8 files changed, 28 insertions, 29 deletions
diff --git a/actionmailer/lib/action_mailer.rb b/actionmailer/lib/action_mailer.rb
index a170eb7917..ade3fe39a2 100644
--- a/actionmailer/lib/action_mailer.rb
+++ b/actionmailer/lib/action_mailer.rb
@@ -24,7 +24,7 @@
 #++
 
 require "abstract_controller"
-require_relative "action_mailer/version"
+require "action_mailer/version"
 
 # Common Active Support usage in Action Mailer
 require "active_support"
diff --git a/actionmailer/lib/action_mailer/base.rb b/actionmailer/lib/action_mailer/base.rb
index 1c1e1a9a3b..eb8ae59533 100644
--- a/actionmailer/lib/action_mailer/base.rb
+++ b/actionmailer/lib/action_mailer/base.rb
@@ -1,13 +1,13 @@
 # frozen_string_literal: true
 
 require "mail"
-require_relative "collector"
+require "action_mailer/collector"
 require "active_support/core_ext/string/inflections"
 require "active_support/core_ext/hash/except"
 require "active_support/core_ext/module/anonymous"
 
-require_relative "log_subscriber"
-require_relative "rescuable"
+require "action_mailer/log_subscriber"
+require "action_mailer/rescuable"
 
 module ActionMailer
   # Action Mailer allows you to send email from your application using a mailer model and views.
diff --git a/actionmailer/lib/action_mailer/preview.rb b/actionmailer/lib/action_mailer/preview.rb
index 730ac89c94..0aea84fd2b 100644
--- a/actionmailer/lib/action_mailer/preview.rb
+++ b/actionmailer/lib/action_mailer/preview.rb
@@ -104,7 +104,7 @@ module ActionMailer
       private
         def load_previews
           if preview_path
-            Dir["#{preview_path}/**/*_preview.rb"].each { |file| require_dependency file }
+            Dir["#{preview_path}/**/*_preview.rb"].sort.each { |file| require_dependency file }
           end
         end
 
diff --git a/actionmailer/lib/rails/generators/mailer/templates/application_mailer.rb b/actionmailer/lib/rails/generators/mailer/templates/application_mailer.rb.tt
index 00fb9bd48f..00fb9bd48f 100644
--- a/actionmailer/lib/rails/generators/mailer/templates/application_mailer.rb
+++ b/actionmailer/lib/rails/generators/mailer/templates/application_mailer.rb.tt
diff --git a/actionmailer/lib/rails/generators/mailer/templates/mailer.rb b/actionmailer/lib/rails/generators/mailer/templates/mailer.rb.tt
index 348d314758..348d314758 100644
--- a/actionmailer/lib/rails/generators/mailer/templates/mailer.rb
+++ b/actionmailer/lib/rails/generators/mailer/templates/mailer.rb.tt
diff --git a/actionmailer/test/base_test.rb b/actionmailer/test/base_test.rb
index 0da969c349..977e0e201e 100644
--- a/actionmailer/test/base_test.rb
+++ b/actionmailer/test/base_test.rb
@@ -322,22 +322,21 @@ class BaseTest < ActiveSupport::TestCase
 
   test "implicit multipart with attachments creates nested parts" do
     email = BaseMailer.implicit_multipart(attachments: true)
-    assert_equal("application/pdf", email.parts[0].mime_type)
-    assert_equal("multipart/alternative", email.parts[1].mime_type)
-    assert_equal("text/plain", email.parts[1].parts[0].mime_type)
-    assert_equal("TEXT Implicit Multipart", email.parts[1].parts[0].body.encoded)
-    assert_equal("text/html", email.parts[1].parts[1].mime_type)
-    assert_equal("HTML Implicit Multipart", email.parts[1].parts[1].body.encoded)
+    assert_equal(%w[ application/pdf multipart/alternative ], email.parts.map(&:mime_type).sort)
+    multipart = email.parts.detect { |p| p.mime_type == "multipart/alternative" }
+    assert_equal("text/plain", multipart.parts[0].mime_type)
+    assert_equal("TEXT Implicit Multipart", multipart.parts[0].body.encoded)
+    assert_equal("text/html", multipart.parts[1].mime_type)
+    assert_equal("HTML Implicit Multipart", multipart.parts[1].body.encoded)
   end
 
