diff --git a/gemfiles/Gemfile.ruby1.9.3 b/gemfiles/Gemfile.ruby1.9.3
index f0b5f85d59c7af06ec8a168960ae77de3d7533aa..c1b9294d25efe696270499040febfa4eb9883063 100644
--- a/gemfiles/Gemfile.ruby1.9.3
+++ b/gemfiles/Gemfile.ruby1.9.3
@@ -13,7 +13,7 @@ group :development, :test do
 
   # i18n gem >=0.7.0 does not work with Ruby 1.9.2
   gem 'i18n', '0.6.1'
-  gem 'test-unit' # needed for Ruby >=2.2.0
+  gem 'test-unit' # install newer version with omit() method
 
   gem 'debugger'