use the database lower() function instead of ruby downcase

fixes CNVS-6974

test plan:
* create a user with Ĭńşŧřůćƭǜȑȩ in their name, enroll them in a course
* search for that user in the course roster, they should be found

Change-Id: Ia21d4d5163eec950cd45950123c1a273673a8c9a
Reviewed-on: https://gerrit.instructure.com/22470
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Cody Cutrer <cody@instructure.com>
Reviewed-by: Jacob Fugal <jacob@instructure.com>
QA-Review: Jeremy Putnam <jeremyp@instructure.com>
Product-Review: Brian Palmer <brianp@instructure.com>

app/models/communication_channel.rb

@@ -125,7 +125,7 @@ class CommunicationChannel < ActiveRecord::Base
     return if path.nil?
     return if retired?
     return unless user_id
-    conditions = ["LOWER(path)=? AND user_id=? AND path_type=? AND workflow_state IN('unconfirmed', 'active')", path.mb_chars.downcase, user_id, path_type]
+    conditions = ["LOWER(path)=LOWER(?) AND user_id=? AND path_type=? AND workflow_state IN('unconfirmed', 'active')", path, user_id, path_type]
     unless new_record?
       conditions.first << " AND id<>?"
       conditions << id
@@ -224,7 +224,7 @@ class CommunicationChannel < ActiveRecord::Base
     if %{mysql mysql2}.include?(connection_pool.spec.config[:adapter])
       where(:path => path)
     else
-      where("LOWER(communication_channels.path)=?", path.try(:downcase))
+      where("LOWER(communication_channels.path)=LOWER(?)", path)
     end
   }
 

app/models/enrollment.rb

@@ -875,13 +875,13 @@ class Enrollment < ActiveRecord::Base
     if Rails.version < '3.0'
       {
         :joins => { :user => :communication_channels },
-        :conditions => ["users.workflow_state='creation_pending' AND communication_channels.workflow_state='unconfirmed' AND path_type='email' AND LOWER(path)=?", email.downcase],
+        :conditions => ["users.workflow_state='creation_pending' AND communication_channels.workflow_state='unconfirmed' AND path_type='email' AND LOWER(path)=LOWER(?)", email],
         :select => 'enrollments.*',
         :readonly => false
       }
     else
       joins(:user => :communication_channels).
-          where("users.workflow_state='creation_pending' AND communication_channels.workflow_state='unconfirmed' AND path_type='email' AND LOWER(path)=?", email.downcase).
+          where("users.workflow_state='creation_pending' AND communication_channels.workflow_state='unconfirmed' AND path_type='email' AND LOWER(path)=LOWER(?)", email).
           select("enrollments.*").
           readonly(false)
     end

app/models/pseudonym.rb

@@ -113,7 +113,7 @@ class Pseudonym < ActiveRecord::Base
     if %w{mysql mysql2}.include?(connection_pool.spec.config[:adapter])
       where(:unique_id => unique_id)
     else
-      where("LOWER(#{quoted_table_name}.unique_id)=?", unique_id.mb_chars.downcase)
+      where("LOWER(#{quoted_table_name}.unique_id)=LOWER(?)", unique_id)
     end
   }
 

lib/user_search.rb

@@ -26,7 +26,7 @@ module UserSearch
 
   def self.like_string_for(search_term)
     pattern_type = (gist_search_enabled? ? :full : :right)
-    wildcard_pattern(search_term, :type => pattern_type)
+    wildcard_pattern(search_term, :type => pattern_type, :case_sensitive => false)
   end
 
   def self.scope_for(context, searcher, options={})
@@ -84,7 +84,7 @@ module UserSearch
   end
 
   def self.like_condition(value)
-    ActiveRecord::Base.like_condition(value)
+    ActiveRecord::Base.like_condition(value, 'lower(?)')
   end
 
   def self.wildcard_pattern(value, options)

spec/lib/user_search_spec.rb

@@ -1,9 +1,11 @@
+# encoding: utf-8
+
 require File.expand_path( '../spec_helper' , File.dirname(__FILE__))
 
 describe UserSearch do
 
   describe '.for_user_in_context' do
-    let(:search_names) { ['Rose Tyler', 'Martha Jones', 'Rosemary Giver', 'Martha Stewart', 'Tyler Pickett', 'Jon Stewart', 'Stewart Little'] }
+    let(:search_names) { ['Rose Tyler', 'Martha Jones', 'Rosemary Giver', 'Martha Stewart', 'Tyler Pickett', 'Jon Stewart', 'Stewart Little', 'Ĭńşŧřůćƭǜȑȩ Person'] }
     let(:course) { Course.create! }
     let(:users) { UserSearch.for_user_in_context('Stewart', course, user).to_a }
     let(:names) { users.map(&:name) }
@@ -26,6 +28,15 @@ describe UserSearch do
       describe 'with gist setting enabled' do
         before { Setting.set('user_search_with_gist', 'true') }
 
+        it "searches case-insensitively" do
+          UserSearch.for_user_in_context("steWArt", course, user).size.should == 3
+        end
+
+        it "uses postgres lower(), not ruby downcase()" do
+          # ruby 1.9 downcase doesn't handle the downcasing of many multi-byte characters correctly
+          UserSearch.for_user_in_context('Ĭńşŧřůćƭǜȑȩ', course, user).size.should == 1
+        end
+
         it 'returns an enumerable' do
           users.size.should == 3
         end
@@ -180,10 +191,6 @@ describe UserSearch do
   end
 
   describe '.like_string_for' do
-    it 'lowercases the term' do
-      UserSearch.like_string_for("MickyMouse").should =~ /mickymouse/
-    end
-
     it 'uses a prefix if gist is not configured' do
       Setting.set('user_search_with_gist', 'false')
       UserSearch.like_string_for("word").should == 'word%'