diff --git a/test/-ext-/string/test_nofree.rb b/test/-ext-/string/test_nofree.rb
index 12bf33afcc..fe2bf6b792 100644
--- a/test/-ext-/string/test_nofree.rb
+++ b/test/-ext-/string/test_nofree.rb
@@ -3,9 +3,10 @@ require 'test/unit'
 class Test_StringNoFree < Test::Unit::TestCase
   def test_no_memory_leak
     bug10942 = '[ruby-core:68436] [Bug #10942] no leak on nofree string'
-    code = '100_000.times {Bug::String.nofree << "a" * 100}'
+    code = '.times {Bug::String.nofree << "a" * 100}'
     assert_no_memory_leak(%w(-r-test-/string/string),
-                          code, code,
-                          bug10942, rss: true, limit: 1.1)
+                          "100_000#{code}",
+                          "1_000_000#{code}",
+                          bug10942, rss: true)
   end
 end