title: Capybara test failing with AJAX response
body: <p>I have the following Capybara test, which should click through and change the content of a comment.  The issue is that the content form is loaded into a modal that pops up upon clicking the edit button, and my modal isn't being rendered in the test.  (This functionality works in the app).  save_and_open_page opens a page containing just the json object.</p>
  
  <p>feature_spec.rb</p>
  
  <pre><code>require 'spec_helper'
  
  describe 'Edit comment' do
  
    let(:commented_post) { FactoryGirl.create(:post_with_comments) }
  
    describe "when current_user is the comment's author" do
      it 'should edit the comment content' do
        visit post_path(commented_post)
        within ("#comment-#{commented_post.comments.first.id}") do
          click_on "edit"
        end
        Capybara.default_wait_time = 15
        save_and_open_page
        fill_in 'comment_content', with: 'No, this is the best comment'
        click_on 'Edit Comment'
        expect(page).to have_content('No, this is the best comment')
      end
    end
  end
  </code></pre>
  
  <p>post.js</p>
  
  <pre><code>var EditForm = {
    init: function() {
      $('.get-edit-comment').on('ajax:success', this.showEditModal);
    },
  
    showEditModal: function(e, data) {
      e.preventDefault();
      $('.reveal-modal').html(data.edit_template);
      $('.reveal-modal').foundation('reveal', 'open');
    }
  }
  
  
  $(document).ready( function() {
    EditForm.init();
  });
  </code></pre>
  
  <p>comments_controller.rb</p>
  
  <pre><code>  def edit
      @post = Post.find_by_id(params[:post_id])
      @comment = Comment.find_by_id(params[:id])
      render :json =&gt; { 
        edit_template: render_to_string(:partial =&gt; 'comments/form', 
                                        :locals =&gt; {post: @post, comment: @comment})
        }
    end
  
    def update
      Comment.find_by_id(params[:id]).update(comment_params)
      redirect_to post_path(params[:post_id])
    end
  </code></pre>