make frozen_string_literal: truefrozen

85 files changed, 92 insertions, 91 deletions

diff --git a/ext/psych/extconf.rb b/ext/psych/extconf.rb
index be33d35..6d8390e 100644
--- a/ext/psych/extconf.rb
+++ b/ext/psych/extconf.rb
@@ -1,5 +1,5 @@
 # -*- coding: us-ascii -*-
-# frozen_string_literal: false
+# frozen_string_literal: true
 require 'mkmf'
 require 'fileutils'
 
diff --git a/lib/psych.rb b/lib/psych.rb
index 9959320..2fed434 100644
--- a/lib/psych.rb
+++ b/lib/psych.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require 'psych/versions'
 case RUBY_ENGINE
 when 'jruby'
diff --git a/lib/psych/class_loader.rb b/lib/psych/class_loader.rb
index ba756f7..cfca868 100644
--- a/lib/psych/class_loader.rb
+++ b/lib/psych/class_loader.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require 'psych/omap'
 require 'psych/set'
 
diff --git a/lib/psych/coder.rb b/lib/psych/coder.rb
index 26005f5..96a9c3f 100644
--- a/lib/psych/coder.rb
+++ b/lib/psych/coder.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 module Psych
   ###
   # If an object defines +encode_with+, then an instance of Psych::Coder will
diff --git a/lib/psych/core_ext.rb b/lib/psych/core_ext.rb
index 1232abf..81055cc 100644
--- a/lib/psych/core_ext.rb
+++ b/lib/psych/core_ext.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 class Object
   def self.yaml_tag url
     Psych.add_tag(url, self)
diff --git a/lib/psych/exception.rb b/lib/psych/exception.rb
index 83c3d7f..fac0c42 100644
--- a/lib/psych/exception.rb
+++ b/lib/psych/exception.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 module Psych
   class Exception < RuntimeError
   end
diff --git a/lib/psych/handler.rb b/lib/psych/handler.rb
index 1ab5f73..1074c18 100644
--- a/lib/psych/handler.rb
+++ b/lib/psych/handler.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 module Psych
   ###
   # Psych::Handler is an abstract base class that defines the events used
diff --git a/lib/psych/handlers/document_stream.rb b/lib/psych/handlers/document_stream.rb
index c43b39e..67da794 100644
--- a/lib/psych/handlers/document_stream.rb
+++ b/lib/psych/handlers/document_stream.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require 'psych/tree_builder'
 
 module Psych
diff --git a/lib/psych/handlers/recorder.rb b/lib/psych/handlers/recorder.rb
index 341b81d..a8fc7b1 100644
--- a/lib/psych/handlers/recorder.rb
+++ b/lib/psych/handlers/recorder.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require 'psych/handler'
 
 module Psych
diff --git a/lib/psych/json/ruby_events.rb b/lib/psych/json/ruby_events.rb
index 478eb66..17b7ddc 100644
--- a/lib/psych/json/ruby_events.rb
+++ b/lib/psych/json/ruby_events.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 module Psych
   module JSON
     module RubyEvents # :nodoc:
diff --git a/lib/psych/json/stream.rb b/lib/psych/json/stream.rb
index 83b7e13..2ebd3d7 100644
--- a/lib/psych/json/stream.rb
+++ b/lib/psych/json/stream.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require 'psych/json/ruby_events'
 require 'psych/json/yaml_events'
 
diff --git a/lib/psych/json/tree_builder.rb b/lib/psych/json/tree_builder.rb
index 2f94b8c..5c2ee8c 100644
--- a/lib/psych/json/tree_builder.rb
+++ b/lib/psych/json/tree_builder.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require 'psych/json/yaml_events'
 
