[fix] Usage of HackathonConfig values in initializers

Need to use lambdas such that the real value is accurate whenever it’s called for

app/mailers/application_mailer.rb

@@ -1,4 +1,4 @@
 class ApplicationMailer < ActionMailer::Base
-  default from: HackathonConfig['email_from']
+  default from: -> { HackathonConfig['email_from'] }
   layout 'mailer'
 end

app/mailers/mailer.rb

@@ -2,7 +2,7 @@ class Mailer < ApplicationMailer
   include Roadie::Rails::Automatic
   add_template_helper(HackathonManagerHelper)
 
-  default from: HackathonConfig['email_from']
+  default from: -> { HackathonConfig['email_from'] }
 
   def bulk_message_email(message_id, user_id, message = nil)
     @message = message || Message.find_by_id(message_id)

config/initializers/devise.rb

@@ -13,7 +13,7 @@
   # Configure the e-mail address which will be shown in Devise::Mailer,
   # note that it will be overwritten if you use your own mailer class
   # with default "from" parameter.
-  config.mailer_sender = HackathonConfig['email_from']
+  config.mailer_sender = -> { HackathonConfig['email_from'] }
 
   # Configure the class responsible to send e-mails.
   # config.mailer = 'Devise::Mailer'

test/controllers/mailer_test.rb

@@ -47,4 +47,17 @@ class MailerTest < ActionMailer::TestCase
       assert_match %r{example.com\/rsvp}, email.encoded
     end
   end
+
+  context "with customized HackathonConfig" do
+    setup do
+      @user = create(:user, email: "test@example.com")
+      HackathonConfig['email_from'] = 'This is a test <test@custom.example.com>'
+    end
+
+    should "use customized email_from" do
+      email = Mailer.incomplete_reminder_email(@user.id).deliver_now
+
+      assert_equal ["test@custom.example.com"], email.from
+    end
+  end
 end