show attachments when expanding a non-threaded discussion

fixes #CNVS-1279

test plan:
 - create a discussion topic, reply to it, and create 5 side
 comments to the reply with at least one with an attachment
 - refresh the page and then click the arrow to show all the
 side comments
 - see that the side comment attachments are still visible

Change-Id: I47b7795f4e44caad3ce42bf31af21d73bf6dc6bf
Reviewed-on: https://gerrit.instructure.com/15797
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Zach Pendleton <zachp@instructure.com>
QA-Review: Marc LeGendre <marc@instructure.com>
Tested-by: Jon Willesen <jonw@instructure.com>

Author: Jon Willesen

app/coffeescripts/views/DiscussionTopic/EntryCollectionView.coffee

@@ -121,7 +121,7 @@ define [
       if @options.threaded
         @collection.add @collection.fullCollection.getPage 'next'
       else
-        @collection.reset @collection.fullCollection.toJSON()
+        @collection.reset @collection.fullCollection.toArray()
       @renderNextLink()
 
     filter: @::afterRender

spec/selenium/discussions_spec.rb

@@ -73,6 +73,24 @@
         @last_entry.find_element(:css, '.message').text.should == message
       end
 
+      it "should show attachments after showing hidden replies" do
+        @topic = @course.discussion_topics.create!(:title => 'test', :message => 'attachment test', :user => @user)
+        @entry = @topic.discussion_entries.create!(:user => @user, :message => 'blah')
+        @replies = []
+        5.times do
+          attachment = @course.attachments.create!(:context => @course, :filename => "text.txt", :user => @user, :uploaded_data => StringIO.new("testing"))
+          reply = @entry.discussion_subentries.create!(
+            :user => @user, :message => 'i haz attachments', :discussion_topic => @topic, :attachment => attachment)
+          @replies << reply
+        end
+        @topic.create_materialized_view
+        go_to_topic
+        ffj('.comment_attachments').count.should == 3
+        fj('.showMore').click
+        wait_for_ajaximations
+        ffj('.comment_attachments').count.should == @replies.count
+      end
+
       it "should show only 10 root replies per page"
       it "should paginate root entries"
       it "should show only three levels deep"

spec/selenium/helpers/discussions_common.rb

@@ -3,16 +3,20 @@
 shared_examples_for "discussions selenium tests" do
   it_should_behave_like "in-process server selenium tests"
 
+  def go_to_topic
+    get "/courses/#{@course.id}/discussion_topics/#{@topic.id}"
+    wait_for_ajax_requests
+  end
+
   def create_and_go_to_topic(title = 'new topic', discussion_type = 'side_comment', is_locked = false)
-    topic = @course.discussion_topics.create!(:title => title, :discussion_type => discussion_type)
+    @topic = @course.discussion_topics.create!(:title => title, :discussion_type => discussion_type)
     if is_locked
-      topic.workflow_state = 'locked'
-      topic.save!
-      topic.reload
+      @topic.workflow_state = 'locked'
+      @topic.save!
+      @topic.reload
     end
-    get "/courses/#{@course.id}/discussion_topics/#{topic.id}"
-    wait_for_ajax_requests
-    topic
+    go_to_topic
+    @topic
   end
 
   def create_discussion(discussion_name, discussion_type)