test: update tests to use frozen string literals

so that ruby 3.4 doesn't emit so many warnings.

test/test_mechanize.rb

@@ -1,4 +1,5 @@
 # coding: utf-8
+# frozen_string_literal: true
 
 require 'mechanize/test_case'
 

test/test_mechanize_cookie.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'mechanize/test_case'
 
 module Enumerable

test/test_mechanize_cookie_jar.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'mechanize/test_case'
 require 'fileutils'
 

test/test_mechanize_directory_saver.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'mechanize/test_case'
 
 class TestMechanizeDirectorySaver < Mechanize::TestCase

test/test_mechanize_download.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'mechanize/test_case'
 
 class TestMechanizeDownload < Mechanize::TestCase

test/test_mechanize_element_not_found_error.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'mechanize/test_case'
 
 class TestMechanizeRedirectLimitReachedError < Mechanize::TestCase

test/test_mechanize_file.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'mechanize/test_case'
 
 class TestMechanizeFile < Mechanize::TestCase

test/test_mechanize_file_connection.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'mechanize/test_case'
 
 class TestMechanizeFileConnection < Mechanize::TestCase
@@ -7,7 +8,7 @@ def test_request
     uri = URI.parse "file://#{file_path}"
     conn = Mechanize::FileConnection.new
 
-    body = ''
+    body = +''
 
     conn.request uri, nil do |response|
       assert_equal(file_path, response.file_path)

test/test_mechanize_file_request.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'mechanize/test_case'
 
 class TestMechanizeFileRequest < Mechanize::TestCase

test/test_mechanize_file_response.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'mechanize/test_case'
 
 class TestMechanizeFileResponse < Mechanize::TestCase

test/test_mechanize_file_saver.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'mechanize/test_case'
 
 class TestMechanizeFileSaver < Mechanize::TestCase

test/test_mechanize_form.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'mechanize/test_case'
 
 class TestMechanizeForm < Mechanize::TestCase

test/test_mechanize_form_check_box.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'mechanize/test_case'
 
 class TestMechanizeFormCheckBox < Mechanize::TestCase

test/test_mechanize_form_encoding.rb

@@ -1,4 +1,5 @@
 # coding: utf-8
+# frozen_string_literal: true
 require 'mechanize/test_case'
 
 class TestMechanizeFormEncoding < Mechanize::TestCase
@@ -8,7 +9,7 @@ class TestMechanizeFormEncoding < Mechanize::TestCase
 
   INPUTTED_VALUE = "テスト" # "test" in Japanese UTF-8 encoding
   CONTENT_ENCODING = 'Shift_JIS' # one of Japanese encoding
-  encoded_value = "\x83\x65\x83\x58\x83\x67".force_encoding(::Encoding::SHIFT_JIS) # "test" in Japanese Shift_JIS encoding
+  encoded_value = "\x83\x65\x83\x58\x83\x67".dup.force_encoding(::Encoding::SHIFT_JIS) # "test" in Japanese Shift_JIS encoding
   EXPECTED_QUERY = "first_name=#{CGI.escape(encoded_value)}&first_name=&gender=&green%5Beggs%5D="
 
   ENCODING_ERRORS = [EncodingError, Encoding::ConverterNotFoundError] # and so on

test/test_mechanize_form_field.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'mechanize/test_case'
 
 class TestMechanizeFormField < Mechanize::TestCase

test/test_mechanize_form_file_upload.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'mechanize/test_case'
 
 class TestMechanizeFormFileUpload < Mechanize::TestCase

test/test_mechanize_form_image_button.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'mechanize/test_case'
 
 class TestMechanizeFormImageButton < Mechanize::TestCase

test/test_mechanize_form_keygen.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'mechanize/test_case'
 
 class TestMechanizeFormKeygen < Mechanize::TestCase

test/test_mechanize_form_multi_select_list.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'mechanize/test_case'
 
 class TestMechanizeFormMultiSelectList < Mechanize::TestCase

test/test_mechanize_form_option.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'mechanize/test_case'
 
 class TestMechanizeFormOption < Mechanize::TestCase

test/test_mechanize_form_radio_button.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'mechanize/test_case'
 