   test "implicit multipart with attachments and sort order" do
     order = ["text/html", "text/plain"]
     with_default BaseMailer, parts_order: order do
       email = BaseMailer.implicit_multipart(attachments: true)
-      assert_equal("application/pdf", email.parts[0].mime_type)
-      assert_equal("multipart/alternative", email.parts[1].mime_type)
-      assert_equal("text/plain", email.parts[1].parts[1].mime_type)
-      assert_equal("text/html", email.parts[1].parts[0].mime_type)
+      assert_equal(%w[ application/pdf multipart/alternative ], email.parts.map(&:mime_type).sort)
+      multipart = email.parts.detect { |p| p.mime_type == "multipart/alternative" }
+      assert_equal(%w[ text/html text/plain ], multipart.parts.map(&:mime_type).sort)
     end
   end
 
@@ -427,12 +426,12 @@ class BaseTest < ActiveSupport::TestCase
 
   test "explicit multipart with attachments creates nested parts" do
     email = BaseMailer.explicit_multipart(attachments: true)
-    assert_equal("application/pdf", email.parts[0].mime_type)
-    assert_equal("multipart/alternative", email.parts[1].mime_type)
-    assert_equal("text/plain", email.parts[1].parts[0].mime_type)
-    assert_equal("TEXT Explicit Multipart", email.parts[1].parts[0].body.encoded)
-    assert_equal("text/html", email.parts[1].parts[1].mime_type)
-    assert_equal("HTML Explicit Multipart", email.parts[1].parts[1].body.encoded)
+    assert_equal(%w[ application/pdf multipart/alternative ], email.parts.map(&:mime_type).sort)
+    multipart = email.parts.detect { |p| p.mime_type == "multipart/alternative" }
+    assert_equal("text/plain", multipart.parts[0].mime_type)
+    assert_equal("TEXT Explicit Multipart", multipart.parts[0].body.encoded)
+    assert_equal("text/html", multipart.parts[1].mime_type)
+    assert_equal("HTML Explicit Multipart", multipart.parts[1].body.encoded)
   end
 
   test "explicit multipart with templates" do
diff --git a/actionmailer/test/caching_test.rb b/actionmailer/test/caching_test.rb
index e11e8d4676..ae4e7bf57e 100644
--- a/actionmailer/test/caching_test.rb
+++ b/actionmailer/test/caching_test.rb
@@ -198,7 +198,7 @@ end
 class CacheHelperOutputBufferTest < BaseCachingTest
   class MockController
     def read_fragment(name, options)
-      return false
+      false
     end
 
     def write_fragment(name, fragment, options)
@@ -214,9 +214,9 @@ class CacheHelperOutputBufferTest < BaseCachingTest
     output_buffer = ActionView::OutputBuffer.new
     controller = MockController.new
     cache_helper = Class.new do
-      def self.controller; end;
-      def self.output_buffer; end;
-      def self.output_buffer=; end;
+      def self.controller; end
+      def self.output_buffer; end
+      def self.output_buffer=; end
     end
     cache_helper.extend(ActionView::Helpers::CacheHelper)
 
@@ -235,9 +235,9 @@ class CacheHelperOutputBufferTest < BaseCachingTest
     output_buffer = ActiveSupport::SafeBuffer.new
     controller = MockController.new
     cache_helper = Class.new do
-      def self.controller; end;
-      def self.output_buffer; end;
-      def self.output_buffer=; end;
+      def self.controller; end
+      def self.output_buffer; end
+      def self.output_buffer=; end
     end
     cache_helper.extend(ActionView::Helpers::CacheHelper)
 
diff --git a/actionmailer/test/test_helper_test.rb b/actionmailer/test/test_helper_test.rb
index 5470d51599..3866097389 100644
--- a/actionmailer/test/test_helper_test.rb
+++ b/actionmailer/test/test_helper_test.rb
@@ -54,7 +54,7 @@ class TestHelperMailerTest < ActionMailer::TestCase
   end
 
   def test_encode
-    assert_equal "=?UTF-8?Q?This_is_=E3=81=82_string?=", encode("This is あ string")
+    assert_equal "This is あ string", Mail::Encodings.q_value_decode(encode("This is あ string"))
   end
 
   def test_read_fixture