
+      jasmine.Ajax.requests.mostRecent().respondWith({
+        status: 200,
+        contentType: "text/html",
+        responseText: commentBoxHtml
+      });
+      $(".stream .new_comment").submit(Diaspora.Mobile.Comments.submitComment);
+    });
+
+    it("doesn't submit an empty comment", function() {
+      var form = $(".stream .new_comment").first();
+      spyOn(jQuery, "ajax");
+      form.submit();
+      expect(jQuery.ajax).not.toHaveBeenCalled();
+    });
+  });
 });