 class TestMechanizeFormRadioButton < Mechanize::TestCase

test/test_mechanize_form_select_list.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'mechanize/test_case'
 
 class TestMechanizeFormSelectList < Mechanize::TestCase

test/test_mechanize_form_textarea.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'mechanize/test_case'
 
 class TestMechanizeFormTextarea < Mechanize::TestCase

test/test_mechanize_headers.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'mechanize/test_case'
 
 class TestMechanizeHeaders < Mechanize::TestCase

test/test_mechanize_history.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'mechanize/test_case'
 
 class TestMechanizeHistory < Mechanize::TestCase

test/test_mechanize_http_agent.rb

@@ -1,4 +1,5 @@
 # coding: utf-8
+# frozen_string_literal: true
 
 require 'mechanize/test_case'
 
@@ -1027,7 +1028,7 @@ def test_response_content_encoding_gzip_encoding_bad
 
     body = @agent.response_content_encoding @res, body_io
 
-    expected = "test\xB2"
+    expected = +"test\xB2"
     expected.force_encoding Encoding::BINARY if have_encoding?
 
     content = body.read
@@ -1432,11 +1433,11 @@ def test_response_read_file
 
       io = @agent.response_read res, req, uri
 
-      expected = "π\n".force_encoding(Encoding::BINARY)
+      expected = "π\n".dup.force_encoding(Encoding::BINARY)
 
       # Ruby 1.8.7 doesn't let us set the write mode of the tempfile to binary,
       # so we should expect an inserted carriage return on some platforms
-      expected_with_carriage_return = "π\r\n".force_encoding(Encoding::BINARY)
+      expected_with_carriage_return = "π\r\n".dup.force_encoding(Encoding::BINARY)
 
       body = io.read
       assert_match(/^(#{expected}|#{expected_with_carriage_return})$/m, body)

test/test_mechanize_http_auth_challenge.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'mechanize/test_case'
 
 class TestMechanizeHttpAuthChallenge < Mechanize::TestCase

test/test_mechanize_http_auth_realm.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'mechanize/test_case'
 
 class TestMechanizeHttpAuthRealm < Mechanize::TestCase

test/test_mechanize_http_auth_store.rb

@@ -1,4 +1,5 @@
 # coding: utf-8
+# frozen_string_literal: true
 
 require 'mechanize/test_case'
 

test/test_mechanize_http_content_disposition_parser.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'mechanize/test_case'
 
 class TestMechanizeHttpContentDispositionParser < Mechanize::TestCase

test/test_mechanize_http_www_authenticate_parser.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'mechanize/test_case'
 
 class TestMechanizeHttpWwwAuthenticateParser < Mechanize::TestCase

test/test_mechanize_image.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'mechanize/test_case'
 
 class TestMechanizeImage < Mechanize::TestCase

test/test_mechanize_link.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'mechanize/test_case'
 
 class TestMechanizeLink < Mechanize::TestCase

test/test_mechanize_page.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'mechanize/test_case'
 
 class TestMechanizePage < Mechanize::TestCase

test/test_mechanize_page_encoding.rb

@@ -1,4 +1,5 @@
 # -*- coding: utf-8 -*-
+# frozen_string_literal: true
 require 'mechanize/test_case'
 
 # tests for Page encoding and charset and parsing
@@ -12,7 +13,7 @@ def setup
 
     @uri = URI('http://localhost/')
     @response_headers = { 'content-type' => 'text/html' }
-    @body = '<title>hi</title>'
+    @body = +'<title>hi</title>'
   end
 
   def util_page body = @body, headers = @response_headers
@@ -118,7 +119,7 @@ def test_page_meta_charset_handles_whitespace
   end
 
   def test_meta_charset
-    body = '<meta http-equiv="content-type" content="text/html;charset=META">'
+    body = +'<meta http-equiv="content-type" content="text/html;charset=META">'
     page = util_page body
 
     assert_equal ['META'], page.meta_charset
@@ -132,7 +133,7 @@ def test_detected_encoding
 
   def test_encodings
     response = {'content-type' => 'text/html;charset=HEADER'}
-    body = '<meta http-equiv="content-type" content="text/html;charset=META">'
+    body = +'<meta http-equiv="content-type" content="text/html;charset=META">'
     @mech.default_encoding = 'DEFAULT'
     page = util_page body, response
 
@@ -175,7 +176,7 @@ def test_parser_encoding_equals_overwrites_force_default_encoding
   def test_parser_encoding_when_searching_elements
     skip "Encoding not implemented" unless have_encoding?
 
