refactoring tz to a variable rather than repeating it

activerecord/test/cases/attribute_methods_test.rb

@@ -133,13 +133,15 @@ def test_read_attributes_before_type_cast_on_datetime
   end
 
   def test_read_attributes_after_type_cast_on_datetime
-    in_time_zone "Pacific Time (US & Canada)" do
+    tz = "Pacific Time (US & Canada)"
+
+    in_time_zone tz do
       record = @target.new
 
       record.written_on = "2011-03-24"
       assert_equal "2011-03-24", record.written_on_before_type_cast
       assert_equal Time.zone.parse("2011-03-24"), record.written_on
-      assert_equal ActiveSupport::TimeZone["Pacific Time (US & Canada)"],
+      assert_equal ActiveSupport::TimeZone[tz],
         record.written_on.time_zone
 
       record.save