Freeze literals

Author: ka8725

lib/rspec/rails/matchers/send_email.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module RSpec
   module Rails
     module Matchers
@@ -7,7 +9,7 @@ module Matchers
       #
       # @see RSpec::Rails::Matchers#send_email
       class SendEmail < RSpec::Rails::Matchers::BaseMatcher
-        INSPECT_EMAIL_ATTRIBUTES = %i[subject from to cc bcc]
+        INSPECT_EMAIL_ATTRIBUTES = %i[subject from to cc bcc].freeze
 
         def initialize(criteria)
           @criteria = criteria

spec/rspec/rails/matchers/send_email_spec.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 RSpec.describe "send_email" do
   it "checks email sending by all params together" do
     expect {