applies new string literal convention in actionmailer/test

The current code base is not uniform. After some discussion,
we have chosen to go with double quotes by default.

17 files changed, 257 insertions, 257 deletions

diff --git a/actionmailer/test/abstract_unit.rb b/actionmailer/test/abstract_unit.rb
index 8d740ac863..82f03f5cba 100644
--- a/actionmailer/test/abstract_unit.rb
+++ b/actionmailer/test/abstract_unit.rb
@@ -1,4 +1,4 @@
-require 'active_support/core_ext/kernel/reporting'
+require "active_support/core_ext/kernel/reporting"
 
 # These are the normal settings that will be set up by Railties
 # TODO: Have these tests support other combinations of these values
@@ -9,17 +9,17 @@ end
 
 module Rails
   def self.root
-    File.expand_path('../', File.dirname(__FILE__))
+    File.expand_path("../", File.dirname(__FILE__))
   end
 end
 
-require 'active_support/testing/autorun'
-require 'active_support/testing/method_call_assertions'
-require 'action_mailer'
-require 'action_mailer/test_case'
+require "active_support/testing/autorun"
+require "active_support/testing/method_call_assertions"
+require "action_mailer"
+require "action_mailer/test_case"
 
 # Emulate AV railtie
-require 'action_view'
+require "action_view"
 ActionMailer::Base.include(ActionView::Layouts)
 
 # Show backtraces for deprecated behavior for quicker cleanup.
@@ -28,15 +28,15 @@ ActiveSupport::Deprecation.debug = true
 # Disable available locale checks to avoid warnings running the test suite.
 I18n.enforce_available_locales = false
 
-FIXTURE_LOAD_PATH = File.expand_path('fixtures', File.dirname(__FILE__))
+FIXTURE_LOAD_PATH = File.expand_path("fixtures", File.dirname(__FILE__))
 ActionMailer::Base.view_paths = FIXTURE_LOAD_PATH
 
 # Skips the current run on Rubinius using Minitest::Assertions#skip
-def rubinius_skip(message = '')
-  skip message if RUBY_ENGINE == 'rbx'
+def rubinius_skip(message = "")
+  skip message if RUBY_ENGINE == "rbx"
 end
 # Skips the current run on JRuby using Minitest::Assertions#skip
-def jruby_skip(message = '')
+def jruby_skip(message = "")
   skip message if defined?(JRUBY_VERSION)
 end
 
diff --git a/actionmailer/test/assert_select_email_test.rb b/actionmailer/test/assert_select_email_test.rb
index cae2e20abd..820d7f34a7 100644
--- a/actionmailer/test/assert_select_email_test.rb
+++ b/actionmailer/test/assert_select_email_test.rb
@@ -1,4 +1,4 @@
-require 'abstract_unit'
+require "abstract_unit"
 
 class AssertSelectEmailTest < ActionMailer::TestCase
   class AssertSelectMailer < ActionMailer::Base
@@ -36,7 +36,7 @@ class AssertSelectEmailTest < ActionMailer::TestCase
   end
 
   def test_assert_select_email_multipart
-    AssertMultipartSelectMailer.test(html: "<div><p>foo</p><p>bar</p></div>", text: 'foo bar').deliver_now
+    AssertMultipartSelectMailer.test(html: "<div><p>foo</p><p>bar</p></div>", text: "foo bar").deliver_now
     assert_select_email do
       assert_select "div:root" do
         assert_select "p:first-child", "foo"
diff --git a/actionmailer/test/asset_host_test.rb b/actionmailer/test/asset_host_test.rb
index 10cfdcf693..c02ff53afa 100644
--- a/actionmailer/test/asset_host_test.rb
+++ b/actionmailer/test/asset_host_test.rb
@@ -1,11 +1,11 @@
-require 'abstract_unit'
-require 'action_controller'
+require "abstract_unit"
+require "action_controller"
 
 class AssetHostMailer < ActionMailer::Base
   def email_with_asset
-    mail to: 'test@localhost',
-      subject: 'testing email containing asset path while asset_host is set',
-      from: 'tester@example.com'
+    mail to: "test@localhost",
+      subject: "testing email containing asset path while asset_host is set",
+      from: "tester@example.com"
   end
 end
 
@@ -27,8 +27,8 @@ class AssetHostTest < ActionMailer::TestCase
 
   def test_asset_host_as_one_argument_proc
     AssetHostMailer.config.asset_host = Proc.new { |source|
-      if source.starts_with?('/images')
-        'http://images.example.com'
+      if source.starts_with?("/images")
+        "http://images.example.com"
       end
     }
     mail = AssetHostMailer.email_with_asset
diff --git a/actionmailer/test/base_test.rb b/actionmailer/test/base_test.rb
index 50f2c71737..cc7b90d7a4 100644
--- a/actionmailer/test/base_test.rb
+++ b/actionmailer/test/base_test.rb
@@ -1,12 +1,12 @@
-require 'abstract_unit'
-require 'set'
+require "abstract_unit"
+require "set"
 
-require 'action_dispatch'
-require 'active_support/time'
+require "action_dispatch"
+require "active_support/time"
 
-require 'mailers/base_mailer'
-require 'mailers/proc_mailer'
-require 'mailers/asset_mailer'
+require "mailers/base_mailer"
+require "mailers/proc_mailer"
+require "mailers/asset_mailer"
 
 class BaseTest < ActiveSupport::TestCase
   include Rails::Dom::Testing::Assertions::DomAssertions
@@ -32,33 +32,33 @@ class BaseTest < ActiveSupport::TestCase
   # Basic mail usage without block
   test "mail() should set the headers of the mail message" do
     email = BaseMailer.welcome
-    assert_equal(['system@test.lindsaar.net'],    email.to)
-    assert_equal(['jose@test.plataformatec.com'], email.from)
-    assert_equal('The first email on new API!',   email.subject)
+    assert_equal(["system@test.lindsaar.net"],    email.to)
+    assert_equal(["jose@test.plataformatec.com"], email.from)
+    assert_equal("The first email on new API!",   email.subject)
   end
 
   test "mail() with from overwrites the class level default" do
-    email = BaseMailer.welcome(from: 'someone@example.com',
-                               to:   'another@example.org')
-    assert_equal(['someone@example.com'], email.from)
-    assert_equal(['another@example.org'], email.to)
+    email = BaseMailer.welcome(from: "someone@example.com",
+                               to:   "another@example.org")
+    assert_equal(["someone@example.com"], email.from)
+    assert_equal(["another@example.org"], email.to)
   end
 
   test "mail() with bcc, cc, content_type, charset, mime_version, reply_to and date" do
     time  = Time.now.beginning_of_day.to_datetime
-    email = BaseMailer.welcome(bcc: 'bcc@test.lindsaar.net',
-                               cc: 'cc@test.lindsaar.net',
-                               content_type: 'multipart/mixed',
-                               charset: 'iso-8559-1',
-                               mime_version: '2.0',
-                               reply_to: 'reply-to@test.lindsaar.net',
+    email = BaseMailer.welcome(bcc: "bcc@test.lindsaar.net",
+                               cc: "cc@test.lindsaar.net",
+                               content_type: "multipart/mixed",
+                               charset: "iso-8559-1",
+                               mime_version: "2.0",
+                               reply_to: "reply-to@test.lindsaar.net",
                                date: time)
-    assert_equal(['bcc@test.lindsaar.net'],             email.bcc)
-    assert_equal(['cc@test.lindsaar.net'],              email.cc)
-    assert_equal('multipart/mixed; charset=iso-8559-1', email.content_type)
-    assert_equal('iso-8559-1',                          email.charset)
-    assert_equal('2.0',                                 email.mime_version)
-    assert_equal(['reply-to@test.lindsaar.net'],        email.reply_to)
+    assert_equal(["bcc@test.lindsaar.net"],             email.bcc)
+    assert_equal(["cc@test.lindsaar.net"],              email.cc)
+    assert_equal("multipart/mixed; charset=iso-8559-1", email.content_type)
+    assert_equal("iso-8559-1",                          email.charset)
+    assert_equal("2.0",                                 email.mime_version)
+    assert_equal(["reply-to@test.lindsaar.net"],        email.reply_to)
     assert_equal(time,                                  email.date)
   end
 
