Synchronize the test thread sleep

1 files changed, 8 insertions, 1 deletions

diff --git a/test/ruby/test_thread.rb b/test/ruby/test_thread.rb
index a018f3cdac..afcf1fb463 100644
--- a/test/ruby/test_thread.rb
+++ b/test/ruby/test_thread.rb
@@ -30,16 +30,23 @@ class TestThread < Test::Unit::TestCase
 
   def test_inspect
     m = Thread::Mutex.new
+    cv1 = Thread::ConditionVariable.new
+    cv2 = Thread::ConditionVariable.new
     m.lock
     line = __LINE__+1
     th = Module.new {break module_eval("class C\u{30b9 30ec 30c3 30c9} < Thread; self; end")}.start do
-      m.synchronize {}
+      m.synchronize do
+        cv2.signal
+        cv1.wait(m)
+      end
     end
+    cv2.wait(m)
     s = th.inspect
     assert_include(s, "::C\u{30b9 30ec 30c3 30c9}:")
     assert_include(s, " #{__FILE__}:#{line} ")
     assert_equal(s, th.to_s)
   ensure
+    cv1.signal
     m.unlock
     th.join
   end