diff --git a/test/ruby/test_gc.rb b/test/ruby/test_gc.rb
index 7b0c0b85ab..06bf038cae 100644
--- a/test/ruby/test_gc.rb
+++ b/test/ruby/test_gc.rb
@@ -406,6 +406,9 @@ class TestGc < Test::Unit::TestCase
     # This test prevents bugs like [Bug #18929]
 
     assert_separately %w[--disable-gem], __FILE__, __LINE__, <<-'RUBY'
+      # Grow the heap
+      @ary = 100_000.times.map { Object.new }
+
       # Warmup to make sure heap stabilizes
       1_000_000.times { Object.new }