1 files changed, 8 insertions, 0 deletions
diff --git a/test/date/test_date_new.rb b/test/date/test_date_new.rb
index fe9a631ad0..6ea9c69041 100644
--- a/test/date/test_date_new.rb
+++ b/test/date/test_date_new.rb
@@ -267,4 +267,12 @@ class TestDateNew < Test::Unit::TestCase
     assert_in_delta(t, t2, t - z + 2)
   end
 
+  def test_memsize
+    require 'objspace'
+    t = DateTime.now
+    size = ObjectSpace.memsize_of(t)
+    t.__send__(:initialize_copy, Date.today)
+    assert_instance_of(DateTime, t)
+    assert_equal(size, ObjectSpace.memsize_of(t), "not reallocated but memsize changed")
+  end
 end