diff --git a/doc/jamis.rb b/doc/jamis.rb
index c7bc84ac5..6917016e4 100644
--- a/doc/jamis.rb
+++ b/doc/jamis.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 module RDoc
 module Page
 
diff --git a/lib/rake.rb b/lib/rake.rb
index 07b03284b..68e6badf3 100644
--- a/lib/rake.rb
+++ b/lib/rake.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 #--
 # Copyright 2003-2010 by Jim Weirich (jim.weirich@gmail.com)
 #
diff --git a/lib/rake/application.rb b/lib/rake/application.rb
index e94f17290..576d0f278 100644
--- a/lib/rake/application.rb
+++ b/lib/rake/application.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require "optparse"
 
 require "rake/task_manager"
diff --git a/lib/rake/backtrace.rb b/lib/rake/backtrace.rb
index a89dd9f4d..b08c3e0c6 100644
--- a/lib/rake/backtrace.rb
+++ b/lib/rake/backtrace.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 module Rake
   module Backtrace # :nodoc: all
     SYS_KEYS  = RbConfig::CONFIG.keys.grep(/(?:[a-z]prefix|libdir)\z/)
diff --git a/lib/rake/clean.rb b/lib/rake/clean.rb
index f66353a0a..92e2025e7 100644
--- a/lib/rake/clean.rb
+++ b/lib/rake/clean.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 # The 'rake/clean' file defines two file lists (CLEAN and CLOBBER) and
 # two rake tasks (:clean and :clobber).
 #
diff --git a/lib/rake/cloneable.rb b/lib/rake/cloneable.rb
index d53645f2f..37dd6d9e2 100644
--- a/lib/rake/cloneable.rb
+++ b/lib/rake/cloneable.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 module Rake
   ##
   # Mixin for creating easily cloned objects.
diff --git a/lib/rake/cpu_counter.rb b/lib/rake/cpu_counter.rb
index 82a5eb8aa..369e1a41f 100644
--- a/lib/rake/cpu_counter.rb
+++ b/lib/rake/cpu_counter.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 module Rake
 
   # Based on a script at:
diff --git a/lib/rake/default_loader.rb b/lib/rake/default_loader.rb
index 6154408f4..2d1115e20 100644
--- a/lib/rake/default_loader.rb
+++ b/lib/rake/default_loader.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 module Rake
 
   # Default Rakefile loader used by +import+.
diff --git a/lib/rake/dsl_definition.rb b/lib/rake/dsl_definition.rb
index c52bd601f..203dc0b17 100644
--- a/lib/rake/dsl_definition.rb
+++ b/lib/rake/dsl_definition.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 # Rake DSL functions.
 require "rake/file_utils_ext"
 
diff --git a/lib/rake/early_time.rb b/lib/rake/early_time.rb
index abcb1872b..6c6919135 100644
--- a/lib/rake/early_time.rb
+++ b/lib/rake/early_time.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 module Rake
 
   # EarlyTime is a fake timestamp that occurs _before_ any other time value.
diff --git a/lib/rake/ext/core.rb b/lib/rake/ext/core.rb
index 7575df15a..82ad823bf 100644
--- a/lib/rake/ext/core.rb
+++ b/lib/rake/ext/core.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 class Module
   # Check for an existing method in the current class before extending.  If
   # the method already exists, then a warning is printed and the extension is
diff --git a/lib/rake/ext/string.rb b/lib/rake/ext/string.rb
index 37764c845..1020de5f9 100644
--- a/lib/rake/ext/string.rb
+++ b/lib/rake/ext/string.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require "rake/ext/core"
 
 class String
diff --git a/lib/rake/file_creation_task.rb b/lib/rake/file_creation_task.rb
index f3c5c78a1..a3bf78b0e 100644
--- a/lib/rake/file_creation_task.rb
+++ b/lib/rake/file_creation_task.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require "rake/file_task"
 require "rake/early_time"
 
diff --git a/lib/rake/file_list.rb b/lib/rake/file_list.rb
index a30c6338c..6928333ff 100644
--- a/lib/rake/file_list.rb
+++ b/lib/rake/file_list.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require "rake/cloneable"
 require "rake/file_utils_ext"
 require "rake/ext/string"
diff --git a/lib/rake/file_task.rb b/lib/rake/file_task.rb
index cbb978e7f..1f64530ff 100644
--- a/lib/rake/file_task.rb
+++ b/lib/rake/file_task.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require "rake/task.rb"
 require "rake/early_time"
 
