Merge branch 'v1.8'

1 files changed, 15 insertions, 0 deletions

diff --git a/tests/json_generator_test.rb b/tests/json_generator_test.rb
index 7e487d8..2bb7e15 100644
--- a/tests/json_generator_test.rb
+++ b/tests/json_generator_test.rb
@@ -1,3 +1,7 @@
+#!/usr/bin/env ruby
+# encoding: utf-8
+# frozen_string_literal: false
+
 require 'test_helper'
 
 class JSONGeneratorTest < Test::Unit::TestCase
@@ -362,4 +366,15 @@ EOT
     json = '["\\\'"]'
     assert_equal '["\'"]', generate(data)
   end
+
+  def test_string_subclass
+    s = Class.new(String) do
+      def to_s; self; end
+      undef to_json
+    end
+    assert_nothing_raised(SystemStackError) do
+      assert_equal '["foo"]', JSON.generate([s.new('foo')])
+    end
+
+  end
 end