announcements rss feed shows correct list of visible announcements

fixes CNVS-19529

test plan:
- in a course, create the following types of announcements:
  * a normal announcement that is visible
  * an announcement that is post_delayed for the future
  * an announcement that is closed for comments (create announcement, go
    to show page and close for comments in the cog menu)
  * an announcement that is deleted (create and the delete)
- view the announcement rss feed as a teacher and a student
- the teacher should see everything but the deleted discussion
- the student should just see the normal one and the closed for comments
  one

Change-Id: I46dd583c01cbd7817f3d599cb3816bf386cf3266
Reviewed-on: https://gerrit.instructure.com/51095
Tested-by: Jenkins
Reviewed-by: Mike Nomitch <mnomitch@instructure.com>
Reviewed-by: John Corrigan <jcorrigan@instructure.com>
QA-Review: Adam Stone <astone@instructure.com>
Product-Review: Simon Williams <simon@instructure.com>

app/controllers/announcements_controller.rb

@@ -49,7 +49,8 @@ class AnnouncementsController < ApplicationController
 
   def public_feed
     return unless get_feed_context
-    announcements = @context.announcements.active.order('posted_at DESC').limit(15).reject{|a| a.locked_for?(@current_user, :check_policies => true) }
+    announcements = @context.announcements.active.order('posted_at DESC').limit(15).
+      select{|a| a.visible_for?(@current_user) }
 
     respond_to do |format|
       format.atom {

app/controllers/discussion_topics_controller.rb

@@ -722,7 +722,8 @@ class DiscussionTopicsController < ApplicationController
       f.id = polymorphic_url([@context, :discussion_topics])
     end
     @entries = []
-    @entries.concat @context.discussion_topics.reject{|a| a.locked_for?(@current_user, :check_policies => true) }
+    @entries.concat @context.discussion_topics.
+      select{|dt| dt.visible_for?(@current_user) }
     @entries.concat @context.discussion_entries.active
     @entries = @entries.sort_by{|e| e.updated_at}
     @entries.each do |entry|

app/models/discussion_topic.rb

@@ -968,10 +968,9 @@ class DiscussionTopic < ActiveRecord::Base
   # Public: Determine if the given user can view this discussion topic.
   #
   # user - The user attempting to view the topic (default: nil).
-  # options - Options passed to the locked_for? call (default: {}).
   #
   # Returns a boolean.
-  def visible_for?(user = nil, options = {})
+  def visible_for?(user = nil)
     # user is the topic's author
     return true if user == self.user
 

lib/api/v1/discussion_topics.rb

@@ -41,7 +41,7 @@ module Api::V1::DiscussionTopics
   # Returns an array of hashes.
   def discussion_topics_api_json(topics, context, user, session, opts={})
     topics.inject([]) do |result, topic|
-      if topic.visible_for?(user, check_policies: true)
+      if topic.visible_for?(user)
         result << discussion_topic_api_json(topic, context, user, session, opts)
       end
 

spec/controllers/announcements_controller_spec.rb

@@ -23,11 +23,11 @@ describe AnnouncementsController do
     course_with_student(:active_all => true)
   end
 
-  def course_announcement
-    @announcement = @course.announcements.create!(
+  def course_announcement(opts = {})
+    @announcement = @course.announcements.create!({
       :title => "some announcement", 
       :message => "some message"
-    )
+    }.merge(opts))
   end
 
   describe "GET 'index'" do
@@ -73,13 +73,40 @@ describe AnnouncementsController do
     end
 
     it "shows the 15 most recent announcements" do
-      announcements = []
-      16.times { announcements << course_announcement.id }
-      announcements.shift # Drop first announcement so we have the 15 most recent
+      announcement_ids = []
+      16.times { announcement_ids << course_announcement.id }
+      announcement_ids.shift # Drop first announcement so we have the 15 most recent
+
       get 'public_feed', :format => 'atom', :feed_code => @enrollment.feed_code
+
       feed_entries = Atom::Feed.load_feed(response.body).entries
-      feed_entries.map!{ |e| e.id.gsub(/.*topic_/, "").to_i }
-      expect(feed_entries).to match_array(announcements)
+      feed_entry_ids = feed_entries.map{ |e| e.id.gsub(/.*topic_/, "").to_i }
+      expect(feed_entry_ids).to match_array(announcement_ids)
+    end
+
+    it "only shows announcements that are visible to the caller" do
+      normal_ann = @a # from the announcement_model in the before block
+      closed_for_comments_ann = course_announcement(locked: true)
+      post_delayed_ann = @course.announcements.build({
+        title: 'hi',
+        message: 'blah',
+        delayed_post_at: 1.day.from_now
+      })
+      post_delayed_ann.workflow_state = 'post_delayed'
+      post_delayed_ann.save!
+      deleted_ann = course_announcement
+      deleted_ann.destroy
+
+      expect(closed_for_comments_ann).to be_locked
+      expect(post_delayed_ann).to be_post_delayed
+      expect(deleted_ann).to be_deleted
+      visible_announcements = [normal_ann, closed_for_comments_ann]
+
+      get 'public_feed', :format => 'atom', :feed_code => @enrollment.feed_code
+
+      feed_entries = Atom::Feed.load_feed(response.body).entries
+      feed_entry_ids = feed_entries.map{ |e| e.id.gsub(/.*topic_/, "").to_i }
+      expect(feed_entry_ids).to match_array(visible_announcements.map(&:id))
     end
   end
 end