diff --git a/lib/rake/file_utils.rb b/lib/rake/file_utils.rb
index 3e56710e2..764c10d29 100644
--- a/lib/rake/file_utils.rb
+++ b/lib/rake/file_utils.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require "rbconfig"
 require "fileutils"
 
diff --git a/lib/rake/file_utils_ext.rb b/lib/rake/file_utils_ext.rb
index e5930d4ab..b3ea9b9a4 100644
--- a/lib/rake/file_utils_ext.rb
+++ b/lib/rake/file_utils_ext.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require "rake/file_utils"
 
 module Rake
diff --git a/lib/rake/invocation_chain.rb b/lib/rake/invocation_chain.rb
index 540628957..84a19b1f5 100644
--- a/lib/rake/invocation_chain.rb
+++ b/lib/rake/invocation_chain.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 module Rake
 
   # InvocationChain tracks the chain of task invocations to detect
diff --git a/lib/rake/invocation_exception_mixin.rb b/lib/rake/invocation_exception_mixin.rb
index 84ff3353b..c252361b2 100644
--- a/lib/rake/invocation_exception_mixin.rb
+++ b/lib/rake/invocation_exception_mixin.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 module Rake
   module InvocationExceptionMixin
     # Return the invocation chain (list of Rake tasks) that were in
diff --git a/lib/rake/late_time.rb b/lib/rake/late_time.rb
index d1d9470ec..39d00c10b 100644
--- a/lib/rake/late_time.rb
+++ b/lib/rake/late_time.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 module Rake
   # LateTime is a fake timestamp that occurs _after_ any other time value.
   class LateTime
diff --git a/lib/rake/linked_list.rb b/lib/rake/linked_list.rb
index 54d0c1287..32aa79bfd 100644
--- a/lib/rake/linked_list.rb
+++ b/lib/rake/linked_list.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 module Rake
 
   # Polylithic linked list structure used to implement several data
diff --git a/lib/rake/loaders/makefile.rb b/lib/rake/loaders/makefile.rb
index d0436bb79..f1be393d6 100644
--- a/lib/rake/loaders/makefile.rb
+++ b/lib/rake/loaders/makefile.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 module Rake
 
   # Makefile loader to be used with the import file loader.  Use this to
diff --git a/lib/rake/multi_task.rb b/lib/rake/multi_task.rb
index 7118dc411..60480b240 100644
--- a/lib/rake/multi_task.rb
+++ b/lib/rake/multi_task.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 module Rake
 
   # Same as a regular task, but the immediate prerequisites are done in
diff --git a/lib/rake/name_space.rb b/lib/rake/name_space.rb
index 0d7eb80b6..39b376fd6 100644
--- a/lib/rake/name_space.rb
+++ b/lib/rake/name_space.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 ##
 # The NameSpace class will lookup task names in the scope defined by a
 # +namespace+ command.
diff --git a/lib/rake/packagetask.rb b/lib/rake/packagetask.rb
index 034b8e9e8..b7c96b32b 100644
--- a/lib/rake/packagetask.rb
+++ b/lib/rake/packagetask.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 # Define a package task library to aid in the definition of
 # redistributable package files.
 
diff --git a/lib/rake/phony.rb b/lib/rake/phony.rb
index a172f9c60..aac793a42 100644
--- a/lib/rake/phony.rb
+++ b/lib/rake/phony.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 # Defines a :phony task that you can use as a dependency. This allows
 # file-based tasks to use non-file-based tasks as prerequisites
 # without forcing them to rebuild.
diff --git a/lib/rake/private_reader.rb b/lib/rake/private_reader.rb
index 162097857..121b105c1 100644
--- a/lib/rake/private_reader.rb
+++ b/lib/rake/private_reader.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 module Rake
 
   # Include PrivateReader to use +private_reader+.
diff --git a/lib/rake/promise.rb b/lib/rake/promise.rb
index 37221e427..c5f2b3f10 100644
--- a/lib/rake/promise.rb
+++ b/lib/rake/promise.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 module Rake
 