@@ -75,63 +75,63 @@ class BaseTest < ActiveSupport::TestCase
 
   test "should set template content type if mail has only one part" do
     mail = BaseMailer.html_only
-    assert_equal('text/html', mail.mime_type)
+    assert_equal("text/html", mail.mime_type)
     mail = BaseMailer.plain_text_only
-    assert_equal('text/plain', mail.mime_type)
+    assert_equal("text/plain", mail.mime_type)
   end
 
   # Custom headers
   test "custom headers" do
     email = BaseMailer.welcome
-    assert_equal("Not SPAM", email['X-SPAM'].decoded)
+    assert_equal("Not SPAM", email["X-SPAM"].decoded)
   end
 
   test "can pass random headers in as a hash to mail" do
-    hash = {'X-Special-Domain-Specific-Header' => "SecretValue",
-            'In-Reply-To' => '1234@mikel.me.com' }
+    hash = {"X-Special-Domain-Specific-Header" => "SecretValue",
+            "In-Reply-To" => "1234@mikel.me.com" }
     mail = BaseMailer.welcome(hash)
-    assert_equal('SecretValue', mail['X-Special-Domain-Specific-Header'].decoded)
-    assert_equal('1234@mikel.me.com', mail['In-Reply-To'].decoded)
+    assert_equal("SecretValue", mail["X-Special-Domain-Specific-Header"].decoded)
+    assert_equal("1234@mikel.me.com", mail["In-Reply-To"].decoded)
   end
 
   test "can pass random headers in as a hash to headers" do
-    hash = {'X-Special-Domain-Specific-Header' => "SecretValue",
-            'In-Reply-To' => '1234@mikel.me.com' }
+    hash = {"X-Special-Domain-Specific-Header" => "SecretValue",
+            "In-Reply-To" => "1234@mikel.me.com" }
     mail = BaseMailer.welcome_with_headers(hash)
-    assert_equal('SecretValue', mail['X-Special-Domain-Specific-Header'].decoded)
-    assert_equal('1234@mikel.me.com', mail['In-Reply-To'].decoded)
+    assert_equal("SecretValue", mail["X-Special-Domain-Specific-Header"].decoded)
+    assert_equal("1234@mikel.me.com", mail["In-Reply-To"].decoded)
   end
 
   # Attachments
   test "attachment with content" do
     email = BaseMailer.attachment_with_content
     assert_equal(1, email.attachments.length)
-    assert_equal('invoice.pdf', email.attachments[0].filename)
-    assert_equal('This is test File content', email.attachments['invoice.pdf'].decoded)
+    assert_equal("invoice.pdf", email.attachments[0].filename)
+    assert_equal("This is test File content", email.attachments["invoice.pdf"].decoded)
   end
 
   test "attachment gets content type from filename" do
     email = BaseMailer.attachment_with_content
-    assert_equal('invoice.pdf', email.attachments[0].filename)
-    assert_equal('application/pdf', email.attachments[0].mime_type)
+    assert_equal("invoice.pdf", email.attachments[0].filename)
+    assert_equal("application/pdf", email.attachments[0].mime_type)
   end
 
   test "attachment with hash" do
     email = BaseMailer.attachment_with_hash
     assert_equal(1, email.attachments.length)
-    assert_equal('invoice.jpg', email.attachments[0].filename)
+    assert_equal("invoice.jpg", email.attachments[0].filename)
     expected = "\312\213\254\232)b"
     expected.force_encoding(Encoding::BINARY)
-    assert_equal expected, email.attachments['invoice.jpg'].decoded
+    assert_equal expected, email.attachments["invoice.jpg"].decoded
   end
 
   test "attachment with hash using default mail encoding" do
     email = BaseMailer.attachment_with_hash_default_encoding
     assert_equal(1, email.attachments.length)
-    assert_equal('invoice.jpg', email.attachments[0].filename)
+    assert_equal("invoice.jpg", email.attachments[0].filename)
     expected = "\312\213\254\232)b"
     expected.force_encoding(Encoding::BINARY)
-    assert_equal expected, email.attachments['invoice.jpg'].decoded
+    assert_equal expected, email.attachments["invoice.jpg"].decoded
   end
 
   test "sets mime type to multipart/mixed when attachment is included" do
@@ -215,24 +215,24 @@ class BaseTest < ActiveSupport::TestCase
       email = BaseMailer.welcome(subject: nil)
       assert_equal "Welcome", email.subject
 
-      with_translation 'en', base_mailer: {welcome: {subject: "New Subject!"}} do
+      with_translation "en", base_mailer: {welcome: {subject: "New Subject!"}} do
         email = BaseMailer.welcome(subject: nil)
         assert_equal "New Subject!", email.subject
       end
     end
   end
 
-  test 'default subject can have interpolations' do
-    with_translation 'en', base_mailer: {with_subject_interpolations: {subject: 'Will the real %{rapper_or_impersonator} please stand up?'}} do
+  test "default subject can have interpolations" do
+    with_translation "en", base_mailer: {with_subject_interpolations: {subject: "Will the real %{rapper_or_impersonator} please stand up?"}} do
       email = BaseMailer.with_subject_interpolations
-      assert_equal 'Will the real Slim Shady please stand up?', email.subject
+      assert_equal "Will the real Slim Shady please stand up?", email.subject
     end
   end
 
   test "translations are scoped properly" do
-    with_translation 'en', base_mailer: {email_with_translations: {greet_user: "Hello %{name}!"}} do
+    with_translation "en", base_mailer: {email_with_translations: {greet_user: "Hello %{name}!"}} do
       email = BaseMailer.email_with_translations
-      assert_equal 'Hello lifo!', email.body.encoded
+      assert_equal "Hello lifo!", email.body.encoded
     end
   end
 
@@ -240,7 +240,7 @@ class BaseTest < ActiveSupport::TestCase
     class LateAttachmentMailer < ActionMailer::Base
       def welcome
         mail body: "yay", from: "welcome@example.com", to: "to@example.com"
-        attachments['invoice.pdf'] = 'This is test File content'
+        attachments["invoice.pdf"] = "This is test File content"
       end
     end
 
@@ -252,7 +252,7 @@ class BaseTest < ActiveSupport::TestCase
     class LateInlineAttachmentMailer < ActionMailer::Base
       def welcome
         mail body: "yay", from: "welcome@example.com", to: "to@example.com"
-        attachments.inline['invoice.pdf'] = 'This is test File content'
+        attachments.inline["invoice.pdf"] = "This is test File content"
       end
     end
 
