Rails 6.1.5 ignores net-smtp LoadError

[JunichiIto]

Steps to reproduce

git clone git@github.com:JunichiIto/rails-6-1-mailer-sandbox.git
cd rails-6-1-mailer-sandbox
bin/setup
bin/rails test:system

Expected behavior

Fails to start server because of net-smtp LoadError

Actual behavior

Server can start up, then test fails with the error below:

2022-03-30 08:36:43 +0900 Rack app ("GET /" - (127.0.0.1)): #<NameError: uninitialized constant Mail::TestMailer

      delegate :deliveries, :deliveries=, to: Mail::TestMailer
                                                  ^^^^^^^^^^^^>
E

System configuration

Rails version:

• 6.1.5

Ruby version:

• 3.1.1

My investigation

The changes below were introduced since Rails 6.1.5:

• 13cdd7a
• 13cdd7a

However, the regexp should be /net\/stmp/ because error.message is "cannot load such file -- net/smtp":

Since net-smtp LoadError is ignored and mail gem is not loaded, the error "NameError: uninitialized constant Mail::TestMailer" is raised.

When I changed the regexp in my local box, the test fails like this:

You don't have net-smtp installed in your application. Please add it to your Gemfile and run bundle install
2022-03-30 08:47:59 +0900 Rack app ("GET /" - (127.0.0.1)): #<LoadError: cannot load such file -- net/smtp>
E

Error:
HomesTest#test_visiting_the_index:
LoadError: cannot load such file -- net/smtp
    app/mailers/application_mailer.rb:1:in `<main>'
    app/mailers/user_mailer.rb:1:in `<main>'
    app/controllers/home_controller.rb:3:in `index'


rails test test/system/homes_test.rb:4



Finished in 2.118014s, 0.4721 runs/s, 0.0000 assertions/s.
1 runs, 0 assertions, 0 failures, 1 errors, 0 skips

I guess this is the expected behavior.

[JunichiIto]

I confirmed this issue is already fixed, so I close.
8687a4f