   # A Promise object represents a promise to do work (a chore) in the
diff --git a/lib/rake/pseudo_status.rb b/lib/rake/pseudo_status.rb
index 16e1903bd..f5f4fe991 100644
--- a/lib/rake/pseudo_status.rb
+++ b/lib/rake/pseudo_status.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 module Rake
 
   ##
diff --git a/lib/rake/rake_module.rb b/lib/rake/rake_module.rb
index 75feb1261..bb97ec5cd 100644
--- a/lib/rake/rake_module.rb
+++ b/lib/rake/rake_module.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require "rake/application"
 
 module Rake
diff --git a/lib/rake/rake_test_loader.rb b/lib/rake/rake_test_loader.rb
index 98dcced06..88b5cacdc 100644
--- a/lib/rake/rake_test_loader.rb
+++ b/lib/rake/rake_test_loader.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require "rake"
 
 # Load the test files from the command line.
diff --git a/lib/rake/rule_recursion_overflow_error.rb b/lib/rake/rule_recursion_overflow_error.rb
index 39d44aac6..7a5eab0ae 100644
--- a/lib/rake/rule_recursion_overflow_error.rb
+++ b/lib/rake/rule_recursion_overflow_error.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 module Rake
 
   # Error indicating a recursion overflow error in task selection.
diff --git a/lib/rake/scope.rb b/lib/rake/scope.rb
index b432f5f29..540219c7a 100644
--- a/lib/rake/scope.rb
+++ b/lib/rake/scope.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 module Rake
   class Scope < LinkedList # :nodoc: all
 
diff --git a/lib/rake/task.rb b/lib/rake/task.rb
index 23faf96e5..dc7066466 100644
--- a/lib/rake/task.rb
+++ b/lib/rake/task.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require "rake/invocation_exception_mixin"
 
 module Rake
diff --git a/lib/rake/task_argument_error.rb b/lib/rake/task_argument_error.rb
index 3e1dda64d..277b8b9c7 100644
--- a/lib/rake/task_argument_error.rb
+++ b/lib/rake/task_argument_error.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 module Rake
 
   # Error indicating an ill-formed task declaration.
diff --git a/lib/rake/task_arguments.rb b/lib/rake/task_arguments.rb
index c98057c8f..885d76909 100644
--- a/lib/rake/task_arguments.rb
+++ b/lib/rake/task_arguments.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 module Rake
 
   ##
diff --git a/lib/rake/task_manager.rb b/lib/rake/task_manager.rb
index 971984ca5..4e59b63f0 100644
--- a/lib/rake/task_manager.rb
+++ b/lib/rake/task_manager.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 module Rake
 
   # The TaskManager module is a mixin for managing tasks.
diff --git a/lib/rake/tasklib.rb b/lib/rake/tasklib.rb
index 7bcda1789..7a25d0839 100644
--- a/lib/rake/tasklib.rb
+++ b/lib/rake/tasklib.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require "rake"
 
 module Rake
diff --git a/lib/rake/testtask.rb b/lib/rake/testtask.rb
index bb7f0ee8a..4986e0c9f 100644
--- a/lib/rake/testtask.rb
+++ b/lib/rake/testtask.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require "rake"
 require "rake/tasklib"
 
diff --git a/lib/rake/thread_history_display.rb b/lib/rake/thread_history_display.rb
index 04273541e..2d04e4c98 100644
--- a/lib/rake/thread_history_display.rb
+++ b/lib/rake/thread_history_display.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require "rake/private_reader"
 
 module Rake
diff --git a/lib/rake/thread_pool.rb b/lib/rake/thread_pool.rb
index 1c2f5f50f..43ac9f358 100644
--- a/lib/rake/thread_pool.rb
+++ b/lib/rake/thread_pool.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require "set"
 
 require "rake/promise"
diff --git a/lib/rake/trace_output.rb b/lib/rake/trace_output.rb
index c740b9e23..319ee4471 100644
--- a/lib/rake/trace_output.rb
+++ b/lib/rake/trace_output.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 module Rake
   module TraceOutput # :nodoc: all
 