 module Psych
diff --git a/lib/psych/json/yaml_events.rb b/lib/psych/json/yaml_events.rb
index 07f6473..eb973f5 100644
--- a/lib/psych/json/yaml_events.rb
+++ b/lib/psych/json/yaml_events.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 module Psych
   module JSON
     module YAMLEvents # :nodoc:
diff --git a/lib/psych/nodes.rb b/lib/psych/nodes.rb
index 01573b5..5842c2e 100644
--- a/lib/psych/nodes.rb
+++ b/lib/psych/nodes.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require 'psych/nodes/node'
 require 'psych/nodes/stream'
 require 'psych/nodes/document'
diff --git a/lib/psych/nodes/alias.rb b/lib/psych/nodes/alias.rb
index 716a00d..8131a4b 100644
--- a/lib/psych/nodes/alias.rb
+++ b/lib/psych/nodes/alias.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 module Psych
   module Nodes
     ###
diff --git a/lib/psych/nodes/document.rb b/lib/psych/nodes/document.rb
index 7234fef..3cd418e 100644
--- a/lib/psych/nodes/document.rb
+++ b/lib/psych/nodes/document.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 module Psych
   module Nodes
     ###
diff --git a/lib/psych/nodes/mapping.rb b/lib/psych/nodes/mapping.rb
index 4c11df8..b921ddc 100644
--- a/lib/psych/nodes/mapping.rb
+++ b/lib/psych/nodes/mapping.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 module Psych
   module Nodes
     ###
diff --git a/lib/psych/nodes/node.rb b/lib/psych/nodes/node.rb
index e3621dc..1c76721 100644
--- a/lib/psych/nodes/node.rb
+++ b/lib/psych/nodes/node.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require 'stringio'
 require 'psych/class_loader'
 require 'psych/scalar_scanner'
diff --git a/lib/psych/nodes/scalar.rb b/lib/psych/nodes/scalar.rb
index ee55705..b448858 100644
--- a/lib/psych/nodes/scalar.rb
+++ b/lib/psych/nodes/scalar.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 module Psych
   module Nodes
     ###
diff --git a/lib/psych/nodes/sequence.rb b/lib/psych/nodes/sequence.rb
index 1096469..77c2c60 100644
--- a/lib/psych/nodes/sequence.rb
+++ b/lib/psych/nodes/sequence.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 module Psych
   module Nodes
     ###
diff --git a/lib/psych/nodes/stream.rb b/lib/psych/nodes/stream.rb
index 559b084..2474fe6 100644
--- a/lib/psych/nodes/stream.rb
+++ b/lib/psych/nodes/stream.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 module Psych
   module Nodes
     ###
diff --git a/lib/psych/omap.rb b/lib/psych/omap.rb
index 233b945..29cde0b 100644
--- a/lib/psych/omap.rb
+++ b/lib/psych/omap.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 module Psych
   class Omap < ::Hash
   end
diff --git a/lib/psych/parser.rb b/lib/psych/parser.rb
index 242512f..39bc828 100644
--- a/lib/psych/parser.rb
+++ b/lib/psych/parser.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 module Psych
   ###
   # YAML event parser class.  This class parses a YAML document and calls
diff --git a/lib/psych/scalar_scanner.rb b/lib/psych/scalar_scanner.rb
index 67c0cc3..29c156c 100644
--- a/lib/psych/scalar_scanner.rb
+++ b/lib/psych/scalar_scanner.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require 'strscan'
 
 module Psych
diff --git a/lib/psych/set.rb b/lib/psych/set.rb
index f35be15..760d217 100644
--- a/lib/psych/set.rb
+++ b/lib/psych/set.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 module Psych
   class Set < ::Hash
   end
diff --git a/lib/psych/stream.rb b/lib/psych/stream.rb
index 2f63d7d..24e45af 100644
--- a/lib/psych/stream.rb
+++ b/lib/psych/stream.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 module Psych
   ###
   # Psych::Stream is a streaming YAML emitter.  It will not buffer your YAML,
diff --git a/lib/psych/streaming.rb b/lib/psych/streaming.rb
index 260f8a8..eb19792 100644
--- a/lib/psych/streaming.rb
+++ b/lib/psych/streaming.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 module Psych
   module Streaming
     module ClassMethods
diff --git a/lib/psych/syntax_error.rb b/lib/psych/syntax_error.rb
index db293b9..1598e6f 100644
--- a/lib/psych/syntax_error.rb
+++ b/lib/psych/syntax_error.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require 'psych/exception'
 