@@ -271,13 +271,13 @@ class BaseTest < ActiveSupport::TestCase
     assert_nothing_raised { mail.message }
 
     assert_equal ["image/jpeg; filename=controller_attachments.jpg",
-                  "image/jpeg; filename=attachments.jpg"], mail.attachments.inline.map {|a| a['Content-Type'].to_s }
+                  "image/jpeg; filename=attachments.jpg"], mail.attachments.inline.map {|a| a["Content-Type"].to_s }
   end
 
   test "accessing attachments works after mail was called" do
     class LateAttachmentAccessorMailer < ActionMailer::Base
       def welcome
-        attachments['invoice.pdf'] = 'This is test File content'
+        attachments["invoice.pdf"] = "This is test File content"
         mail body: "yay", from: "welcome@example.com", to: "to@example.com"
 
         unless attachments.map(&:filename) == ["invoice.pdf"]
@@ -366,7 +366,7 @@ class BaseTest < ActiveSupport::TestCase
       I18n.backend = fallback_backend.new
       I18n.fallbacks[:"de-AT"] = [:de]
 
-      swap I18n, locale: 'de-AT' do
+      swap I18n, locale: "de-AT" do
         email = BaseMailer.implicit_with_locale
         assert_equal(2, email.parts.size)
         assert_equal("multipart/alternative", email.mime_type)
@@ -449,7 +449,7 @@ class BaseTest < ActiveSupport::TestCase
     assert_equal("Format with any!", email.parts[1].body.encoded)
   end
 
-  test 'explicit without specifying format with format.any' do
+  test "explicit without specifying format with format.any" do
     error = assert_raises(ArgumentError) do
       BaseMailer.explicit_without_specifying_format_with_any.parts
     end
@@ -508,13 +508,13 @@ class BaseTest < ActiveSupport::TestCase
   test "calling just the action should return the generated mail object" do
     email = BaseMailer.welcome
     assert_equal(0, BaseMailer.deliveries.length)
-    assert_equal('The first email on new API!', email.subject)
+    assert_equal("The first email on new API!", email.subject)
   end
 
   test "calling deliver on the action should deliver the mail object" do
     assert_called(BaseMailer, :deliver_mail) do
       mail = BaseMailer.welcome.deliver_now
-      assert_equal 'The first email on new API!', mail.subject
+      assert_equal "The first email on new API!", mail.subject
     end
   end
 
@@ -534,35 +534,35 @@ class BaseTest < ActiveSupport::TestCase
 
   # Rendering
   test "you can specify a different template for implicit render" do
-    mail = BaseMailer.implicit_different_template('implicit_multipart').deliver_now
+    mail = BaseMailer.implicit_different_template("implicit_multipart").deliver_now
     assert_equal("HTML Implicit Multipart", mail.html_part.body.decoded)
     assert_equal("TEXT Implicit Multipart", mail.text_part.body.decoded)
   end
 
   test "should raise if missing template in implicit render" do
     assert_raises ActionView::MissingTemplate do
-      BaseMailer.implicit_different_template('missing_template').deliver_now
+      BaseMailer.implicit_different_template("missing_template").deliver_now
     end
     assert_equal(0, BaseMailer.deliveries.length)
   end
 
   test "you can specify a different template for explicit render" do
-    mail = BaseMailer.explicit_different_template('explicit_multipart_templates').deliver_now
+    mail = BaseMailer.explicit_different_template("explicit_multipart_templates").deliver_now
     assert_equal("HTML Explicit Multipart Templates", mail.html_part.body.decoded)
     assert_equal("TEXT Explicit Multipart Templates", mail.text_part.body.decoded)
   end
 
   test "you can specify a different layout" do
-    mail = BaseMailer.different_layout('different_layout').deliver_now
+    mail = BaseMailer.different_layout("different_layout").deliver_now
     assert_equal("HTML -- HTML", mail.html_part.body.decoded)
     assert_equal("PLAIN -- PLAIN", mail.text_part.body.decoded)
   end
 
   test "you can specify the template path for implicit lookup" do
-    mail = BaseMailer.welcome_from_another_path('another.path/base_mailer').deliver_now
+    mail = BaseMailer.welcome_from_another_path("another.path/base_mailer").deliver_now
     assert_equal("Welcome from another path", mail.body.encoded)
 
-    mail = BaseMailer.welcome_from_another_path(['unknown/invalid', 'another.path/base_mailer']).deliver_now
+    mail = BaseMailer.welcome_from_another_path(["unknown/invalid", "another.path/base_mailer"]).deliver_now
     assert_equal("Welcome from another path", mail.body.encoded)
   end
 
@@ -589,15 +589,15 @@ class BaseTest < ActiveSupport::TestCase
     assert_dom_equal(%{<img alt="Dummy" src="http://local.com/images/dummy.png" />}, mail.body.to_s.strip)
   end
 
-  test 'the view is not rendered when mail was never called' do
+  test "the view is not rendered when mail was never called" do
     mail = BaseMailer.without_mail_call
-    assert_equal('', mail.body.to_s.strip)
+    assert_equal("", mail.body.to_s.strip)
     mail.deliver_now
   end
 
-  test 'the return value of mailer methods is not relevant' do
+  test "the return value of mailer methods is not relevant" do
     mail = BaseMailer.with_nil_as_return_value
-    assert_equal('Welcome', mail.body.to_s.strip)
+    assert_equal("Welcome", mail.body.to_s.strip)
     mail.deliver_now
   end
 
@@ -708,16 +708,16 @@ class BaseTest < ActiveSupport::TestCase
   end
 
   test "being able to put proc's into the defaults hash and they get evaluated on mail sending" do
-    mail1 = ProcMailer.welcome['X-Proc-Method']
+    mail1 = ProcMailer.welcome["X-Proc-Method"]
     yesterday = 1.day.ago
     Time.stub(:now, yesterday) do
-      mail2 = ProcMailer.welcome['X-Proc-Method']
+      mail2 = ProcMailer.welcome["X-Proc-Method"]
       assert(mail1.to_s.to_i > mail2.to_s.to_i)
     end
   end
 
-  test 'default values which have to_proc (e.g. symbols) should not be considered procs' do
-    assert(ProcMailer.welcome['x-has-to-proc'].to_s == 'symbol')
+  test "default values which have to_proc (e.g. symbols) should not be considered procs" do
+    assert(ProcMailer.welcome["x-has-to-proc"].to_s == "symbol")
   end
 
   test "we can call other defined methods on the class as needed" do
@@ -733,11 +733,11 @@ class BaseTest < ActiveSupport::TestCase
 
       private
       def add_special_header!
-        headers('X-Special-Header' => 'Wow, so special')
+        headers("X-Special-Header" => "Wow, so special")
       end
     end
 
-    assert_equal('Wow, so special', BeforeActionMailer.welcome['X-Special-Header'].to_s)
+    assert_equal("Wow, so special", BeforeActionMailer.welcome["X-Special-Header"].to_s)
   end
 
   test "modifying the mail message with an after_action" do
@@ -748,11 +748,11 @@ class BaseTest < ActiveSupport::TestCase
 
       private
       def add_special_header!
-        headers('X-Special-Header' => 'Testing')
+        headers("X-Special-Header" => "Testing")
       end
     end
 
