add timeout.

* test/ruby/test_trace.rb (test_trace_stackoverflow): sometimes this test
  was stopped forever and killed by test process forcibly. However, this
  test only checks if this code cause some critical failure such as SEGV.
  So that we can add timeout for this code.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@58482 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

test/ruby/test_trace.rb

@@ -63,6 +63,7 @@ class TestTrace < Test::Unit::TestCase
   def test_trace_stackoverflow
     assert_normal_exit("#{<<-"begin;"}\n#{<<~"end;"}", timeout: 60)
     begin;
+      require 'timeout'
       require 'tracer'
       class HogeError < StandardError
         def to_s
@@ -70,8 +71,16 @@ class TestTrace < Test::Unit::TestCase
         end
       end
       Tracer.stdout = open(IO::NULL, "w")
-      Tracer.on
+      begin
-      HogeError.new.to_s
+        Timeout.timeout(5) do
+          Tracer.on
+          HogeError.new.to_s
+        end
+      rescue Timeout::Error
+        # ok. there are no SEGV or critical error
+      rescue SystemStackError => e
+        # ok.
+      end
     end;
   end
 end