diff --git a/activesupport/test/time_zone_test.rb b/activesupport/test/time_zone_test.rb
index b2bdea2934..2802ffd54a 100644
--- a/activesupport/test/time_zone_test.rb
+++ b/activesupport/test/time_zone_test.rb
@@ -75,13 +75,16 @@ class TimeZoneTest < Test::Unit::TestCase
 
   def test_unknown_timezones_delegation_to_tzinfo
     zone = ActiveSupport::TimeZone['America/Montevideo']
-    if defined?(TZInfo::TimeZone)
+    begin
+      require 'tzinfo/country'
+    rescue LoadError
+      # using vendored tzinfo which doesn't have tzinfo/country
+      assert_nil zone
+    else
       assert_equal ActiveSupport::TimeZone, zone.class
       assert_equal zone.object_id, ActiveSupport::TimeZone['America/Montevideo'].object_id
       assert_equal Time.utc(2010, 1, 31, 22), zone.utc_to_local(Time.utc(2010, 2)) # daylight saving offset -0200
       assert_equal Time.utc(2010, 3, 31, 21), zone.utc_to_local(Time.utc(2010, 4)) # standard offset -0300
-    else
-      assert_nil zone
     end
   end