    def test_funcall_notimplement
      bug3662 = '[ruby-dev:41953]'
      assert_raise(NotImplementedError, bug3662) {
+diff --git a/test/erb/test_erb.rb b/test/erb/test_erb.rb
+index 6a6ce3d129..665d1e2933 100644
+--- a/test/erb/test_erb.rb
++++ b/test/erb/test_erb.rb
+@@ -2,6 +2,7 @@
+ # frozen_string_literal: false
+ require 'test/unit'
+ require 'erb'
++require 'stringio'
+ 
+ class TestERB < Test::Unit::TestCase
+   class MyError < RuntimeError ; end
+@@ -235,6 +236,7 @@ def test_run
+     $stdout = orig
+     out.rewind
+     assert_equal('9', out.read)
++    return unless num               # to remove warning
+   end
+ 
+   class Foo; end
 diff --git a/test/erb/test_erb_m17n.rb b/test/erb/test_erb_m17n.rb
 index a7840c9605..2fd9e700f3 100644
 --- a/test/erb/test_erb_m17n.rb

     DOC = <<END
 <paper>
 <title>Remove this element and figs order differently</title>

 
   FileUtils::METHODS.each do |m|
     define_method "test_singleton_visibility_#{m}" do
diff --git a/test/optparse/test_zsh_completion.rb b/test/optparse/test_zsh_completion.rb
index 1bc6c7f0bb..8411bc41d4 100644
--- a/test/optparse/test_zsh_completion.rb
+++ b/test/optparse/test_zsh_completion.rb
@@ -4,7 +4,7 @@
 
 class TestOptionParser < Test::Unit::TestCase
 end
-class TestOptionParser::BashCompletion < Test::Unit::TestCase
+class TestOptionParser::BashCompletionZSH < Test::Unit::TestCase
   def setup
     @opt = OptionParser.new
     @opt.define("-z", "zzz") {}
diff --git a/test/rexml/test_martin_fowler.rb b/test/rexml/test_martin_fowler.rb
index da685a80ec..add3c82723 100644
--- a/test/rexml/test_martin_fowler.rb