diff --git a/lib/rake/version.rb b/lib/rake/version.rb
index 1908ff855..f9a0169df 100644
--- a/lib/rake/version.rb
+++ b/lib/rake/version.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 module Rake
   VERSION = "12.0.0"
 
diff --git a/lib/rake/win32.rb b/lib/rake/win32.rb
index 1fc02a5ae..94f6935d0 100644
--- a/lib/rake/win32.rb
+++ b/lib/rake/win32.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require "rbconfig"
 
 module Rake
diff --git a/test/helper.rb b/test/helper.rb
index 532745319..0c3afc92d 100644
--- a/test/helper.rb
+++ b/test/helper.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 $:.unshift File.expand_path("../../lib", __FILE__)
 
 require 'coveralls'
diff --git a/test/support/file_creation.rb b/test/support/file_creation.rb
index facc57a03..7631fa663 100644
--- a/test/support/file_creation.rb
+++ b/test/support/file_creation.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 module FileCreation
   OLDFILE = "old"
   NEWFILE = "new"
diff --git a/test/support/rakefile_definitions.rb b/test/support/rakefile_definitions.rb
index 9a19d43fc..8632b8d7d 100644
--- a/test/support/rakefile_definitions.rb
+++ b/test/support/rakefile_definitions.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 module RakefileDefinitions
   include FileUtils
 
diff --git a/test/support/ruby_runner.rb b/test/support/ruby_runner.rb
index 199f60dd6..60d48abfe 100644
--- a/test/support/ruby_runner.rb
+++ b/test/support/ruby_runner.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 module RubyRunner
   include FileUtils
 
diff --git a/test/test_private_reader.rb b/test/test_private_reader.rb
index 56160f062..7fdbf17b5 100644
--- a/test/test_private_reader.rb
+++ b/test/test_private_reader.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require File.expand_path("../helper", __FILE__)
 require "rake/private_reader"
 
diff --git a/test/test_rake.rb b/test/test_rake.rb
index dfbb7d232..61fec24f7 100644
--- a/test/test_rake.rb
+++ b/test/test_rake.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require File.expand_path("../helper", __FILE__)
 
 class TestRake < Rake::TestCase
diff --git a/test/test_rake_application.rb b/test/test_rake_application.rb
index cd8feebbc..9dc140c3b 100644
--- a/test/test_rake_application.rb
+++ b/test/test_rake_application.rb
@@ -1,4 +1,4 @@
-#encoding: UTF-8
+# frozen_string_literal: false
 require File.expand_path("../helper", __FILE__)
 
 class TestRakeApplication < Rake::TestCase
diff --git a/test/test_rake_application_options.rb b/test/test_rake_application_options.rb
index 149d8dcfd..466bb2beb 100644
--- a/test/test_rake_application_options.rb
+++ b/test/test_rake_application_options.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require File.expand_path("../helper", __FILE__)
 
 TESTING_REQUIRE = []
diff --git a/test/test_rake_backtrace.rb b/test/test_rake_backtrace.rb
index ec727a292..60aed4658 100644
--- a/test/test_rake_backtrace.rb
+++ b/test/test_rake_backtrace.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require File.expand_path("../helper", __FILE__)
 require "open3"
 
diff --git a/test/test_rake_clean.rb b/test/test_rake_clean.rb
index 5439a415f..d4f0dae67 100644
--- a/test/test_rake_clean.rb
+++ b/test/test_rake_clean.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require File.expand_path("../helper", __FILE__)
 require "rake/clean"
 
diff --git a/test/test_rake_cpu_counter.rb b/test/test_rake_cpu_counter.rb
index aac16b2d7..a55b5731d 100644
--- a/test/test_rake_cpu_counter.rb
+++ b/test/test_rake_cpu_counter.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require File.expand_path("../helper", __FILE__)
 
 class TestRakeCpuCounter < Rake::TestCase
diff --git a/test/test_rake_definitions.rb b/test/test_rake_definitions.rb
index 464cc6309..86517b1cd 100644
--- a/test/test_rake_definitions.rb
+++ b/test/test_rake_definitions.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require File.expand_path("../helper", __FILE__)
 require "fileutils"
 
