Don't include routes helpers inside System test class:

- https://github.com/rails/rails/pull/36283 made a change to
  make SystemTest inherits from ActiveSupport::TestCase instead
  of ActionDispatch::IntegrationTest.

  With this change, the route helpers are now directly included inside
  the SystemTest class. This causes an edge case in case you have a
  routes whos name starts with `test_`, minitest will consider it as a
  test and will try to run it https://github.com/seattlerb/minitest/blob/ab39d35fb4e84eb866ed9c4ecb707cbf3889de42/lib/minitest/test.rb#L66

  This PR uses a proxy and deleted missing method to a dummy class
  that has all the route helpers.

2 files changed, 13 insertions, 6 deletions

diff --git a/actionpack/lib/action_dispatch/railtie.rb b/actionpack/lib/action_dispatch/railtie.rb
index 66f90980b9..2e09aed41d 100644
--- a/actionpack/lib/action_dispatch/railtie.rb
+++ b/actionpack/lib/action_dispatch/railtie.rb
@@ -54,11 +54,5 @@ module ActionDispatch
 
       ActionDispatch.test_app = app
     end
-
-    initializer "action_dispatch.system_tests" do |app|
-      ActiveSupport.on_load(:action_dispatch_system_test_case) do
-        include app.routes.url_helpers
-      end
-    end
   end
 end
diff --git a/actionpack/lib/action_dispatch/system_test_case.rb b/actionpack/lib/action_dispatch/system_test_case.rb
index 29864c0f8e..9772beb8aa 100644
--- a/actionpack/lib/action_dispatch/system_test_case.rb
+++ b/actionpack/lib/action_dispatch/system_test_case.rb
@@ -119,6 +119,11 @@ module ActionDispatch
     def initialize(*) # :nodoc:
       super
       self.class.driver.use
+      @proxy_route = if ActionDispatch.test_app
+        Class.new { include ActionDispatch.test_app.routes.url_helpers }.new
+      else
+        nil
+      end
     end
 
     def self.start_application # :nodoc:
@@ -163,6 +168,14 @@ module ActionDispatch
       default_url_options.merge(host: Capybara.app_host)
     end
 
+    def method_missing(method, *args, &block)
+      if @proxy_route.respond_to?(method)
+        @proxy_route.send(method, *args, &block)
+      else
+        super
+      end
+    end
+
     ActiveSupport.run_load_hooks(:action_dispatch_system_test_case, self)
   end