Revamp trending projects query

This changes the query to use a COUNT nested in an INNER JOIN, instead
of a COUNT plus a GROUP BY. There are two reasons for this:

1. Using a COUNT in an INNER JOIN can be quite a bit faster.
2. The use of a GROUP BY means that method calls such as "any?"
   (and everything else that calls "count") operate on a Hash that
   counts the amount of notes on a per project basis, instead of just
   counting the total amount of projects.

The query has been moved into Project.trending as its logic is simple
enough. As a result of this testing the TrendingProjectsFinder class
simply involves testing if the right methods are called, removing the
need for setting up database records.

1 files changed, 2 insertions, 9 deletions

diff --git a/app/finders/trending_projects_finder.rb b/app/finders/trending_projects_finder.rb
index 9b710f0751f..81a12403801 100644
--- a/app/finders/trending_projects_finder.rb
+++ b/app/finders/trending_projects_finder.rb
@@ -1,13 +1,6 @@
 class TrendingProjectsFinder
-  def execute(current_user, start_date = nil)
-    start_date ||= Date.today - 1.month
-
-    projects = projects_for(current_user)
-
-    # Determine trending projects based on comments count
-    # for period of time - ex. month
-    projects.joins(:notes).where('notes.created_at >= ?', start_date).
-      group("projects.id").reorder("count(notes.id) DESC")
+  def execute(current_user, start_date = 1.month.ago)
+    projects_for(current_user).trending(start_date)
   end
 
   private