Remove implicit dependency on pathname

actionpack/lib/action_dispatch/routing/mapper.rb

@@ -1318,7 +1318,7 @@ def shallow?
 
         def draw(name)
           path = @draw_paths.find do |_path|
-            _path.join("#{name}.rb").file?
+            File.exists? "#{_path}/#{name}.rb"
           end
 
           unless path
@@ -1328,8 +1328,8 @@ def draw(name)
             raise ArgumentError, msg
           end
           
-          route_path = path.join("#{name}.rb")
-          instance_eval(route_path.read, route_path.to_s)
+          route_path = "#{path}/#{name}.rb"
+          instance_eval(File.read(route_path), route_path.to_s)
         end
 
         # match 'path' => 'controller#action'

actionpack/test/dispatch/routing_test.rb

@@ -2331,7 +2331,7 @@ def index
     end
   end
 
-  DRAW_PATH = Pathname.new(File.expand_path('../../fixtures/routes', __FILE__))
+  DRAW_PATH = File.expand_path('../../fixtures/routes', __FILE__)
 
   DefaultScopeRoutes = ActionDispatch::Routing::RouteSet.new.tap do |app|
     app.draw_paths << DRAW_PATH