diff --git a/Gemfile b/Gemfile
index c3b4962de62ac0622fbe38c616433eebd8219d2a..874c34695152baa39236d10b6f76542b41077e5a 100644
--- a/Gemfile
+++ b/Gemfile
@@ -2,24 +2,24 @@ source 'https://rubygems.org'
 gemspec
 
 group :development do
-  gem 'minitest', '< 5.0'
+  gem 'test-unit' if RUBY_VERSION.start_with?('2.2')
   gem 'rake'
   gem 'redgreen', '~> 1.2'
   gem 'shoulda', '~> 3.5'
   gem 'rr', '~> 1.1'
   gem 'cucumber', '1.3.11'
-  gem 'redcarpet', '~> 3.1'
-  gem 'launchy', '~> 2.1.2'
+  gem 'redcarpet'
+  gem 'launchy', '~> 2.3'
 
   gem 'unicode_utils'
 
-  gem 'simplecov', '~>0.8', :require => false
+  gem 'simplecov', '~>0.9', :require => false
   gem 'rubinius-coverage', :platform => :rbx
   gem 'coveralls', :require => false
 end
 
 group :debug do
-  gem 'debugger', '~>1.6', :require => false, :platform => :mri
+  gem 'debugger', '~>1.6', :require => false, :platform => [:mri_19, :mri_20]
   gem 'rubinius-compiler', '~>2.0', :require => false, :platform => :rbx
   gem 'rubinius-debugger', '~>2.0', :require => false, :platform => :rbx
 end
diff --git a/features/support/env.rb b/features/support/env.rb
index 94c577fec29f363cf14d6c5481bd89e24d717700..cb04ca97751c31f13a16bc92fafd1eedfd6da68f 100644
--- a/features/support/env.rb
+++ b/features/support/env.rb
@@ -16,10 +16,6 @@ require 'test/unit'
 
 require 'jekyll/scholar'
 
-World do
-  include Test::Unit::Assertions
-end
-
 TEST_DIR = File.join('/', 'tmp', 'jekyll')
 
 def run_jekyll(options = {})