diff --git a/Gemfile b/Gemfile
index 64c859d2..1b657e7d 100644
--- a/Gemfile
+++ b/Gemfile
@@ -14,6 +14,7 @@ gem 'rake'
 gem 'rack', github: 'rack/rack'
 gem 'rack-test', '>= 0.6.2'
 gem "minitest", "~> 5.0"
+gem 'tool', '~> 0.2'
 
 if RUBY_ENGINE == 'jruby'
   gem 'nokogiri', '!= 1.5.0'
diff --git a/test/helper.rb b/test/helper.rb
index 49ce119a..775a6df8 100644
--- a/test/helper.rb
+++ b/test/helper.rb
@@ -5,6 +5,7 @@ RUBY_ENGINE = 'ruby' unless defined? RUBY_ENGINE
 
 require 'bundler'
 require 'bundler/setup'
+require 'tool/warning_filter'
 require 'rack'
 
 testdir = File.dirname(__FILE__)