13 files changed, 13 insertions, 0 deletions
diff --git a/test/mkmf/base.rb b/test/mkmf/base.rb
index d8e2a04fe7..86bdd29286 100644
--- a/test/mkmf/base.rb
+++ b/test/mkmf/base.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 $extmk = true
 
 require 'test/unit'
diff --git a/test/mkmf/test_config.rb b/test/mkmf/test_config.rb
index 7bf537e693..07ed641415 100644
--- a/test/mkmf/test_config.rb
+++ b/test/mkmf/test_config.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 $extmk = true
 
 require 'test/unit'
diff --git a/test/mkmf/test_constant.rb b/test/mkmf/test_constant.rb
index fd1f940c44..f5a87a1caa 100644
--- a/test/mkmf/test_constant.rb
+++ b/test/mkmf/test_constant.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require_relative 'base'
 
 class TestMkmf
diff --git a/test/mkmf/test_convertible.rb b/test/mkmf/test_convertible.rb
index eec2d12c66..1baf892842 100644
--- a/test/mkmf/test_convertible.rb
+++ b/test/mkmf/test_convertible.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require_relative 'base'
 
 class TestMkmf
diff --git a/test/mkmf/test_find_executable.rb b/test/mkmf/test_find_executable.rb
index fe45ef2d1c..d2b460bd00 100644
--- a/test/mkmf/test_find_executable.rb
+++ b/test/mkmf/test_find_executable.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require_relative 'base'
 
 class TestMkmf
diff --git a/test/mkmf/test_flags.rb b/test/mkmf/test_flags.rb
index e49d474dc9..69a1084608 100644
--- a/test/mkmf/test_flags.rb
+++ b/test/mkmf/test_flags.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require_relative 'base'
 
 class TestMkmf
diff --git a/test/mkmf/test_framework.rb b/test/mkmf/test_framework.rb
index 70ea8c3327..ae05b0cffc 100644
--- a/test/mkmf/test_framework.rb
+++ b/test/mkmf/test_framework.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require_relative 'base'
 
 class TestMkmf
diff --git a/test/mkmf/test_have_func.rb b/test/mkmf/test_have_func.rb
index 8049ffba18..5f76b72122 100644
--- a/test/mkmf/test_have_func.rb
+++ b/test/mkmf/test_have_func.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require_relative 'base'
 require 'tempfile'
 
diff --git a/test/mkmf/test_have_library.rb b/test/mkmf/test_have_library.rb
index bf17b85f61..bb9ce6972d 100644
--- a/test/mkmf/test_have_library.rb
+++ b/test/mkmf/test_have_library.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require_relative 'base'
 require 'tempfile'
 
diff --git a/test/mkmf/test_have_macro.rb b/test/mkmf/test_have_macro.rb
index 43c4029f70..ebc5648097 100644
--- a/test/mkmf/test_have_macro.rb
+++ b/test/mkmf/test_have_macro.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require_relative 'base'
 require 'tempfile'
 
diff --git a/test/mkmf/test_libs.rb b/test/mkmf/test_libs.rb
index 27674dfd26..bb65e4de90 100644
--- a/test/mkmf/test_libs.rb
+++ b/test/mkmf/test_libs.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require_relative 'base'
 
 class TestMkmf
diff --git a/test/mkmf/test_signedness.rb b/test/mkmf/test_signedness.rb
index 8d58073698..589dcb56e8 100644
--- a/test/mkmf/test_signedness.rb
+++ b/test/mkmf/test_signedness.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require_relative 'base'
 
 class TestMkmf
diff --git a/test/mkmf/test_sizeof.rb b/test/mkmf/test_sizeof.rb
index c0144226d5..742c3d6454 100644
--- a/test/mkmf/test_sizeof.rb
+++ b/test/mkmf/test_sizeof.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: false
 require_relative 'base'
 
 class TestMkmf