-    assert_equal('Testing', AfterActionMailer.welcome['X-Special-Header'].to_s)
+    assert_equal("Testing", AfterActionMailer.welcome["X-Special-Header"].to_s)
   end
 
   test "adding an inline attachment using a before_action" do
@@ -763,12 +763,12 @@ class BaseTest < ActiveSupport::TestCase
 
       private
       def add_inline_attachment!
-        attachments.inline["footer.jpg"] = 'hey there'
+        attachments.inline["footer.jpg"] = "hey there"
       end
     end
 
     mail = DefaultInlineAttachmentMailer.welcome
-    assert_equal('image/jpeg; filename=footer.jpg', mail.attachments.inline.first['Content-Type'].to_s)
+    assert_equal("image/jpeg; filename=footer.jpg", mail.attachments.inline.first["Content-Type"].to_s)
   end
 
   test "action methods should be refreshed after defining new method" do
@@ -798,7 +798,7 @@ class BaseTest < ActiveSupport::TestCase
 
   test "default_from can be set" do
     class DefaultFromMailer < ActionMailer::Base
-      default to: 'system@test.lindsaar.net'
+      default to: "system@test.lindsaar.net"
       self.default_options = {from: "robert.pankowecki@gmail.com"}
 
       def welcome
@@ -814,7 +814,7 @@ class BaseTest < ActiveSupport::TestCase
       after_action :a_callback
 
       def welcome
-        headers('X-Special-Header' => 'special indeed!')
+        headers("X-Special-Header" => "special indeed!")
         mail subject: "subject", body: "hello world", to: ["joe@example.com"]
       end
 
diff --git a/actionmailer/test/caching_test.rb b/actionmailer/test/caching_test.rb
index 22e1bdb5f1..4bf8cdb0a4 100644
--- a/actionmailer/test/caching_test.rb
+++ b/actionmailer/test/caching_test.rb
@@ -1,11 +1,11 @@
-require 'fileutils'
-require 'abstract_unit'
-require 'mailers/base_mailer'
-require 'mailers/caching_mailer'
+require "fileutils"
+require "abstract_unit"
+require "mailers/base_mailer"
+require "mailers/caching_mailer"
 
-CACHE_DIR = 'test_cache'
+CACHE_DIR = "test_cache"
 # Don't change '/../temp/' cavalierly or you might hose something you don't want hosed
-FILE_STORE_PATH = File.join(File.dirname(__FILE__), '/../temp/', CACHE_DIR)
+FILE_STORE_PATH = File.join(File.dirname(__FILE__), "/../temp/", CACHE_DIR)
 
 class FragmentCachingMailer < ActionMailer::Base
   abstract!
@@ -23,89 +23,89 @@ class BaseCachingTest < ActiveSupport::TestCase
   end
 
   def test_fragment_cache_key
-    assert_equal 'views/what a key', @mailer.fragment_cache_key('what a key')
+    assert_equal "views/what a key", @mailer.fragment_cache_key("what a key")
   end
 end
 
 class FragmentCachingTest < BaseCachingTest
   def test_read_fragment_with_caching_enabled
-    @store.write('views/name', 'value')
-    assert_equal 'value', @mailer.read_fragment('name')
+    @store.write("views/name", "value")
+    assert_equal "value", @mailer.read_fragment("name")
   end
 
   def test_read_fragment_with_caching_disabled
     @mailer.perform_caching = false
-    @store.write('views/name', 'value')
-    assert_nil @mailer.read_fragment('name')
+    @store.write("views/name", "value")
+    assert_nil @mailer.read_fragment("name")
   end
 
   def test_fragment_exist_with_caching_enabled
-    @store.write('views/name', 'value')
-    assert @mailer.fragment_exist?('name')
-    assert !@mailer.fragment_exist?('other_name')
+    @store.write("views/name", "value")
+    assert @mailer.fragment_exist?("name")
+    assert !@mailer.fragment_exist?("other_name")
   end
 
   def test_fragment_exist_with_caching_disabled
     @mailer.perform_caching = false
-    @store.write('views/name', 'value')
-    assert !@mailer.fragment_exist?('name')
-    assert !@mailer.fragment_exist?('other_name')
+    @store.write("views/name", "value")
+    assert !@mailer.fragment_exist?("name")
+    assert !@mailer.fragment_exist?("other_name")
   end
 
   def test_write_fragment_with_caching_enabled
-    assert_nil @store.read('views/name')
-    assert_equal 'value', @mailer.write_fragment('name', 'value')
-    assert_equal 'value', @store.read('views/name')
+    assert_nil @store.read("views/name")
+    assert_equal "value", @mailer.write_fragment("name", "value")
+    assert_equal "value", @store.read("views/name")
   end
 
   def test_write_fragment_with_caching_disabled
-    assert_nil @store.read('views/name')
+    assert_nil @store.read("views/name")
     @mailer.perform_caching = false
-    assert_equal 'value', @mailer.write_fragment('name', 'value')
-    assert_nil @store.read('views/name')
+    assert_equal "value", @mailer.write_fragment("name", "value")
+    assert_nil @store.read("views/name")
   end
 
   def test_expire_fragment_with_simple_key
-    @store.write('views/name', 'value')
-    @mailer.expire_fragment 'name'
-    assert_nil @store.read('views/name')
+    @store.write("views/name", "value")
+    @mailer.expire_fragment "name"
+    assert_nil @store.read("views/name")
   end
 
   def test_expire_fragment_with_regexp
-    @store.write('views/name', 'value')
-    @store.write('views/another_name', 'another_value')
-    @store.write('views/primalgrasp', 'will not expire ;-)')
+    @store.write("views/name", "value")
+    @store.write("views/another_name", "another_value")
+    @store.write("views/primalgrasp", "will not expire ;-)")
 
     @mailer.expire_fragment(/name/)
 
-    assert_nil @store.read('views/name')
-    assert_nil @store.read('views/another_name')
-    assert_equal 'will not expire ;-)', @store.read('views/primalgrasp')
+    assert_nil @store.read("views/name")
+    assert_nil @store.read("views/another_name")
+    assert_equal "will not expire ;-)", @store.read("views/primalgrasp")
   end
 
   def test_fragment_for
-    @store.write('views/expensive', 'fragment content')
+    @store.write("views/expensive", "fragment content")
     fragment_computed = false
 
     view_context = @mailer.view_context
 
-    buffer = 'generated till now -> '.html_safe
-    buffer << view_context.send(:fragment_for, 'expensive') { fragment_computed = true }
+    buffer = "generated till now -> ".html_safe
+    buffer << view_context.send(:fragment_for, "expensive") { fragment_computed = true }
 
     assert !fragment_computed
-    assert_equal 'generated till now -> fragment content', buffer
+    assert_equal "generated till now -> fragment content", buffer
   end
 
   def test_html_safety
-    assert_nil @store.read('views/name')
-    content = 'value'.html_safe
-    assert_equal content, @mailer.write_fragment('name', content)
+    assert_nil @store.read("views/name")
+    content = "value".html_safe
+    assert_equal content, @mailer.write_fragment("name", content)
 
-    cached = @store.read('views/name')
+    cached = @store.read("views/name")
     assert_equal content, cached
     assert_equal String, cached.class
 
