fix issue with using draper outside of controller/view context

fixes #926

however the current PR also drops support for rails < 6.0
open to discussion around this if there's any engagement on this PR.

draper.gemspec

@@ -16,10 +16,10 @@ Gem::Specification.new do |s|
 
   s.required_ruby_version = '>= 2.2.2'
 
-  s.add_dependency 'activesupport', '>= 5.0'
-  s.add_dependency 'actionpack', '>= 5.0'
+  s.add_dependency 'activesupport', '>= 6.0'
+  s.add_dependency 'actionpack', '>= 6.0'
   s.add_dependency 'request_store', '>= 1.0'
-  s.add_dependency 'activemodel', '>= 5.0'
+  s.add_dependency 'activemodel', '>= 6.0'
   s.add_dependency 'activemodel-serializers-xml', '>= 1.0'
   s.add_dependency 'ruby2_keywords'
 

lib/draper/view_context/build_strategy.rb

@@ -38,16 +38,12 @@ def call
         def controller
           Draper::ViewContext.controller ||= Draper.default_controller.new
           Draper::ViewContext.controller.tap do |controller|
-            controller.request ||= new_test_request controller if defined?(ActionController::TestRequest)
+            controller.request ||= new_test_request controller
           end
         end
 
         def new_test_request(controller)
-          is_above_rails_5_1 ? ActionController::TestRequest.create(controller) : ActionController::TestRequest.create
-        end
-
-        def is_above_rails_5_1
-          ActionController::TestRequest.method(:create).parameters.first == [:req, :controller_class]
+          ActionDispatch::TestRequest.create
         end
       end
     end

spec/draper/view_context/build_strategy_spec.rb

@@ -37,31 +37,14 @@ module Draper
 
         expect(controller.request).to be_nil
         strategy.call
-        expect(controller.request).to be_an ActionController::TestRequest
+        expect(controller.request).to be_an ActionDispatch::TestRequest
         expect(controller.params).to be_empty
 
         # sanity checks
         expect(controller.view_context.request).to be controller.request
         expect(controller.view_context.params).to be controller.params
       end
 
-      it "compatible with rails 5.1 change on ActionController::TestRequest.create method" do
-        ActionController::TestRequest.class_eval do
-          if ActionController::TestRequest.method(:create).parameters.first == []
-            def create controller_class
-              create
-            end
-          end
-        end
-        controller = Class.new(ActionController::Base).new
-        allow(ViewContext).to receive_messages controller: controller
-        strategy = ViewContext::BuildStrategy::Full.new
-
-        expect(controller.request).to be_nil
-        strategy.call
-        expect(controller.request).to be_an ActionController::TestRequest
-      end
-
       it "adds methods to the view context from the constructor block" do
         allow(ViewContext).to receive(:controller).and_return(fake_controller)
         strategy = ViewContext::BuildStrategy::Full.new do