Merge pull request rails#48989 from spickermann/sort-mailers-on-preview-page-alphabetically

Sort mailers on mailer preview page alphabetically

Author: rafaelfranca

actionmailer/CHANGELOG.md

@@ -1,3 +1,7 @@
+*   Mailers are listed in alphabetical order on the mailer preview page now.
+
+    *Martin Spickermann*
+
 *   Deprecate passing params to `assert_enqueued_email_with` via the `:args`
     kwarg. `assert_enqueued_email_with` now supports a `:params` kwarg, so use
     that to pass params:

actionmailer/lib/action_mailer/preview.rb

@@ -103,7 +103,7 @@ class << self
       # Returns all mailer preview classes.
       def all
         load_previews if descendants.empty?
-        descendants
+        descendants.sort_by { |mailer| mailer.name.titleize }
       end
 
       # Returns the mail object for the given email name. The registered preview

actionmailer/test/base_test.rb

@@ -1131,6 +1131,24 @@ def self.previewing_email(mail); end
   end
 end
 
+class PreviewTest < ActiveSupport::TestCase
+  class A < ActionMailer::Preview; end
+
+  module B
+    class A < ActionMailer::Preview; end
+    class C < ActionMailer::Preview; end
+  end
+
+  class C < ActionMailer::Preview; end
+
+  test "all() returns mailers in alphabetical order" do
+    ActionMailer::Preview.stub(:descendants, [C, A, B::C, B::A]) do
+      mailers = ActionMailer::Preview.all
+      assert_equal [A, B::A, B::C, C], mailers
+    end
+  end
+end
+
 class BasePreviewTest < ActiveSupport::TestCase
   class BaseMailerPreview < ActionMailer::Preview
     def welcome