-    html_safe = @mailer.read_fragment('name')
+    html_safe = @mailer.read_fragment("name")
     assert_equal content, html_safe
     assert html_safe.html_safe?
   end
@@ -131,7 +131,7 @@ class FunctionalFragmentCachingTest < BaseCachingTest
 
   def test_fragment_caching_in_partials
     email = @mailer.fragment_cache_in_partials
-    expected_body = 'Old fragment caching in a partial'
+    expected_body = "Old fragment caching in a partial"
     assert_match(expected_body, email.body.encoded)
 
     assert_match(expected_body,
@@ -224,7 +224,7 @@ class CacheHelperOutputBufferTest < BaseCachingTest
       cache_helper.stub :output_buffer, output_buffer do
         assert_called_with cache_helper, :output_buffer=, [output_buffer.class.new(output_buffer)] do
           assert_nothing_raised do
-            cache_helper.send :fragment_for, 'Test fragment name', 'Test fragment', &Proc.new{ nil }
+            cache_helper.send :fragment_for, "Test fragment name", "Test fragment", &Proc.new{ nil }
           end
         end
       end
@@ -245,7 +245,7 @@ class CacheHelperOutputBufferTest < BaseCachingTest
       cache_helper.stub :output_buffer, output_buffer do
         assert_called_with cache_helper, :output_buffer=, [output_buffer.class.new(output_buffer)] do
           assert_nothing_raised do
-            cache_helper.send :fragment_for, 'Test fragment name', 'Test fragment', &Proc.new{ nil }
+            cache_helper.send :fragment_for, "Test fragment name", "Test fragment", &Proc.new{ nil }
           end
         end
       end
diff --git a/actionmailer/test/delivery_methods_test.rb b/actionmailer/test/delivery_methods_test.rb
index bcbd036f26..a508c0aae9 100644
--- a/actionmailer/test/delivery_methods_test.rb
+++ b/actionmailer/test/delivery_methods_test.rb
@@ -1,4 +1,4 @@
-require 'abstract_unit'
+require "abstract_unit"
 
 class MyCustomDelivery
 end
@@ -23,7 +23,7 @@ class DefaultsDeliveryMethodsTest < ActiveSupport::TestCase
   test "default smtp settings" do
     settings = { address:              "localhost",
                  port:                 25,
-                 domain:               'localhost.localdomain',
+                 domain:               "localhost.localdomain",
                  user_name:            nil,
                  password:             nil,
                  authentication:       nil,
@@ -38,8 +38,8 @@ class DefaultsDeliveryMethodsTest < ActiveSupport::TestCase
 
   test "default sendmail settings" do
     settings = {
-      location:  '/usr/sbin/sendmail',
-      arguments: '-i'
+      location:  "/usr/sbin/sendmail",
+      arguments: "-i"
     }
     assert_equal settings, ActionMailer::Base.sendmail_settings
   end
@@ -83,8 +83,8 @@ end
 class MailDeliveryTest < ActiveSupport::TestCase
   class DeliveryMailer < ActionMailer::Base
     DEFAULT_HEADERS = {
-      to: 'mikel@test.lindsaar.net',
-      from: 'jose@test.plataformatec.com'
+      to: "mikel@test.lindsaar.net",
+      from: "jose@test.plataformatec.com"
     }
 
     def welcome(hash={})
@@ -145,7 +145,7 @@ class MailDeliveryTest < ActiveSupport::TestCase
     settings = {
       address: "localhost",
       port: 25,
-      domain: 'localhost.localdomain',
+      domain: "localhost.localdomain",
       user_name: nil,
       password: nil,
       authentication: nil,
diff --git a/actionmailer/test/i18n_with_controller_test.rb b/actionmailer/test/i18n_with_controller_test.rb
index 50c4b74eb8..2f91bb6237 100644
--- a/actionmailer/test/i18n_with_controller_test.rb
+++ b/actionmailer/test/i18n_with_controller_test.rb
@@ -1,10 +1,10 @@
-require 'abstract_unit'
-require 'action_view'
-require 'action_controller'
+require "abstract_unit"
+require "action_view"
+require "action_controller"
 
 class I18nTestMailer < ActionMailer::Base
   configure do |c|
-    c.assets_dir = ''
+    c.assets_dir = ""
   end
 
   def mail_with_i18n_subject(recipient)
@@ -26,7 +26,7 @@ class ActionMailerI18nWithControllerTest < ActionDispatch::IntegrationTest
   Routes = ActionDispatch::Routing::RouteSet.new
   Routes.draw do
     ActiveSupport::Deprecation.silence do
-      get ':controller(/:action(/:id))'
+      get ":controller(/:action(/:id))"
     end
   end
 
@@ -56,9 +56,9 @@ class ActionMailerI18nWithControllerTest < ActionDispatch::IntegrationTest
   def test_send_mail
     stub_any_instance(Mail::SMTP, instance: Mail::SMTP.new({})) do |instance|
       assert_called(instance, :deliver!) do
-        with_translation 'de', email_subject: '[Anmeldung] Willkommen' do
+        with_translation "de", email_subject: "[Anmeldung] Willkommen" do
           ActiveSupport::Deprecation.silence do
-            get '/test/send_mail'
+            get "/test/send_mail"
           end
           assert_equal "Mail sent - Subject: [Anmeldung] Willkommen", @response.body
         end
diff --git a/actionmailer/test/log_subscriber_test.rb b/actionmailer/test/log_subscriber_test.rb
index 3871b16840..d864c3acca 100644
--- a/actionmailer/test/log_subscriber_test.rb
+++ b/actionmailer/test/log_subscriber_test.rb
@@ -1,7 +1,7 @@
-require 'abstract_unit'
-require 'mailers/base_mailer'
-require 'active_support/log_subscriber/test_helper'
-require 'action_mailer/log_subscriber'
+require "abstract_unit"
+require "mailers/base_mailer"
+require "active_support/log_subscriber/test_helper"
+require "action_mailer/log_subscriber"
 
 class AMLogSubscriberTest < ActionMailer::TestCase
   include ActiveSupport::LogSubscriber::TestHelper
diff --git a/actionmailer/test/mail_helper_test.rb b/actionmailer/test/mail_helper_test.rb
index ff6b25b0c7..2002d3b636 100644
--- a/actionmailer/test/mail_helper_test.rb
+++ b/actionmailer/test/mail_helper_test.rb
@@ -1,4 +1,4 @@
-require 'abstract_unit'
+require "abstract_unit"
 
 class HelperMailer < ActionMailer::Base
   def use_mail_helper
diff --git a/actionmailer/test/mail_layout_test.rb b/actionmailer/test/mail_layout_test.rb
index 166dd096d4..73059d782d 100644
--- a/actionmailer/test/mail_layout_test.rb
+++ b/actionmailer/test/mail_layout_test.rb
@@ -1,7 +1,7 @@
-require 'abstract_unit'
+require "abstract_unit"
 
 class AutoLayoutMailer < ActionMailer::Base
-  default to: 'test@localhost',
+  default to: "test@localhost",
     subject: "You have a mail",
     from: "tester@example.com"
 
@@ -11,7 +11,7 @@ class AutoLayoutMailer < ActionMailer::Base
 
   def spam
     @world = "Earth"
-    mail(body: render(inline: "Hello, <%= @world %>", layout: 'spam'))
+    mail(body: render(inline: "Hello, <%= @world %>", layout: "spam"))
   end
 
   def nolayout
@@ -28,9 +28,9 @@ class AutoLayoutMailer < ActionMailer::Base
 end
 
 class ExplicitLayoutMailer < ActionMailer::Base
-  layout 'spam', except: [:logout]
+  layout "spam", except: [:logout]
 
-  default to: 'test@localhost',
+  default to: "test@localhost",
     subject: "You have a mail",
     from: "tester@example.com"
 
@@ -54,10 +54,10 @@ class LayoutMailerTest < ActiveSupport::TestCase
     assert_equal "multipart/alternative", mail.mime_type
     assert_equal 2, mail.parts.size
 
-    assert_equal 'text/plain', mail.parts.first.mime_type
+    assert_equal "text/plain", mail.parts.first.mime_type
     assert_equal "text/plain layout - text/plain multipart", mail.parts.first.body.to_s
 
