fix tests relying on implicit ordering

activerecord/test/cases/query_cache_test.rb

@@ -116,8 +116,9 @@ def test_cache_is_expired_by_habtm_update
   def test_cache_is_expired_by_habtm_delete
     ActiveRecord::Base.connection.expects(:clear_query_cache).times(2)
     ActiveRecord::Base.cache do
-      c = Category.find(:first)
-      p = Post.find(:first)
+      c = Category.find(1)
+      p = Post.find(1)
+      assert p.categories.any?
       p.categories.delete_all
     end
   end