Support Rails Engines?

[orionstudt]

I seem to have encountered an issue that makes it appear like Rails Engines are not supported here?

When you mount an engine it creates a method that points at an action dispatch routing proxy based on the name of your engine. But as soon as I register an observer for OpenapiFirst on my app within ActionDispatch::IntegrationTest, this method no longer exists.

As an example, my config/routes.rb file might be like:

# config/routes.rb
Rails.application.routes.draw do
  mount API::Engine, at: "/api", as: "api_engine"
end

And then in my test I can call the engine when I invoke rack-test like:

# engines/api/test/controllers/estimates_controller_test.rb
class API::EstimatesControllerTest < ApiIntegrationTest
  test "sample test" do
    get(api_engine.v1_estimates_path, params: ...)
  end
end

Now if I don't setup OpenapiFirst at all and set a breakpoint inside the test, I can check the values of app and api_engine:

[1] pry(#<API::EstimatesControllerTest>)> app
=> #<Wonder::Application>
[2] pry(#<API::EstimatesControllerTest>)> api_engine
=> #<ActionDispatch::Routing::RoutesProxy:0x000000017fb6d750

However if I setup OpenapiFirst in my test/test_helper.rb file like so:

# test/test_helper.rb
require_relative "../config/environment"
require "rails/test_help"

require "openapi_first"
OpenapiFirst::Test.setup do |test|
  test.register Rails.root.join("doc/api/openapi.yml").to_s
  test.report_coverage = false
end

module ActionDispatch
  class IntegrationTest
    include OpenapiFirst::Test::Methods[Wonder::Application]
  end
end

class ApiIntegrationTest < ActionDispatch::IntegrationTest
  # more setup ...
end

Then api_engine is no longer defined inside my test, and my tests fail with NameError.

[1] pry(#<API::EstimatesControllerTest>)> app
=> #<OpenapiFirst::Middlewares::ResponseValidation:0x0000000303a2d540
 @app=
  #<OpenapiFirst::Middlewares::RequestValidation:0x000000017e6948d8
   @app=Wonder::Application,
[2] pry(#<API::EstimatesControllerTest>)> api_engine
NameError: undefined local variable or method 'api_engine' for an instance of API::EstimatesControllerTest

[ahx]

Hi @orionstudt,

the most important thing that include OpenapiFirst::Test::Methods[Wonder::Application] does is to define an app method that looks something like this:

def app
  OpenapiFirst::Test.app(Wonder::Application)
end

When using rack-test, this app method is called to get the rack app under test.
It should not overwrite an "api_engine" method.
I am usually working with plain rack-test instead of ActionDispatch::IntegrationTest, so I don't know if just adding an "app" method is sufficient to make this work.

[orionstudt]

Hmm is that true? Because in your example you use ActionDispatch::IntegrationTest seen here:

https://github.com/ahx/openapi_first/blob/main/examples/rails_app/test/test_helper.rb#L23-L27

[ahx]

Yes, that example uses Rails. I have not used Engines though. If you can create a minimal failing example, that would be much appreciated.

[orionstudt]

@ahx Alright I got a minimal failing example up. You can see it in 3 example draft PRs I have opened, starting with this one: #412

[orionstudt]

It appears that there is some nuance in how Rails loads when there is an engine present that is breaking openapi_first.

[ahx]

Hey @orionstudt , thanks so much for these examples. Those will make it a lot easier to solve this issue. I will take a look shortly and will either merge some of the examples or add a (failing) unit test to test the root cause for this problem. Thanks for the feedback and work on this so far.

[orionstudt]

Hi @ahx ! Wondering if you've had a chance to look at this?

It's ok if not - I understand you likely have other things going on. I am open to making a contribution here if we won't be stepping on eachothers' toes and overlapping work, and if you can point me in any kinda of direction as to what I should be looking at.

I will likely start by digging into how your code is overriding app to get a better understanding of that and how engines might be affected by it.

[ahx]

Hey @orionstudt. Good news, I was able to fix example 1. See #412 (comment).

[orionstudt]

Hi @ahx, unfortunately that does not fix the issue. Responded on PR.

[ahx]

Hey @orionstudt I just wanted to let you know that I am starting to work on a fix as you described in https://github.com/ahx/openapi_first/pull/412/files#r2482535622 that keeps the methods existing on app intact.