Require minitest for rails >= 4.1.0

Author: vanstee

lib/rspec/rails/adapters.rb

@@ -4,8 +4,14 @@
 module RSpec
   module Rails
     module Assertions
-      require 'test/unit/assertions'
-      include Test::Unit::Assertions
+      if ::Rails::VERSION::STRING >= '4.1.0'
+        gem 'minitest'
+        require 'minitest/assertions'
+        include Minitest::Assertions
+      else
+        require 'test/unit/assertions'
+        include Test::Unit::Assertions
+      end
     end
 
     class AssertionDelegator < Module