added tag alias unit test

app/models/tag.rb

@@ -1,7 +1,7 @@
 class Tag < ActiveRecord::Base
   attr_accessible :category
   after_save :update_category_cache
-  named_scope :by_pattern, lambda {|name| where(["name LIKE ? ESCAPE E'\\\\'", name.to_escaped_for_sql_like])}
+  scope :by_pattern, lambda {|name| where(["name LIKE ? ESCAPE E'\\\\'", name.to_escaped_for_sql_like])}
 
   class CategoryMapping
     Danbooru.config.reverse_tag_category_mapping.each do |value, category|

app/models/tag_alias.rb

@@ -1,8 +1,14 @@
 class TagAlias < ActiveRecord::Base
+  attr_accessor :updater_id, :updater_ip_addr
   after_save :update_posts
+  after_save :update_cache
+  validates_presence_of :updater_id, :updater_ip_addr
+  validates_uniqueness_of :antecedent_name
+  belongs_to :updater, :class_name => "User"
+  belongs_to :creator, :class_name => "User"
   
   def self.to_aliased(names)
-    alias_hash = Cache.get_multi(names, "ta") do |name|
+    alias_hash = Cache.get_multi(names.flatten, "ta") do |name|
       ta = TagAlias.find_by_antecedent_name(name)
       if ta
         ta.consequent_name
@@ -11,9 +17,22 @@ class TagAlias < ActiveRecord::Base
       end
     end
     
-    alias_hash.values
+    alias_hash.values.uniq
+  end
+  
+  def update_cache
+    Cache.put("ta:#{Cache.sanitize(antecedent_name)}", consequent_name, 24.hours)
   end
   
   def update_posts
+    Post.find_by_tags(antecedent_name).find_each do |post|
+      escaped_antecedent_name = Regexp.escape(antecedent_name)
+      fixed_tags = post.tag_string.sub(/\A#{escaped_antecedent_name} | #{escaped_antecedent_name} | #{escaped_antecedent_name}\Z/, " #{consequent_name} ").strip
+      post.update_attributes(
+        :tag_string => fixed_tags,
+        :updater_id => updater_id,
+        :updater_ip_addr => updater_ip_addr
+      )
+    end
   end
 end