Prevent the clearing of instance variables after each test request with Rails 7

Author: Jolyon Pawlyn

test/support/rails_7_patch.rb

@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+# HACK: to prevent the resetting of instance variables after each request in Rails 7
+# see https://github.com/rails/rails/pull/43735
+if Rails::VERSION::MAJOR >= 7
+  module ActionController
+    module Testing
+      module Functional
+        def clear_instance_variables_between_requests; end
+      end
+    end
+  end
+end

test/test_helper.rb

@@ -49,6 +49,7 @@ def silence_warnings
 
 require 'support/rails_app'
 
+require 'support/rails_7_patch'
 require 'support/ruby_2_6_rails_4_2_patch'
 
 # require "rails/test_help"