 module Psych
diff --git a/lib/psych/tree_builder.rb b/lib/psych/tree_builder.rb
index d359c93..b10fd5c 100644
--- a/lib/psych/tree_builder.rb
+++ b/lib/psych/tree_builder.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require 'psych/handler'
 
 module Psych
diff --git a/lib/psych/versions.rb b/lib/psych/versions.rb
index 3d61c8b..49f8820 100644
--- a/lib/psych/versions.rb
+++ b/lib/psych/versions.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 module Psych
   # The version is Psych you're using
   VERSION = '3.0.0.beta2'
diff --git a/lib/psych/visitors.rb b/lib/psych/visitors.rb
index 5dee4eb..e2b084d 100644
--- a/lib/psych/visitors.rb
+++ b/lib/psych/visitors.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require 'psych/visitors/visitor'
 require 'psych/visitors/to_ruby'
 require 'psych/visitors/emitter'
diff --git a/lib/psych/visitors/depth_first.rb b/lib/psych/visitors/depth_first.rb
index 2d74a21..b4ff9e4 100644
--- a/lib/psych/visitors/depth_first.rb
+++ b/lib/psych/visitors/depth_first.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 module Psych
   module Visitors
     class DepthFirst < Psych::Visitors::Visitor
diff --git a/lib/psych/visitors/emitter.rb b/lib/psych/visitors/emitter.rb
index f2ff9fd..e3b92b7 100644
--- a/lib/psych/visitors/emitter.rb
+++ b/lib/psych/visitors/emitter.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 module Psych
   module Visitors
     class Emitter < Psych::Visitors::Visitor
diff --git a/lib/psych/visitors/json_tree.rb b/lib/psych/visitors/json_tree.rb
index f2f0215..9912cb1 100644
--- a/lib/psych/visitors/json_tree.rb
+++ b/lib/psych/visitors/json_tree.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require 'psych/json/ruby_events'
 
 module Psych
diff --git a/lib/psych/visitors/to_ruby.rb b/lib/psych/visitors/to_ruby.rb
index d1318b3..74a52df 100644
--- a/lib/psych/visitors/to_ruby.rb
+++ b/lib/psych/visitors/to_ruby.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require 'psych/scalar_scanner'
 require 'psych/class_loader'
 require 'psych/exception'
diff --git a/lib/psych/visitors/visitor.rb b/lib/psych/visitors/visitor.rb
index d97bf55..3f4ba64 100644
--- a/lib/psych/visitors/visitor.rb
+++ b/lib/psych/visitors/visitor.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 module Psych
   module Visitors
     class Visitor
diff --git a/lib/psych/visitors/yaml_tree.rb b/lib/psych/visitors/yaml_tree.rb
index e197a30..671bf5d 100644
--- a/lib/psych/visitors/yaml_tree.rb
+++ b/lib/psych/visitors/yaml_tree.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require 'psych/tree_builder'
 require 'psych/scalar_scanner'
 require 'psych/class_loader'
@@ -321,7 +321,7 @@ module Psych
           end
           @emitter.scalar o, nil, tag, plain, quote, style
         else
-          maptag = '!ruby/string'
+          maptag = '!ruby/string'.dup
           maptag << ":#{o.class}" unless o.class == ::String
 
           register o, @emitter.start_mapping(nil, maptag, false, Nodes::Mapping::BLOCK)
diff --git a/lib/psych/y.rb b/lib/psych/y.rb
index 82e05a7..e857953 100644
--- a/lib/psych/y.rb
+++ b/lib/psych/y.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 module Kernel
   ###
   # An alias for Psych.dump_stream meant to be used with IRB.
diff --git a/lib/psych_jars.rb b/lib/psych_jars.rb
index 2f34e34..e91e346 100644
--- a/lib/psych_jars.rb
+++ b/lib/psych_jars.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require 'psych.jar'
 
 require 'jar-dependencies'
diff --git a/psych.gemspec b/psych.gemspec
index c0ec5c5..606f518 100644
--- a/psych.gemspec
+++ b/psych.gemspec
@@ -1,4 +1,5 @@
 # -*- encoding: utf-8 -*-
+# frozen_string_literal: true
 
