1 files changed, 10 insertions, 0 deletions
diff --git a/activesupport/test/core_ext/hash_ext_test.rb b/activesupport/test/core_ext/hash_ext_test.rb
index 26e65075eb..5d2053f106 100644
--- a/activesupport/test/core_ext/hash_ext_test.rb
+++ b/activesupport/test/core_ext/hash_ext_test.rb
@@ -245,6 +245,16 @@ class HashExtTest < Test::Unit::TestCase
     assert(!indiff.keys.any? {|k| k.kind_of? String}, "A key was converted to a string!")
   end
 
+  def test_deep_merge
+    hash_1 = { :a => "a", :b => "b", :c => { :c1 => "c1", :c2 => "c2", :c3 => { :d1 => "d1" } } }
+    hash_2 = { :a => 1, :c => { :c1 => 2, :c3 => { :d2 => "d2" } } }
+    expected = { :a => 1, :b => "b", :c => { :c1 => 2, :c2 => "c2", :c3 => { :d1 => "d1", :d2 => "d2" } } }
+    assert_equal expected, hash_1.deep_merge(hash_2)
+
+    hash_1.deep_merge!(hash_2)
+    assert_equal expected, hash_1
+  end
+
   def test_reverse_merge
     defaults = { :a => "x", :b => "y", :c => 10 }.freeze
     options  = { :a => 1, :b => 2 }