-    assert_equal 'text/html', mail.parts.last.mime_type
+    assert_equal "text/html", mail.parts.last.mime_type
     assert_equal "Hello from layout text/html multipart", mail.parts.last.body.to_s
   end
 
@@ -66,10 +66,10 @@ class LayoutMailerTest < ActiveSupport::TestCase
     assert_equal "multipart/mixed", mail.mime_type
     assert_equal 2, mail.parts.size
 
-    assert_equal 'text/plain', mail.parts.first.mime_type
+    assert_equal "text/plain", mail.parts.first.mime_type
     assert_equal "text/plain layout - text/plain multipart", mail.parts.first.body.to_s
 
-    assert_equal 'text/html', mail.parts.last.mime_type
+    assert_equal "text/html", mail.parts.last.mime_type
     assert_equal "Hello from layout text/html multipart", mail.parts.last.body.to_s
   end
 
diff --git a/actionmailer/test/mailers/base_mailer.rb b/actionmailer/test/mailers/base_mailer.rb
index 8c2225ce60..fd7397be84 100644
--- a/actionmailer/test/mailers/base_mailer.rb
+++ b/actionmailer/test/mailers/base_mailer.rb
@@ -1,12 +1,12 @@
 class BaseMailer < ActionMailer::Base
   self.mailer_name = "base_mailer"
 
-  default to: 'system@test.lindsaar.net',
-          from: 'jose@test.plataformatec.com',
-          reply_to: 'mikel@test.lindsaar.net'
+  default to: "system@test.lindsaar.net",
+          from: "jose@test.plataformatec.com",
+          reply_to: "mikel@test.lindsaar.net"
 
   def welcome(hash = {})
-    headers['X-SPAM'] = "Not SPAM"
+    headers["X-SPAM"] = "Not SPAM"
     mail({subject: "The first email on new API!"}.merge!(hash))
   end
 
@@ -28,30 +28,30 @@ class BaseMailer < ActionMailer::Base
   end
 
   def inline_attachment
-    attachments.inline['logo.png'] = "\312\213\254\232"
+    attachments.inline["logo.png"] = "\312\213\254\232"
     mail
   end
 
   def attachment_with_content(hash = {})
-    attachments['invoice.pdf'] = 'This is test File content'
+    attachments["invoice.pdf"] = "This is test File content"
     mail(hash)
   end
 
   def attachment_with_hash
-    attachments['invoice.jpg'] = { data: ::Base64.encode64("\312\213\254\232)b"),
+    attachments["invoice.jpg"] = { data: ::Base64.encode64("\312\213\254\232)b"),
                                    mime_type: "image/x-jpg",
                                    transfer_encoding: "base64" }
     mail
   end
 
   def attachment_with_hash_default_encoding
-    attachments['invoice.jpg'] = { data: "\312\213\254\232)b",
+    attachments["invoice.jpg"] = { data: "\312\213\254\232)b",
                                    mime_type: "image/x-jpg" }
     mail
   end
 
   def implicit_multipart(hash = {})
-    attachments['invoice.pdf'] = 'This is test File content' if hash.delete(:attachments)
+    attachments["invoice.pdf"] = "This is test File content" if hash.delete(:attachments)
     mail(hash)
   end
 
@@ -60,7 +60,7 @@ class BaseMailer < ActionMailer::Base
   end
 
   def explicit_multipart(hash = {})
-    attachments['invoice.pdf'] = 'This is test File content' if hash.delete(:attachments)
+    attachments["invoice.pdf"] = "This is test File content" if hash.delete(:attachments)
     mail(hash) do |format|
       format.text { render text: "TEXT Explicit Multipart" }
       format.html { render text: "HTML Explicit Multipart" }
@@ -100,18 +100,18 @@ class BaseMailer < ActionMailer::Base
     end
   end
 
-  def implicit_different_template(template_name='')
+  def implicit_different_template(template_name="")
     mail(template_name: template_name)
   end
 
-  def explicit_different_template(template_name='')
+  def explicit_different_template(template_name="")
     mail do |format|
       format.text { render template: "#{mailer_name}/#{template_name}" }
       format.html { render template: "#{mailer_name}/#{template_name}" }
     end
   end
 
-  def different_layout(layout_name='')
+  def different_layout(layout_name="")
     mail do |format|
       format.text { render layout: layout_name }
       format.html { render layout: layout_name }
@@ -131,6 +131,6 @@ class BaseMailer < ActionMailer::Base
   end
 
   def with_subject_interpolations
-    mail(subject: default_i18n_subject(rapper_or_impersonator: 'Slim Shady'), body: '')
+    mail(subject: default_i18n_subject(rapper_or_impersonator: "Slim Shady"), body: "")
   end
 end
diff --git a/actionmailer/test/mailers/delayed_mailer.rb b/actionmailer/test/mailers/delayed_mailer.rb
index e6211ef028..cae4ec2f48 100644
--- a/actionmailer/test/mailers/delayed_mailer.rb
+++ b/actionmailer/test/mailers/delayed_mailer.rb
@@ -1,4 +1,4 @@
-require 'active_job/arguments'
+require "active_job/arguments"
 
 class DelayedMailerError < StandardError; end
 
@@ -17,10 +17,10 @@ class DelayedMailer < ActionMailer::Base
   end
 
   def test_message(*)
-    mail(from: 'test-sender@test.com', to: 'test-receiver@test.com', subject: 'Test Subject', body: 'Test Body')
+    mail(from: "test-sender@test.com", to: "test-receiver@test.com", subject: "Test Subject", body: "Test Body")
   end
 
   def test_raise(klass_name)
-    raise klass_name.constantize, 'boom'
+    raise klass_name.constantize, "boom"
   end
 end
diff --git a/actionmailer/test/mailers/proc_mailer.rb b/actionmailer/test/mailers/proc_mailer.rb
index 7e189d861f..f5371fa674 100644
--- a/actionmailer/test/mailers/proc_mailer.rb
+++ b/actionmailer/test/mailers/proc_mailer.rb
@@ -1,8 +1,8 @@
 class ProcMailer < ActionMailer::Base
-  default to: 'system@test.lindsaar.net',
-          'X-Proc-Method' => Proc.new { Time.now.to_i.to_s },
+  default to: "system@test.lindsaar.net",
+          "X-Proc-Method" => Proc.new { Time.now.to_i.to_s },
           subject: Proc.new { give_a_greeting },
-          'x-has-to-proc' => :symbol
+          "x-has-to-proc" => :symbol
 
   def welcome
     mail
diff --git a/actionmailer/test/message_delivery_test.rb b/actionmailer/test/message_delivery_test.rb
index aaed94d519..0eb81a8496 100644
--- a/actionmailer/test/message_delivery_test.rb
+++ b/actionmailer/test/message_delivery_test.rb
@@ -1,6 +1,6 @@
-require 'abstract_unit'
-require 'active_job'
-require 'mailers/delayed_mailer'
+require "abstract_unit"
+require "active_job"
+require "mailers/delayed_mailer"
 
 class MessageDeliveryTest < ActiveSupport::TestCase
   include ActiveJob::TestHelper
@@ -31,27 +31,27 @@ class MessageDeliveryTest < ActiveSupport::TestCase
     DelayedMailer.last_rescue_from_instance = nil
   end
 
-  test 'should have a message' do
+  test "should have a message" do
     assert @mail.message
   end
 
-  test 'its message should be a Mail::Message' do
+  test "its message should be a Mail::Message" do
     assert_equal Mail::Message , @mail.message.class
   end
 