 Gem::Specification.new do |s|
   s.name = "psych"
diff --git a/test/psych/handlers/test_recorder.rb b/test/psych/handlers/test_recorder.rb
index 17c7c6d..d9d379e 100644
--- a/test/psych/handlers/test_recorder.rb
+++ b/test/psych/handlers/test_recorder.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require 'psych/helper'
 require 'psych/handlers/recorder'
 
diff --git a/test/psych/helper.rb b/test/psych/helper.rb
index 7b564bd..9348457 100644
--- a/test/psych/helper.rb
+++ b/test/psych/helper.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require 'minitest/autorun'
 require 'stringio'
 require 'tempfile'
diff --git a/test/psych/json/test_stream.rb b/test/psych/json/test_stream.rb
index 519c114..90a770c 100644
--- a/test/psych/json/test_stream.rb
+++ b/test/psych/json/test_stream.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require 'psych/helper'
 
 module Psych
diff --git a/test/psych/nodes/test_enumerable.rb b/test/psych/nodes/test_enumerable.rb
index 2f4e1f3..76b3685 100644
--- a/test/psych/nodes/test_enumerable.rb
+++ b/test/psych/nodes/test_enumerable.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require 'psych/helper'
 
 module Psych
diff --git a/test/psych/test_alias_and_anchor.rb b/test/psych/test_alias_and_anchor.rb
index ed00960..91c09df 100644
--- a/test/psych/test_alias_and_anchor.rb
+++ b/test/psych/test_alias_and_anchor.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require_relative 'helper'
 
 class ObjectWithInstanceVariables
diff --git a/test/psych/test_array.rb b/test/psych/test_array.rb
index 6306a04..11f5f23 100644
--- a/test/psych/test_array.rb
+++ b/test/psych/test_array.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require_relative 'helper'
 
 module Psych
diff --git a/test/psych/test_boolean.rb b/test/psych/test_boolean.rb
index b2803a6..a4b80fc 100644
--- a/test/psych/test_boolean.rb
+++ b/test/psych/test_boolean.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require_relative 'helper'
 
 module Psych
diff --git a/test/psych/test_class.rb b/test/psych/test_class.rb
index 4e1fd4a..71f7ec3 100644
--- a/test/psych/test_class.rb
+++ b/test/psych/test_class.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require_relative 'helper'
 
 module Psych
diff --git a/test/psych/test_coder.rb b/test/psych/test_coder.rb
index e578d55..5ea8cab 100644
--- a/test/psych/test_coder.rb
+++ b/test/psych/test_coder.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require_relative 'helper'
 
 module Psych
diff --git a/test/psych/test_date_time.rb b/test/psych/test_date_time.rb
index 3c8b436..f73f346 100644
--- a/test/psych/test_date_time.rb
+++ b/test/psych/test_date_time.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require_relative 'helper'
 require 'date'
 
diff --git a/test/psych/test_deprecated.rb b/test/psych/test_deprecated.rb
index eab2302..624f437 100644
--- a/test/psych/test_deprecated.rb
+++ b/test/psych/test_deprecated.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require_relative 'helper'
 
 module Psych
diff --git a/test/psych/test_document.rb b/test/psych/test_document.rb
index 97de2e1..a88dd32 100644
--- a/test/psych/test_document.rb
+++ b/test/psych/test_document.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require_relative 'helper'
 
 module Psych
diff --git a/test/psych/test_emitter.rb b/test/psych/test_emitter.rb
index 23e68b3..52d5e9d 100644
--- a/test/psych/test_emitter.rb
+++ b/test/psych/test_emitter.rb
@@ -1,5 +1,5 @@
 # -*- coding: utf-8 -*-
-# frozen_string_literal: false
+# frozen_string_literal: true
 
 require_relative 'helper'
 
