1 files changed, 5 insertions, 0 deletions
diff --git a/test/ruby/test_sprintf.rb b/test/ruby/test_sprintf.rb
index a07ac7908b..163d37256c 100644
--- a/test/ruby/test_sprintf.rb
+++ b/test/ruby/test_sprintf.rb
@@ -524,12 +524,17 @@ class TestSprintf < Test::Unit::TestCase
   end
 
   def test_no_hidden_garbage
+    skip unless Thread.list.size == 1
+
     fmt = [4, 2, 2].map { |x| "%0#{x}d" }.join('-') # defeats optimization
     ObjectSpace.count_objects(res = {}) # creates strings on first call
+    GC.disable
     before = ObjectSpace.count_objects(res)[:T_STRING]
     val = sprintf(fmt, 1970, 1, 1)
     after = ObjectSpace.count_objects(res)[:T_STRING]
     assert_equal before + 1, after, 'only new string is the created one'
     assert_equal '1970-01-01', val
+  ensure
+    GC.enable
   end
 end