-  test 'should respond to .deliver_later' do
+  test "should respond to .deliver_later" do
     assert_respond_to @mail, :deliver_later
   end
 
-  test 'should respond to .deliver_later!' do
+  test "should respond to .deliver_later!" do
     assert_respond_to @mail, :deliver_later!
   end
 
-  test 'should respond to .deliver_now' do
+  test "should respond to .deliver_now" do
     assert_respond_to @mail, :deliver_now
   end
 
-  test 'should respond to .deliver_now!' do
+  test "should respond to .deliver_now!" do
     assert_respond_to @mail, :deliver_now!
   end
 
@@ -62,46 +62,46 @@ class MessageDeliveryTest < ActiveSupport::TestCase
     ActionMailer::Base.deliveries.clear
   end
 
-  test 'should enqueue the email with :deliver_now delivery method' do
-    assert_performed_with(job: ActionMailer::DeliveryJob, args: ['DelayedMailer', 'test_message', 'deliver_now', 1, 2, 3]) do
+  test "should enqueue the email with :deliver_now delivery method" do
+    assert_performed_with(job: ActionMailer::DeliveryJob, args: ["DelayedMailer", "test_message", "deliver_now", 1, 2, 3]) do
       @mail.deliver_later
     end
   end
 
-  test 'should enqueue the email with :deliver_now! delivery method' do
-    assert_performed_with(job: ActionMailer::DeliveryJob, args: ['DelayedMailer', 'test_message', 'deliver_now!', 1, 2, 3]) do
+  test "should enqueue the email with :deliver_now! delivery method" do
+    assert_performed_with(job: ActionMailer::DeliveryJob, args: ["DelayedMailer", "test_message", "deliver_now!", 1, 2, 3]) do
       @mail.deliver_later!
     end
   end
 
-  test 'should enqueue a delivery with a delay' do
+  test "should enqueue a delivery with a delay" do
     travel_to Time.new(2004, 11, 24, 01, 04, 44) do
-      assert_performed_with(job: ActionMailer::DeliveryJob, at: Time.current.to_f+600.seconds, args: ['DelayedMailer', 'test_message', 'deliver_now', 1, 2, 3]) do
+      assert_performed_with(job: ActionMailer::DeliveryJob, at: Time.current.to_f+600.seconds, args: ["DelayedMailer", "test_message", "deliver_now", 1, 2, 3]) do
         @mail.deliver_later wait: 600.seconds
       end
     end
   end
 
-  test 'should enqueue a delivery at a specific time' do
+  test "should enqueue a delivery at a specific time" do
     later_time = Time.now.to_f + 3600
-    assert_performed_with(job: ActionMailer::DeliveryJob, at: later_time, args: ['DelayedMailer', 'test_message', 'deliver_now', 1, 2, 3]) do
+    assert_performed_with(job: ActionMailer::DeliveryJob, at: later_time, args: ["DelayedMailer", "test_message", "deliver_now", 1, 2, 3]) do
       @mail.deliver_later wait_until: later_time
     end
   end
 
-  test 'should enqueue the job on the correct queue' do
-    assert_performed_with(job: ActionMailer::DeliveryJob, args: ['DelayedMailer', 'test_message', 'deliver_now', 1, 2, 3], queue: "test_queue") do
+  test "should enqueue the job on the correct queue" do
+    assert_performed_with(job: ActionMailer::DeliveryJob, args: ["DelayedMailer", "test_message", "deliver_now", 1, 2, 3], queue: "test_queue") do
       @mail.deliver_later
     end
   end
 
-  test 'can override the queue when enqueuing mail' do
-    assert_performed_with(job: ActionMailer::DeliveryJob, args: ['DelayedMailer', 'test_message', 'deliver_now', 1, 2, 3], queue: "another_queue") do
+  test "can override the queue when enqueuing mail" do
+    assert_performed_with(job: ActionMailer::DeliveryJob, args: ["DelayedMailer", "test_message", "deliver_now", 1, 2, 3], queue: "another_queue") do
       @mail.deliver_later(queue: :another_queue)
     end
   end
 
-  test 'deliver_later after accessing the message is disallowed' do
+  test "deliver_later after accessing the message is disallowed" do
     @mail.message # Load the message, which calls the mailer method.
 
     assert_raise RuntimeError do
@@ -109,17 +109,17 @@ class MessageDeliveryTest < ActiveSupport::TestCase
     end
   end
 
-  test 'job delegates error handling to mailer' do
+  test "job delegates error handling to mailer" do
     # Superclass not rescued by mailer's rescue_from RuntimeError
-    message = DelayedMailer.test_raise('StandardError')
+    message = DelayedMailer.test_raise("StandardError")
     assert_raise(StandardError) { message.deliver_later }
     assert_nil DelayedMailer.last_error
     assert_nil DelayedMailer.last_rescue_from_instance
 
     # Rescued by mailer's rescue_from RuntimeError
-    message = DelayedMailer.test_raise('DelayedMailerError')
+    message = DelayedMailer.test_raise("DelayedMailerError")
     assert_nothing_raised { message.deliver_later }
-    assert_equal 'boom', DelayedMailer.last_error.message
+    assert_equal "boom", DelayedMailer.last_error.message
     assert_kind_of DelayedMailer, DelayedMailer.last_rescue_from_instance
   end
 
@@ -127,7 +127,7 @@ class MessageDeliveryTest < ActiveSupport::TestCase
     include GlobalID::Identification
 
     def self.find(id)
-      raise 'boom, missing find'
+      raise "boom, missing find"
     end
 
     attr_reader :id
@@ -136,11 +136,11 @@ class MessageDeliveryTest < ActiveSupport::TestCase
     end
 
     def to_global_id(options = {})
-      super app: 'foo'
+      super app: "foo"
     end
   end
 
-  test 'job delegates deserialization errors to mailer class' do
+  test "job delegates deserialization errors to mailer class" do
     # Inject an argument that can't be deserialized.
     message = DelayedMailer.test_message(DeserializationErrorFixture.new)
 
@@ -148,6 +148,6 @@ class MessageDeliveryTest < ActiveSupport::TestCase
     # on the mailer class.
     assert_nothing_raised { message.deliver_later }
     assert_equal DelayedMailer, DelayedMailer.last_rescue_from_instance
-    assert_equal 'Error while trying to deserialize arguments: boom, missing find', DelayedMailer.last_error.message
+    assert_equal "Error while trying to deserialize arguments: boom, missing find", DelayedMailer.last_error.message
   end
 end
diff --git a/actionmailer/test/test_case_test.rb b/actionmailer/test/test_case_test.rb
index 5d8d3c3b36..193d107b0a 100644
--- a/actionmailer/test/test_case_test.rb
+++ b/actionmailer/test/test_case_test.rb
@@ -1,4 +1,4 @@
-require 'abstract_unit'
+require "abstract_unit"
 
 class TestTestMailer < ActionMailer::Base
 end
@@ -8,7 +8,7 @@ class ClearTestDeliveriesMixinTest < ActiveSupport::TestCase
 
   def before_setup
     ActionMailer::Base.delivery_method, @original_delivery_method = :test, ActionMailer::Base.delivery_method
-    ActionMailer::Base.deliveries << 'better clear me, setup'
+    ActionMailer::Base.deliveries << "better clear me, setup"
     super
   end
 