@@ -7,7 +7,7 @@ module Psych
   class TestEmitter < TestCase
     def setup
       super
-      @out = StringIO.new('')
+      @out = StringIO.new(''.dup)
       @emitter = Psych::Emitter.new @out
     end
 
diff --git a/test/psych/test_encoding.rb b/test/psych/test_encoding.rb
index 13ca5db..a4f9f03 100644
--- a/test/psych/test_encoding.rb
+++ b/test/psych/test_encoding.rb
@@ -1,5 +1,5 @@
 # -*- coding: utf-8 -*-
-# frozen_string_literal: false
+# frozen_string_literal: true
 
 require_relative 'helper'
 
diff --git a/test/psych/test_exception.rb b/test/psych/test_exception.rb
index fa80fdb..3040bfb 100644
--- a/test/psych/test_exception.rb
+++ b/test/psych/test_exception.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require_relative 'helper'
 
 module Psych
diff --git a/test/psych/test_hash.rb b/test/psych/test_hash.rb
index b449ce4..e93aa73 100644
--- a/test/psych/test_hash.rb
+++ b/test/psych/test_hash.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require_relative 'helper'
 
 module Psych
diff --git a/test/psych/test_json_tree.rb b/test/psych/test_json_tree.rb
index 8bb850b..3c59a8d 100644
--- a/test/psych/test_json_tree.rb
+++ b/test/psych/test_json_tree.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require_relative 'helper'
 
 module Psych
diff --git a/test/psych/test_marshalable.rb b/test/psych/test_marshalable.rb
index 544947a..b1f4a83 100644
--- a/test/psych/test_marshalable.rb
+++ b/test/psych/test_marshalable.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require_relative 'helper'
 require 'delegate'
 
diff --git a/test/psych/test_merge_keys.rb b/test/psych/test_merge_keys.rb
index 76245ca..1bc3dd1 100644
--- a/test/psych/test_merge_keys.rb
+++ b/test/psych/test_merge_keys.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require_relative 'helper'
 
 module Psych
diff --git a/test/psych/test_nil.rb b/test/psych/test_nil.rb
index 3d4fa88..910a2e6 100644
--- a/test/psych/test_nil.rb
+++ b/test/psych/test_nil.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require_relative 'helper'
 
 module Psych
diff --git a/test/psych/test_null.rb b/test/psych/test_null.rb
index d8ccb70..9d92d74 100644
--- a/test/psych/test_null.rb
+++ b/test/psych/test_null.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require_relative 'helper'
 
 module Psych
diff --git a/test/psych/test_numeric.rb b/test/psych/test_numeric.rb
index 9d8b74f..db99a2a 100644
--- a/test/psych/test_numeric.rb
+++ b/test/psych/test_numeric.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require_relative 'helper'
 require 'bigdecimal'
 
diff --git a/test/psych/test_object.rb b/test/psych/test_object.rb
index ed1ccd9..f1c6145 100644
--- a/test/psych/test_object.rb
+++ b/test/psych/test_object.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require_relative 'helper'
 
 module Psych
diff --git a/test/psych/test_object_references.rb b/test/psych/test_object_references.rb
index 1300bfc..ca69c7d 100644
--- a/test/psych/test_object_references.rb
+++ b/test/psych/test_object_references.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require_relative 'helper'
 
 module Psych
diff --git a/test/psych/test_omap.rb b/test/psych/test_omap.rb
index 80791aa..98636de 100644
--- a/test/psych/test_omap.rb
+++ b/test/psych/test_omap.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require_relative 'helper'
 
