expand the tmpdir to the realpath so tests on OS X pass

railties/test/isolation/abstract_unit.rb

@@ -30,7 +30,7 @@ def app_template_path
     end
 
     def tmp_path(*args)
-      @tmp_path ||= Dir.mktmpdir
+      @tmp_path ||= File.realpath(Dir.mktmpdir)
     end
 
     def app_path(*args)

railties/test/railties/generators_test.rb

@@ -13,7 +13,7 @@ def destination_root
     end
 
     def tmp_path(*args)
-      @tmp_path ||= Dir.mktmpdir
+      @tmp_path ||= File.realpath(Dir.mktmpdir)
       File.join(@tmp_path, *args)
     end