-    body = '<span id="latin1">hi</span>'
+    body = +'<span id="latin1">hi</span>'
     page = util_page body, 'content-type' => 'text/html,charset=ISO-8859-1'
 
     result = page.search('#latin1')
@@ -187,7 +188,7 @@ def test_parser_error_message_containing_encoding_errors
     skip if RUBY_ENGINE == 'jruby' # this is a libxml2-specific condition
 
     # https://github.com/sparklemotion/mechanize/issues/553
-    body = <<~EOF
+    body = +<<~EOF
       <html>
       <body>
       <!--

test/test_mechanize_page_frame.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'mechanize/test_case'
 
 class TestMechanizePageFrame < Mechanize::TestCase

test/test_mechanize_page_image.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'mechanize/test_case'
 
 class TestMechanizePageImage < Mechanize::TestCase

test/test_mechanize_page_link.rb

@@ -1,4 +1,5 @@
 # coding: utf-8
+# frozen_string_literal: true
 
 require 'mechanize/test_case'
 
@@ -11,7 +12,7 @@ class TestMechanizePageLink < Mechanize::TestCase
 <title>hi</title>
   HTML
 
-  BAD = <<-HTML
+  BAD = <<-HTML.dup
 <meta http-equiv="content-type" content="text/html; charset=windows-1255">
 <title>Bia\xB3ystok</title>
   HTML
@@ -46,7 +47,7 @@ def setup
 
     @uri = URI('http://example')
     @res = { 'content-type' => 'text/html' }
-    @body = '<title>hi</title>'
+    @body = +'<title>hi</title>'
   end
 
   def util_page body = @body, res = @res
@@ -75,7 +76,7 @@ def test_canonical_uri
   end
 
   def test_canonical_uri_unescaped
-    page = util_page <<-BODY
+    page = util_page(+<<-BODY)
 <head>
   <link rel="canonical" href="http://example/white space"/>
 </head>
@@ -97,7 +98,7 @@ def test_charset_from_bad_content_type
   end
 
   def test_encoding
-    page = util_page WINDOWS_1255
+    page = util_page WINDOWS_1255.dup
 
     assert_equal 'windows-1255', page.encoding
   end
@@ -153,7 +154,7 @@ def test_encoding_charset_bad
   end
 
   def test_encoding_meta_charset
-    page = util_page "<meta charset='UTF-8'>"
+    page = util_page(+"<meta charset='UTF-8'>")
 
     assert_equal 'UTF-8', page.encoding
   end
@@ -344,7 +345,7 @@ def test_title
   end
 
   def test_title_none
-    page = util_page '' # invalid HTML
+    page = util_page(+'') # invalid HTML
 
     assert_nil(page.title)
   end

test/test_mechanize_page_meta_refresh.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'mechanize/test_case'
 
 class TestMechanizePageMetaRefresh < Mechanize::TestCase

test/test_mechanize_parser.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'mechanize/test_case'
 
 class TestMechanizeParser < Mechanize::TestCase

test/test_mechanize_pluggable_parser.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'mechanize/test_case'
 
 class TestMechanizePluggableParser < Mechanize::TestCase

test/test_mechanize_redirect_limit_reached_error.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'mechanize/test_case'
 
 class TestMechanizeRedirectLimitReachedError < Mechanize::TestCase

test/test_mechanize_redirect_not_get_or_head_error.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'mechanize/test_case'
 
 class TestMechanizeRedirectNotGetOrHead < Mechanize::TestCase

test/test_mechanize_response_read_error.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'mechanize/test_case'
 
 class TestMechanizeResponseReadError < Mechanize::TestCase

test/test_mechanize_subclass.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'mechanize/test_case'
 
 class TestMechanizeSubclass < Mechanize::TestCase