make sure discussion subentry is deleted with parent

Change-Id: I5de4bb1a5527e6c7dc73205c1f6f8c329e74ad68
fixes: #6081
Reviewed-on: https://gerrit.instructure.com/6502
Tested-by: Hudson <hudson@instructure.com>
Reviewed-by: Cody Cutrer <cody@instructure.com>

app/models/discussion_entry.rb

@@ -157,6 +157,7 @@ class DiscussionEntry < ActiveRecord::Base
   
   alias_method :destroy!, :destroy
   def destroy
+    discussion_subentries.each &:destroy
     self.workflow_state = 'deleted'
     self.deleted_at = Time.now
     save!

db/migrate/20111026055002_delete_sub_entries_of_deleted_discussion_entries.rb

@@ -0,0 +1,10 @@
+class DeleteSubEntriesOfDeletedDiscussionEntries < ActiveRecord::Migration
+  def self.up
+    DiscussionEntry.find_each(:conditions => {:workflow_state => 'deleted'}) do |entry|
+      entry.discussion_subentries.each &:destroy
+    end
+  end
+
+  def self.down
+  end
+end

spec/models/discussion_entry_spec.rb

@@ -35,6 +35,21 @@ describe DiscussionEntry do
     sub_entry.save!
     sub_entry.parent_id.should eql(0)
   end
+
+  it "should be marked as deleted when parent is deleted" do
+    topic = course.discussion_topics.create!
+    entry = topic.discussion_entries.create!
+    
+    sub_entry = topic.discussion_entries.build
+    sub_entry.parent_id = entry.id
+    sub_entry.save!
+    
+    topic.discussion_entries.active.length.should == 2
+    entry.destroy
+    sub_entry.reload
+    sub_entry.should be_deleted
+    topic.discussion_entries.active.length.should == 0
+  end
   
   it "should only allow one level of nesting" do
     course