diff --git a/test/test_rake_directory_task.rb b/test/test_rake_directory_task.rb
index e42bd9c77..3121f7b6e 100644
--- a/test/test_rake_directory_task.rb
+++ b/test/test_rake_directory_task.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require File.expand_path("../helper", __FILE__)
 require "fileutils"
 require "pathname"
diff --git a/test/test_rake_dsl.rb b/test/test_rake_dsl.rb
index 7f82c6afa..d105c4755 100644
--- a/test/test_rake_dsl.rb
+++ b/test/test_rake_dsl.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require File.expand_path("../helper", __FILE__)
 
 class TestRakeDsl < Rake::TestCase
diff --git a/test/test_rake_early_time.rb b/test/test_rake_early_time.rb
index 71ee3e157..39a9eadf3 100644
--- a/test/test_rake_early_time.rb
+++ b/test/test_rake_early_time.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require File.expand_path("../helper", __FILE__)
 
 class TestRakeEarlyTime < Rake::TestCase
diff --git a/test/test_rake_extension.rb b/test/test_rake_extension.rb
index 293ec1304..dafa291c1 100644
--- a/test/test_rake_extension.rb
+++ b/test/test_rake_extension.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require File.expand_path("../helper", __FILE__)
 require "stringio"
 
diff --git a/test/test_rake_file_creation_task.rb b/test/test_rake_file_creation_task.rb
index 35f843e9e..e4f1c1253 100644
--- a/test/test_rake_file_creation_task.rb
+++ b/test/test_rake_file_creation_task.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require File.expand_path("../helper", __FILE__)
 require "fileutils"
 
diff --git a/test/test_rake_file_list.rb b/test/test_rake_file_list.rb
index 32ca7a8e3..f220e07f6 100644
--- a/test/test_rake_file_list.rb
+++ b/test/test_rake_file_list.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require File.expand_path("../helper", __FILE__)
 require "pathname"
 
diff --git a/test/test_rake_file_list_path_map.rb b/test/test_rake_file_list_path_map.rb
index 28953a97a..46f59273e 100644
--- a/test/test_rake_file_list_path_map.rb
+++ b/test/test_rake_file_list_path_map.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require File.expand_path("../helper", __FILE__)
 
 class TestRakeFileListPathMap < Rake::TestCase
diff --git a/test/test_rake_file_task.rb b/test/test_rake_file_task.rb
index 24614dabe..74840d308 100644
--- a/test/test_rake_file_task.rb
+++ b/test/test_rake_file_task.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require File.expand_path("../helper", __FILE__)
 require "fileutils"
 require "pathname"
diff --git a/test/test_rake_file_utils.rb b/test/test_rake_file_utils.rb
index 00ef76e41..39d4dff61 100644
--- a/test/test_rake_file_utils.rb
+++ b/test/test_rake_file_utils.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require File.expand_path("../helper", __FILE__)
 require "fileutils"
 require "stringio"
diff --git a/test/test_rake_functional.rb b/test/test_rake_functional.rb
index 3496bc12d..e6e010b5f 100644
--- a/test/test_rake_functional.rb
+++ b/test/test_rake_functional.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require File.expand_path("../helper", __FILE__)
 require "fileutils"
 require "open3"
diff --git a/test/test_rake_invocation_chain.rb b/test/test_rake_invocation_chain.rb
index ba5f8724f..61eba3487 100644
--- a/test/test_rake_invocation_chain.rb
+++ b/test/test_rake_invocation_chain.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require File.expand_path("../helper", __FILE__)
 
 class TestRakeInvocationChain < Rake::TestCase
diff --git a/test/test_rake_late_time.rb b/test/test_rake_late_time.rb
index a88826da7..1641da61d 100644
--- a/test/test_rake_late_time.rb
+++ b/test/test_rake_late_time.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require File.expand_path("../helper", __FILE__)
 
 class TestRakeLateTime < Rake::TestCase
diff --git a/test/test_rake_linked_list.rb b/test/test_rake_linked_list.rb
index a3c4d1972..975befc73 100644
--- a/test/test_rake_linked_list.rb
+++ b/test/test_rake_linked_list.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require File.expand_path("../helper", __FILE__)
 
