Improve calculation of PublicBody statistics columns

On PublicBody, we don't need to update info_requests_count
because that's already done with :counter_cache.  On the
other hand, info_requests_successful_count and
info_requests_not_held_count can't be updated easily with
counter_cache (since they need conditions to be attached).
Instead we update them in post_save and post_destroy,
as suggested here:

   http://blog.douglasfshearer.com/post/17495285851/custom-counter-cache-with-conditions

This also adds tests to ensure that the
after_(save|destroy) callbacks are called and that they
modify the counts correctly.

1 files changed, 3 insertions, 18 deletions

diff --git a/lib/tasks/stats.rake b/lib/tasks/stats.rake
index f7a3b07a5..1242575fe 100644
--- a/lib/tasks/stats.rake
+++ b/lib/tasks/stats.rake
@@ -94,25 +94,10 @@ namespace :stats do
   desc 'Update statistics in the public_bodies table'
   task :update_public_bodies_stats => :environment do
     PublicBody.all.each do |public_body|
-      puts "Finding statistics for #{public_body.name}"
-      [["info_requests_count=", nil],
-       ["info_requests_successful_count=", ['successful', 'partially_successful']],
-       ["info_requests_not_held_count=", ['not_held']]].each do |column, states|
-        puts "  Aggregating data for column #{column}"
-        where_clause = 'public_body_id = :pb'
-        parameters = {:pb => public_body.id}
-        if states
-          where_clause += " AND described_state in (:states)"
-          parameters[:states] = states
-        end
-        public_body.send(column,
-                         InfoRequest.where(where_clause,
-                                           parameters).count.to_s)
-      end
-      # Now looking for values of 'waiting_response_overdue' and
+      puts "Counting overdue requests for #{public_body.name}"
+      # Look for values of 'waiting_response_overdue' and
       # 'waiting_response_very_overdue' which aren't directly in the
-      # described_state column, and instead need to
-      puts "  Counting overdue requests"
+      # described_state column, and instead need to be calculated:
       overdue_count = 0
       very_overdue_count = 0
       InfoRequest.find_each(:conditions => {:public_body_id => public_body.id}) do |ir|