diff --git a/ChangeLog b/ChangeLog
index 0bdfc65ba3..1b45e422f0 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Sun Apr 24 09:32:12 2016  Yuichiro Kaneko  <yui-knk@ruby-lang.org>
+
+	* test/ruby/test_array.rb: Add test cases for Array#sum with
+	  non-numeric objects.
+
 Sun Apr 24 04:21:27 2016  NARUSE, Yui  <naruse@ruby-lang.org>
 
 	* vm_insnhelper.c (INLINE): define as `inline` when it is optimized.
diff --git a/test/ruby/test_array.rb b/test/ruby/test_array.rb
index 4ae5f9f820..36f2b7d72d 100644
--- a/test/ruby/test_array.rb
+++ b/test/ruby/test_array.rb
@@ -2786,6 +2786,9 @@ class TestArray < Test::Unit::TestCase
     assert_float_equal(large_number+(small_number*10), [large_number, *[small_number]*10].sum)
     assert_float_equal(large_number+(small_number*10), [large_number/1r, *[small_number]*10].sum)
     assert_float_equal(large_number+(small_number*11), [small_number, large_number/1r, *[small_number]*10].sum)
+
+    assert_equal("abc", ["a", "b", "c"].sum(""))
+    assert_equal([1, [2], 3], [[1], [[2]], [3]].sum([]))
   end
 
   private