Don't use skip, just don't run anything, we don't have skip in Ruby 1.8

activerecord/test/cases/associations/identity_map_test.rb

@@ -2,13 +2,10 @@ require "cases/helper"
 require 'models/author'
 require 'models/post'
 
+if ActiveRecord::IdentityMap.enabled?
 class InverseHasManyIdentityMapTest < ActiveRecord::TestCase
   fixtures :authors, :posts
 
-  def setup
-    skip unless ActiveRecord::IdentityMap.enabled?
-  end
-
   def test_parent_instance_should_be_shared_with_every_child_on_find
     m = Author.first
     is = m.posts
@@ -137,3 +134,4 @@ class InverseHasManyIdentityMapTest < ActiveRecord::TestCase
     assert_equal m.name, i.author.name, "Name of man should be the same after changes to replaced-child-owned instance"
   end
 end
+end

activerecord/test/cases/identity_map_test.rb

@@ -20,15 +20,12 @@ require "models/pirate"
 require "models/bird"
 require "models/parrot"
 
+if ActiveRecord::IdentityMap.enabled?
 class IdentityMapTest < ActiveRecord::TestCase
   fixtures :accounts, :companies, :developers, :projects, :topics,
     :developers_projects, :computers, :authors, :author_addresses,
     :posts, :tags, :taggings, :comments, :subscribers
 
-  def setup
-    skip unless ActiveRecord::IdentityMap.enabled?
-  end
-
   ##############################################################################
   # Basic tests checking if IM is functioning properly on basic find operations#
   ##############################################################################
@@ -402,3 +399,4 @@ class IdentityMapTest < ActiveRecord::TestCase
 #  end
 
 end
+end