5 files changed, 5 insertions, 0 deletions
diff --git a/test/testunit/tests_for_parallel/ptest_first.rb b/test/testunit/tests_for_parallel/ptest_first.rb
index 66c7704a45..f8687335b5 100644
--- a/test/testunit/tests_for_parallel/ptest_first.rb
+++ b/test/testunit/tests_for_parallel/ptest_first.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require 'test/unit'
 
 class TestA < Test::Unit::TestCase
diff --git a/test/testunit/tests_for_parallel/ptest_forth.rb b/test/testunit/tests_for_parallel/ptest_forth.rb
index 46c88da519..8831676e19 100644
--- a/test/testunit/tests_for_parallel/ptest_forth.rb
+++ b/test/testunit/tests_for_parallel/ptest_forth.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require 'test/unit'
 
 class TestE < Test::Unit::TestCase
diff --git a/test/testunit/tests_for_parallel/ptest_second.rb b/test/testunit/tests_for_parallel/ptest_second.rb
index 7004d68493..a793c17eb3 100644
--- a/test/testunit/tests_for_parallel/ptest_second.rb
+++ b/test/testunit/tests_for_parallel/ptest_second.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require 'test/unit'
 
 class TestB < Test::Unit::TestCase
diff --git a/test/testunit/tests_for_parallel/ptest_third.rb b/test/testunit/tests_for_parallel/ptest_third.rb
index 338fc32a91..3f448ecfc1 100644
--- a/test/testunit/tests_for_parallel/ptest_third.rb
+++ b/test/testunit/tests_for_parallel/ptest_third.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require 'test/unit'
 
 class TestD < Test::Unit::TestCase
diff --git a/test/testunit/tests_for_parallel/runner.rb b/test/testunit/tests_for_parallel/runner.rb
index e262e1e6c7..bece739917 100644
--- a/test/testunit/tests_for_parallel/runner.rb
+++ b/test/testunit/tests_for_parallel/runner.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require 'rbconfig'
 
 $LOAD_PATH.unshift "#{File.dirname(__FILE__)}/../../lib"