diff --git a/Gemfile b/Gemfile
index 92d39576..9a386356 100644
--- a/Gemfile
+++ b/Gemfile
@@ -21,8 +21,6 @@ if version == 'master'
     # Rails 5
     gem 'actionview'
   end
-  # Rails 5
-  gem 'rails-controller-testing', github: 'rails/rails-controller-testing'
 else
   gem_version = "~> #{version}.0"
   gem 'railties', gem_version
diff --git a/test/support/test_case.rb b/test/support/test_case.rb
index 66e8648d..c07b5bc0 100644
--- a/test/support/test_case.rb
+++ b/test/support/test_case.rb
@@ -2,4 +2,12 @@ ActionController::TestCase.class_eval do
   def setup
     @routes = TestHelper::Routes
   end
+
+  # For Rails5
+  # https://github.com/rails/rails/commit/ca83436d1b3b6cedd1eca2259f65661e69b01909#diff-b9bbf56e85d3fe1999f16317f2751e76L17
+  def assigns(key = nil)
+    assigns = {}.with_indifferent_access
+    @controller.view_assigns.each { |k, v| assigns.regular_writer(k, v) }
+    key.nil? ? assigns : assigns[key]
+  end
 end