diff --git a/actionpack/lib/action_dispatch/testing/integration.rb b/actionpack/lib/action_dispatch/testing/integration.rb
index 8777666f9f8ac146ef442766c3105411a6831ed0..4f21403a904c1a3650b5556d03184ab3a1193fa4 100644
--- a/actionpack/lib/action_dispatch/testing/integration.rb
+++ b/actionpack/lib/action_dispatch/testing/integration.rb
@@ -336,8 +336,10 @@ def process(method, path, params: nil, headers: nil, env: nil, xhr: false, as: n
             end
             path = request_encoder.append_format_to location.path
             path = location.query ? "#{path}?#{location.query}" : path
-          else
-            path = request_encoder.append_format_to path
+          elsif !as.nil?
+            location = URI.parse(path)
+            path = request_encoder.append_format_to location.path
+            path = location.query ? "#{path}?#{location.query}" : path
           end
 
           hostname, port = host.split(':')
diff --git a/actionpack/test/controller/integration_test.rb b/actionpack/test/controller/integration_test.rb
index 34fb3b1003230729b0d1594917199e6cbd780782..3b89531e903210451893949f46bb16f7788e1334 100644
--- a/actionpack/test/controller/integration_test.rb
+++ b/actionpack/test/controller/integration_test.rb
@@ -1210,6 +1210,20 @@ def test_parsed_body_without_as_option
     end
   end
 
+  def test_get_parameters_with_as_option
+    with_routing do |routes|
+      routes.draw do
+        ActiveSupport::Deprecation.silence do
+          get ':action' => FooController
+        end
+      end
+
+      get '/foos_json?foo=heyo', as: :json
+
+      assert_equal({ 'foo' => 'heyo' }, response.parsed_body)
+    end
+  end
+
   private
     def post_to_foos(as:)
       with_routing do |routes|