1 files changed, 12 insertions, 0 deletions
diff --git a/activesupport/test/core_ext/hash/transform_keys_test.rb b/activesupport/test/core_ext/hash/transform_keys_test.rb
index a7e12117f3..5a0b99e22c 100644
--- a/activesupport/test/core_ext/hash/transform_keys_test.rb
+++ b/activesupport/test/core_ext/hash/transform_keys_test.rb
@@ -24,9 +24,21 @@ class TransformKeysTest < ActiveSupport::TestCase
     assert_equal Enumerator, enumerator.class
   end
 
+  test "transform_keys! returns an Enumerator if no block is given" do
+    original = { a: 'a', b: 'b' }
+    enumerator = original.transform_keys!
+    assert_equal Enumerator, enumerator.class
+  end
+
   test "transform_keys is chainable with Enumerable methods" do
     original = { a: 'a', b: 'b' }
     mapped = original.transform_keys.with_index { |k, i| [k, i].join.to_sym }
     assert_equal({ a0: 'a', b1: 'b' }, mapped)
   end
+
+  test "transform_keys! is chainable with Enumerable methods" do
+    original = { a: 'a', b: 'b' }
+    original.transform_keys!.with_index { |k, i| [k, i].join.to_sym }
+    assert_equal({ a0: 'a', b1: 'b' }, original)
+  end
 end