@@ -20,13 +20,13 @@ class ClearTestDeliveriesMixinTest < ActiveSupport::TestCase
 
   def test_deliveries_are_cleared_on_setup_and_teardown
     assert_equal [], ActionMailer::Base.deliveries
-    ActionMailer::Base.deliveries << 'better clear me, teardown'
+    ActionMailer::Base.deliveries << "better clear me, teardown"
   end
 end
 
 class MailerDeliveriesClearingTest < ActionMailer::TestCase
   def before_setup
-    ActionMailer::Base.deliveries << 'better clear me, setup'
+    ActionMailer::Base.deliveries << "better clear me, setup"
     super
   end
 
@@ -37,7 +37,7 @@ class MailerDeliveriesClearingTest < ActionMailer::TestCase
 
   def test_deliveries_are_cleared_on_setup_and_teardown
     assert_equal [], ActionMailer::Base.deliveries
-    ActionMailer::Base.deliveries << 'better clear me, teardown'
+    ActionMailer::Base.deliveries << "better clear me, teardown"
   end
 end
 
@@ -58,7 +58,7 @@ class CrazySymbolNameMailerTest < ActionMailer::TestCase
 end
 
 class CrazyStringNameMailerTest < ActionMailer::TestCase
-  tests 'test_test_mailer'
+  tests "test_test_mailer"
 
   def test_set_mailer_class_manual_using_string
     assert_equal TestTestMailer, self.class.mailer_class
diff --git a/actionmailer/test/test_helper_test.rb b/actionmailer/test/test_helper_test.rb
index 0a4bc75d3e..31ac5a5211 100644
--- a/actionmailer/test/test_helper_test.rb
+++ b/actionmailer/test/test_helper_test.rb
@@ -1,5 +1,5 @@
-require 'abstract_unit'
-require 'active_support/testing/stream'
+require "abstract_unit"
+require "active_support/testing/stream"
 
 class TestHelperMailer < ActionMailer::Base
   def test
@@ -40,11 +40,11 @@ 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 "=?UTF-8?Q?This_is_=E3=81=82_string?=", encode("This is あ string")
   end
 
   def test_read_fixture
-    assert_equal ['Welcome!'], read_fixture('welcome')
+    assert_equal ["Welcome!"], read_fixture("welcome")
   end
 
   def test_assert_emails
@@ -198,6 +198,6 @@ class AnotherTestHelperMailerTest < ActionMailer::TestCase
 
   def test_setup_shouldnt_conflict_with_mailer_setup
     assert_kind_of Mail::Message, @expected
-    assert_equal 'a value', @test_var
+    assert_equal "a value", @test_var
   end
 end
diff --git a/actionmailer/test/url_test.rb b/actionmailer/test/url_test.rb
index 70bd05055f..9e393c9e49 100644
--- a/actionmailer/test/url_test.rb
+++ b/actionmailer/test/url_test.rb
@@ -1,5 +1,5 @@
-require 'abstract_unit'
-require 'action_controller'
+require "abstract_unit"
+require "action_controller"
 
 class WelcomeController < ActionController::Base
 end
@@ -11,10 +11,10 @@ class ActionMailer::Base
 end
 
 class UrlTestMailer < ActionMailer::Base
-  default_url_options[:host] = 'www.basecamphq.com'
+  default_url_options[:host] = "www.basecamphq.com"
 
   configure do |c|
-    c.assets_dir = '' # To get the tests to pass
+    c.assets_dir = "" # To get the tests to pass
   end
 
   def signed_up_with_url(recipient)
@@ -27,14 +27,14 @@ class UrlTestMailer < ActionMailer::Base
   def exercise_url_for(options)
     @options = options
     @url = url_for(@options)
-    mail(from: 'from@example.com', to: 'to@example.com', subject: 'subject')
+    mail(from: "from@example.com", to: "to@example.com", subject: "subject")
   end
 end
 
 class ActionMailerUrlTest < ActionMailer::TestCase
   class DummyModel
     def self.model_name
-      OpenStruct.new(route_key: 'dummy_model')
+      OpenStruct.new(route_key: "dummy_model")
     end
 
     def persisted?
@@ -64,7 +64,7 @@ class ActionMailerUrlTest < ActionMailer::TestCase
   end
 
   def assert_url_for(expected, options, relative = false)
-    expected = "http://www.basecamphq.com#{expected}" if expected.start_with?('/') && !relative
+    expected = "http://www.basecamphq.com#{expected}" if expected.start_with?("/") && !relative
     urls = UrlTestMailer.exercise_url_for(options).body.to_s.chomp.split
 
     assert_equal expected, urls.first
@@ -72,7 +72,7 @@ class ActionMailerUrlTest < ActionMailer::TestCase
   end
 
   def setup
-    @recipient = 'test@localhost'
+    @recipient = "test@localhost"
   end
 
   def test_url_for
@@ -80,30 +80,30 @@ class ActionMailerUrlTest < ActionMailer::TestCase
 
     AppRoutes.draw do
       ActiveSupport::Deprecation.silence do
-        get ':controller(/:action(/:id))'
-        get '/welcome'  => 'foo#bar', as: 'welcome'
-        get '/dummy_model' => 'foo#baz', as: 'dummy_model'
+        get ":controller(/:action(/:id))"
+        get "/welcome"  => "foo#bar", as: "welcome"
+        get "/dummy_model" => "foo#baz", as: "dummy_model"
       end
     end
 
     # string
-    assert_url_for 'http://foo/', 'http://foo/'
+    assert_url_for "http://foo/", "http://foo/"
 
     # symbol
-    assert_url_for '/welcome', :welcome
+    assert_url_for "/welcome", :welcome
 
     # hash
-    assert_url_for '/a/b/c', controller: 'a', action: 'b', id: 'c'
-    assert_url_for '/a/b/c', {controller: 'a', action: 'b', id: 'c', only_path: true}, true
+    assert_url_for "/a/b/c", controller: "a", action: "b", id: "c"
+    assert_url_for "/a/b/c", {controller: "a", action: "b", id: "c", only_path: true}, true
 
     # model
-    assert_url_for '/dummy_model', DummyModel.new
+    assert_url_for "/dummy_model", DummyModel.new
 
     # class
-    assert_url_for '/dummy_model', DummyModel
+    assert_url_for "/dummy_model", DummyModel
 
     # array
-    assert_url_for '/dummy_model' , [DummyModel]
+    assert_url_for "/dummy_model" , [DummyModel]
   end
 
   def test_signed_up_with_url
@@ -111,8 +111,8 @@ class ActionMailerUrlTest < ActionMailer::TestCase
 
     AppRoutes.draw do
       ActiveSupport::Deprecation.silence do
-        get ':controller(/:action(/:id))'
-        get '/welcome' => "foo#bar", as: "welcome"
+        get ":controller(/:action(/:id))"
+        get "/welcome" => "foo#bar", as: "welcome"
       end
     end
 
@@ -128,15 +128,15 @@ class ActionMailerUrlTest < ActionMailer::TestCase
     assert_nothing_raised { created = UrlTestMailer.signed_up_with_url(@recipient) }
     assert_not_nil created
 
-    expected.message_id = '<123@456>'
-    created.message_id = '<123@456>'
+    expected.message_id = "<123@456>"
+    created.message_id = "<123@456>"
     assert_dom_equal expected.encoded, created.encoded
 
     assert_nothing_raised { UrlTestMailer.signed_up_with_url(@recipient).deliver_now }
     assert_not_nil ActionMailer::Base.deliveries.first
     delivered = ActionMailer::Base.deliveries.first
 
-    delivered.message_id = '<123@456>'
+    delivered.message_id = "<123@456>"
     assert_dom_equal expected.encoded, delivered.encoded
   end
 end