1 files changed, 10 insertions, 0 deletions
diff --git a/test/ruby/test_string.rb b/test/ruby/test_string.rb
index 29ad98beaf..57e7dae18f 100644
--- a/test/ruby/test_string.rb
+++ b/test/ruby/test_string.rb
@@ -105,6 +105,16 @@ PREP
 CODE
   end
 
+  # Bug #18154
+  def test_initialize_nofree_memory_leak
+    assert_no_memory_leak([], <<-PREP, <<-CODE, rss: true)
+code = proc {0.to_s.__send__(:initialize, capacity: 10000)}
+1_000.times(&code)
+PREP
+100_000.times(&code)
+CODE
+  end
+
   def test_AREF # '[]'
     assert_equal("A",  S("AooBar")[0])
     assert_equal("B",  S("FooBaB")[-1])