 module Psych
diff --git a/test/psych/test_parser.rb b/test/psych/test_parser.rb
index 26aba05..6b554ce 100644
--- a/test/psych/test_parser.rb
+++ b/test/psych/test_parser.rb
@@ -1,5 +1,5 @@
 # coding: utf-8
-# frozen_string_literal: false
+# frozen_string_literal: true
 
 require_relative 'helper'
 
diff --git a/test/psych/test_psych.rb b/test/psych/test_psych.rb
index 24030d5..d0de956 100644
--- a/test/psych/test_psych.rb
+++ b/test/psych/test_psych.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require_relative 'helper'
 
 require 'stringio'
@@ -84,7 +84,7 @@ class TestPsych < Psych::TestCase
 
   def test_dump_io
     hash = {'hello' => 'TGIF!'}
-    stringio = StringIO.new ''
+    stringio = StringIO.new ''.dup
     assert_equal stringio, Psych.dump(hash, stringio)
     assert_equal Psych.dump(hash), stringio.string
   end
diff --git a/test/psych/test_safe_load.rb b/test/psych/test_safe_load.rb
index b69c54c..f3fdb9b 100644
--- a/test/psych/test_safe_load.rb
+++ b/test/psych/test_safe_load.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require 'psych/helper'
 
 module Psych
diff --git a/test/psych/test_scalar.rb b/test/psych/test_scalar.rb
index 4353ec3..4e45991 100644
--- a/test/psych/test_scalar.rb
+++ b/test/psych/test_scalar.rb
@@ -1,5 +1,5 @@
 # -*- coding: utf-8 -*-
-# frozen_string_literal: false
+# frozen_string_literal: true
 
 require_relative 'helper'
 
diff --git a/test/psych/test_scalar_scanner.rb b/test/psych/test_scalar_scanner.rb
index e51fc69..ebe8daf 100644
--- a/test/psych/test_scalar_scanner.rb
+++ b/test/psych/test_scalar_scanner.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require_relative 'helper'
 require 'date'
 
diff --git a/test/psych/test_serialize_subclasses.rb b/test/psych/test_serialize_subclasses.rb
index be209ed..8e1d0d3 100644
--- a/test/psych/test_serialize_subclasses.rb
+++ b/test/psych/test_serialize_subclasses.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require_relative 'helper'
 
 module Psych
diff --git a/test/psych/test_set.rb b/test/psych/test_set.rb
index 0eb999c..5690957 100644
--- a/test/psych/test_set.rb
+++ b/test/psych/test_set.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require_relative 'helper'
 
 module Psych
diff --git a/test/psych/test_stream.rb b/test/psych/test_stream.rb
index 1b05428..3bd557c 100644
--- a/test/psych/test_stream.rb
+++ b/test/psych/test_stream.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require_relative 'helper'
 
 module Psych
diff --git a/test/psych/test_string.rb b/test/psych/test_string.rb
index 4aa6016..7d14d16 100644
--- a/test/psych/test_string.rb
+++ b/test/psych/test_string.rb
@@ -1,5 +1,5 @@
 # encoding: UTF-8
-# frozen_string_literal: false
+# frozen_string_literal: true
 require_relative 'helper'
 
 module Psych
@@ -166,7 +166,7 @@ string: &70121654388580 !ruby/string
     end
 
     def test_nonascii_string_as_binary
-      string = "hello \x80 world!"
+      string = "hello \x80 world!".dup
       string.force_encoding 'ascii-8bit'
       yml = Psych.dump string
       assert_match(/binary/, yml)
@@ -202,7 +202,7 @@ string: &70121654388580 !ruby/string
     end
 
     def test_string_with_ivars
-      food = "is delicious"
+      food = "is delicious".dup
       ivar = "on rock and roll"
       food.instance_variable_set(:@we_built_this_city, ivar)
 
