diff --git a/actionmailer/lib/action_mailer/base.rb b/actionmailer/lib/action_mailer/base.rb
index 388f694590..eb8cca9ee4 100644
--- a/actionmailer/lib/action_mailer/base.rb
+++ b/actionmailer/lib/action_mailer/base.rb
@@ -764,7 +764,7 @@ module ActionMailer
       m.charset = charset = headers[:charset]
 
       # Set configure delivery behavior
-      wrap_delivery_behavior!(headers.delete(:delivery_method),headers.delete(:delivery_method_options))
+      wrap_delivery_behavior!(headers.delete(:delivery_method), headers.delete(:delivery_method_options))
 
       # Assign all headers except parts_order, content_type and body
       assignable = headers.except(:parts_order, :content_type, :body, :template_name, :template_path)
diff --git a/actionmailer/test/delivery_methods_test.rb b/actionmailer/test/delivery_methods_test.rb
index 20412c7bb2..609903620b 100644
--- a/actionmailer/test/delivery_methods_test.rb
+++ b/actionmailer/test/delivery_methods_test.rb
@@ -38,8 +38,10 @@ class DefaultsDeliveryMethodsTest < ActiveSupport::TestCase
   end
 
   test "default sendmail settings" do
-    settings = {location:  '/usr/sbin/sendmail',
-                arguments: '-i -t'}
+    settings = {
+      location:  '/usr/sbin/sendmail',
+      arguments: '-i -t'
+    }
     assert_equal settings, ActionMailer::Base.sendmail_settings
   end
 end
@@ -138,13 +140,15 @@ class MailDeliveryTest < ActiveSupport::TestCase
   end
 
   test "default delivery options can be overridden per mail instance" do
-    settings = { address:              "localhost",
-                 port:                 25,
-                 domain:               'localhost.localdomain',
-                 user_name:            nil,
-                 password:             nil,
-                 authentication:       nil,
-                 enable_starttls_auto: true }
+    settings = {
+      address: "localhost",
+      port: 25,
+      domain: 'localhost.localdomain',
+      user_name: nil,
+      password: nil,
+      authentication: nil,
+      enable_starttls_auto: true
+    }
     assert_equal settings, ActionMailer::Base.smtp_settings
     overridden_options = {user_name: "overridden", password: "somethingobtuse"}
     mail_instance = DeliveryMailer.welcome(delivery_method_options: overridden_options)
@@ -164,6 +168,13 @@ class MailDeliveryTest < ActiveSupport::TestCase
     end
   end
 
+  test "undefined delivery methods raises errors" do
+    DeliveryMailer.delivery_method = nil
+    assert_raise RuntimeError do
+      DeliveryMailer.welcome.deliver
+    end
+  end
+
   test "does not perform deliveries if requested" do
     DeliveryMailer.perform_deliveries = false
     DeliveryMailer.deliveries.clear
diff --git a/activemodel/test/cases/dirty_test.rb b/activemodel/test/cases/dirty_test.rb
index 8b55901a65..2853476c91 100644
--- a/activemodel/test/cases/dirty_test.rb
+++ b/activemodel/test/cases/dirty_test.rb
@@ -41,6 +41,10 @@ class DirtyTest < ActiveModel::TestCase
     def save
       changes_applied
     end
+
+    def reload
+      reset_changes
+    end
   end
 
   setup do
@@ -157,4 +161,19 @@ class DirtyTest < ActiveModel::TestCase
     @model.size = 1
     assert @model.size_changed?
   end
+
+  test "reload should reset all changes" do
+    @model.name = 'Dmitry'
+    @model.name_changed?
+    @model.save
+    @model.name = 'Bob'
+
+    assert_equal [nil, 'Dmitry'], @model.previous_changes['name']
+    assert_equal 'Dmitry', @model.changed_attributes['name']
+
+    @model.reload
+
+    assert_equal ActiveSupport::HashWithIndifferentAccess.new, @model.previous_changes
+    assert_equal ActiveSupport::HashWithIndifferentAccess.new, @model.changed_attributes
+  end
 end
diff --git a/activerecord/lib/active_record/sanitization.rb b/activerecord/lib/active_record/sanitization.rb
index dacaec26b7..5a71c13d91 100644
--- a/activerecord/lib/active_record/sanitization.rb
+++ b/activerecord/lib/active_record/sanitization.rb
@@ -29,6 +29,7 @@ module ActiveRecord
         end
       end
       alias_method :sanitize_sql, :sanitize_sql_for_conditions
+      alias_method :sanitize_conditions, :sanitize_sql
 
       # Accepts an array, hash, or string of SQL conditions and sanitizes
       # them into a valid SQL fragment for a SET clause.
@@ -122,8 +123,6 @@ module ActiveRecord
         end
       end
 
-      alias_method :sanitize_conditions, :sanitize_sql
-
       def replace_bind_variables(statement, values) #:nodoc:
         raise_if_bind_arity_mismatch(statement, statement.count('?'), values.size)
         bound = values.dup
diff --git a/activerecord/test/cases/sanitize_test.rb b/activerecord/test/cases/sanitize_test.rb
index 766b2ff2ef..954eab8022 100644
--- a/activerecord/test/cases/sanitize_test.rb
+++ b/activerecord/test/cases/sanitize_test.rb
@@ -46,4 +46,9 @@ class SanitizeTest < ActiveRecord::TestCase
     select_author_sql = Post.send(:sanitize_sql_array, ['id in (:post_ids)', post_ids: david_posts])
     assert_match(sub_query_pattern, select_author_sql, 'should sanitize `Relation` as subquery for named bind variables')
   end
+
+  def test_sanitize_sql_array_handles_empty_statement
+    select_author_sql = Post.send(:sanitize_sql_array, [''])
+    assert_equal('', select_author_sql)
+  end
 end