 class TestLinkedList < Rake::TestCase
diff --git a/test/test_rake_makefile_loader.rb b/test/test_rake_makefile_loader.rb
index bd70fd3b6..42ce0f604 100644
--- a/test/test_rake_makefile_loader.rb
+++ b/test/test_rake_makefile_loader.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require File.expand_path("../helper", __FILE__)
 require "rake/loaders/makefile"
 
diff --git a/test/test_rake_multi_task.rb b/test/test_rake_multi_task.rb
index bab25b158..c614e15af 100644
--- a/test/test_rake_multi_task.rb
+++ b/test/test_rake_multi_task.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require File.expand_path("../helper", __FILE__)
 require "thread"
 
diff --git a/test/test_rake_name_space.rb b/test/test_rake_name_space.rb
index e043c07fa..274d71c4c 100644
--- a/test/test_rake_name_space.rb
+++ b/test/test_rake_name_space.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require File.expand_path("../helper", __FILE__)
 
 class TestRakeNameSpace < Rake::TestCase
diff --git a/test/test_rake_package_task.rb b/test/test_rake_package_task.rb
index 7bacb7a52..a3ce632ec 100644
--- a/test/test_rake_package_task.rb
+++ b/test/test_rake_package_task.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require File.expand_path("../helper", __FILE__)
 require "rake/packagetask"
 
diff --git a/test/test_rake_path_map.rb b/test/test_rake_path_map.rb
index 040692930..1f20ad27b 100644
--- a/test/test_rake_path_map.rb
+++ b/test/test_rake_path_map.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require File.expand_path("../helper", __FILE__)
 
 class TestRakePathMap < Rake::TestCase
diff --git a/test/test_rake_path_map_explode.rb b/test/test_rake_path_map_explode.rb
index 554a02266..18f85a11b 100644
--- a/test/test_rake_path_map_explode.rb
+++ b/test/test_rake_path_map_explode.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require File.expand_path("../helper", __FILE__)
 
 class TestRakePathMapExplode < Rake::TestCase
diff --git a/test/test_rake_path_map_partial.rb b/test/test_rake_path_map_partial.rb
index 0adc24313..c62694545 100644
--- a/test/test_rake_path_map_partial.rb
+++ b/test/test_rake_path_map_partial.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require File.expand_path("../helper", __FILE__)
 
 class TestRakePathMapPartial < Rake::TestCase
diff --git a/test/test_rake_pseudo_status.rb b/test/test_rake_pseudo_status.rb
index d9fe42216..9c8c3bee3 100644
--- a/test/test_rake_pseudo_status.rb
+++ b/test/test_rake_pseudo_status.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require File.expand_path("../helper", __FILE__)
 
 class TestRakePseudoStatus < Rake::TestCase
diff --git a/test/test_rake_rake_test_loader.rb b/test/test_rake_rake_test_loader.rb
index 855606d4d..4c84c1bd8 100644
--- a/test/test_rake_rake_test_loader.rb
+++ b/test/test_rake_rake_test_loader.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require File.expand_path("../helper", __FILE__)
 
 class TestRakeRakeTestLoader < Rake::TestCase
diff --git a/test/test_rake_reduce_compat.rb b/test/test_rake_reduce_compat.rb
index de81b474b..71aeabd62 100644
--- a/test/test_rake_reduce_compat.rb
+++ b/test/test_rake_reduce_compat.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require File.expand_path("../helper", __FILE__)
 require "open3"
 
diff --git a/test/test_rake_require.rb b/test/test_rake_require.rb
index c77344cc3..8b8757f64 100644
--- a/test/test_rake_require.rb
+++ b/test/test_rake_require.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require File.expand_path("../helper", __FILE__)
 
 class TestRakeRequire < Rake::TestCase
diff --git a/test/test_rake_rules.rb b/test/test_rake_rules.rb
index 35f0b45db..2e4f341e5 100644
--- a/test/test_rake_rules.rb
+++ b/test/test_rake_rules.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require File.expand_path("../helper", __FILE__)
 require "fileutils"
 
diff --git a/test/test_rake_scope.rb b/test/test_rake_scope.rb
index 169c0d9f9..54a32e07a 100644
--- a/test/test_rake_scope.rb
+++ b/test/test_rake_scope.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require File.expand_path("../helper", __FILE__)
 