@@ -220,7 +220,7 @@ string: &70121654388580 !ruby/string
     end
 
     def binary_string percentage = 0.31, length = 100
-      string = ''
+      string = ''.dup
       (percentage * length).to_i.times do |i|
         string << "\b"
       end
diff --git a/test/psych/test_struct.rb b/test/psych/test_struct.rb
index b7968d3..721df44 100644
--- a/test/psych/test_struct.rb
+++ b/test/psych/test_struct.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require_relative 'helper'
 
 class PsychStructWithIvar < Struct.new(:foo)
diff --git a/test/psych/test_symbol.rb b/test/psych/test_symbol.rb
index a98881c..36416ff 100644
--- a/test/psych/test_symbol.rb
+++ b/test/psych/test_symbol.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require_relative 'helper'
 
 module Psych
diff --git a/test/psych/test_tainted.rb b/test/psych/test_tainted.rb
index 8705833..dcf150b 100644
--- a/test/psych/test_tainted.rb
+++ b/test/psych/test_tainted.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require_relative 'helper'
 
 module Psych
@@ -90,7 +90,7 @@ module Psych
     end
 
     def assert_taintedness string
-      @parser.parse string.taint
+      @parser.parse string.dup.taint
     end
   end
 
diff --git a/test/psych/test_tree_builder.rb b/test/psych/test_tree_builder.rb
index 09f1ee3..3e35788 100644
--- a/test/psych/test_tree_builder.rb
+++ b/test/psych/test_tree_builder.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require_relative 'helper'
 
 module Psych
diff --git a/test/psych/test_yaml.rb b/test/psych/test_yaml.rb
index cfba770..5fa759c 100644
--- a/test/psych/test_yaml.rb
+++ b/test/psych/test_yaml.rb
@@ -1,5 +1,5 @@
 # -*- coding: us-ascii; mode: ruby; ruby-indent-level: 4; tab-width: 4 -*-
-# frozen_string_literal: false
+# frozen_string_literal: true
 #												vim:sw=4:ts=4
 # $Id$
 #
diff --git a/test/psych/test_yamldbm.rb b/test/psych/test_yamldbm.rb
index 71ee04f..1f9ba15 100644
--- a/test/psych/test_yamldbm.rb
+++ b/test/psych/test_yamldbm.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require_relative 'helper'
 require 'tmpdir'
 
diff --git a/test/psych/test_yamlstore.rb b/test/psych/test_yamlstore.rb
index a9ce652..d1e927c 100644
--- a/test/psych/test_yamlstore.rb
+++ b/test/psych/test_yamlstore.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require_relative 'helper'
 require 'yaml/store'
 require 'tmpdir'
diff --git a/test/psych/visitors/test_depth_first.rb b/test/psych/visitors/test_depth_first.rb
index 8072c26..f8305e1 100644
--- a/test/psych/visitors/test_depth_first.rb
+++ b/test/psych/visitors/test_depth_first.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require 'psych/helper'
 
 module Psych
diff --git a/test/psych/visitors/test_emitter.rb b/test/psych/visitors/test_emitter.rb
index 9317855..70adbb9 100644
--- a/test/psych/visitors/test_emitter.rb
+++ b/test/psych/visitors/test_emitter.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require 'psych/helper'
 
 module Psych
diff --git a/test/psych/visitors/test_to_ruby.rb b/test/psych/visitors/test_to_ruby.rb
index 8878ea2..f342bf0 100644
--- a/test/psych/visitors/test_to_ruby.rb
+++ b/test/psych/visitors/test_to_ruby.rb
@@ -1,5 +1,5 @@
 # coding: US-ASCII
-# frozen_string_literal: false
+# frozen_string_literal: true
 require 'psych/helper'
 
 module Psych
diff --git a/test/psych/visitors/test_yaml_tree.rb b/test/psych/visitors/test_yaml_tree.rb
index 8fc18f2..503a3e4 100644
--- a/test/psych/visitors/test_yaml_tree.rb
+++ b/test/psych/visitors/test_yaml_tree.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require 'psych/helper'
 
 module Psych