 class TestRakeScope < Rake::TestCase
diff --git a/test/test_rake_task.rb b/test/test_rake_task.rb
index 5f5a63e30..b1952db1f 100644
--- a/test/test_rake_task.rb
+++ b/test/test_rake_task.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require File.expand_path("../helper", __FILE__)
 require "fileutils"
 
diff --git a/test/test_rake_task_argument_parsing.rb b/test/test_rake_task_argument_parsing.rb
index 4bc0ff0ae..684de7e27 100644
--- a/test/test_rake_task_argument_parsing.rb
+++ b/test/test_rake_task_argument_parsing.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require File.expand_path("../helper", __FILE__)
 
 class TestRakeTaskArgumentParsing < Rake::TestCase
diff --git a/test/test_rake_task_arguments.rb b/test/test_rake_task_arguments.rb
index 383d4a172..77d5deb05 100644
--- a/test/test_rake_task_arguments.rb
+++ b/test/test_rake_task_arguments.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require File.expand_path("../helper", __FILE__)
 
 class TestRakeTaskArguments < Rake::TestCase
diff --git a/test/test_rake_task_manager.rb b/test/test_rake_task_manager.rb
index a611bd737..d7b3ae669 100644
--- a/test/test_rake_task_manager.rb
+++ b/test/test_rake_task_manager.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require File.expand_path("../helper", __FILE__)
 
 class TestRakeTaskManager < Rake::TestCase
diff --git a/test/test_rake_task_manager_argument_resolution.rb b/test/test_rake_task_manager_argument_resolution.rb
index 6d292816d..ee0b77f9a 100644
--- a/test/test_rake_task_manager_argument_resolution.rb
+++ b/test/test_rake_task_manager_argument_resolution.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require File.expand_path("../helper", __FILE__)
 
 class TestRakeTaskManagerArgumentResolution < Rake::TestCase
diff --git a/test/test_rake_task_with_arguments.rb b/test/test_rake_task_with_arguments.rb
index 5f71b6b1a..cf359daca 100644
--- a/test/test_rake_task_with_arguments.rb
+++ b/test/test_rake_task_with_arguments.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require File.expand_path("../helper", __FILE__)
 
 class TestRakeTaskWithArguments < Rake::TestCase
diff --git a/test/test_rake_test_task.rb b/test/test_rake_test_task.rb
index 8e422f164..76e69982d 100644
--- a/test/test_rake_test_task.rb
+++ b/test/test_rake_test_task.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require File.expand_path("../helper", __FILE__)
 require "rake/testtask"
 
diff --git a/test/test_rake_thread_pool.rb b/test/test_rake_thread_pool.rb
index d365574ba..8314ac553 100644
--- a/test/test_rake_thread_pool.rb
+++ b/test/test_rake_thread_pool.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require File.expand_path("../helper", __FILE__)
 require "rake/thread_pool"
 
diff --git a/test/test_rake_top_level_functions.rb b/test/test_rake_top_level_functions.rb
index a3bb2fbb8..7082caad7 100644
--- a/test/test_rake_top_level_functions.rb
+++ b/test/test_rake_top_level_functions.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require File.expand_path("../helper", __FILE__)
 
 class TestRakeTopLevelFunctions < Rake::TestCase
diff --git a/test/test_rake_win32.rb b/test/test_rake_win32.rb
index be95adb92..15f6663c9 100644
--- a/test/test_rake_win32.rb
+++ b/test/test_rake_win32.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require File.expand_path("../helper", __FILE__)
 
 class TestRakeWin32 < Rake::TestCase
diff --git a/test/test_thread_history_display.rb b/test/test_thread_history_display.rb
index f3466cef7..304471e71 100644
--- a/test/test_thread_history_display.rb
+++ b/test/test_thread_history_display.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require File.expand_path("../helper", __FILE__)
 
 require "rake/thread_history_display"
diff --git a/test/test_trace_output.rb b/test/test_trace_output.rb
index 18d2eee0f..a55296f7f 100644
--- a/test/test_trace_output.rb
+++ b/test/test_trace_output.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require File.expand_path("../helper", __FILE__)
 require "stringio"