ensure `#compact` of HWIDA to return HWIDA

`Hash#compact` of Ruby native returns new hash.
Therefore, in order to return HWIDA as in the past version, need to
define own `#compact` to HWIDA.

Related: #26868

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 bea0a84b53..05813ad388 100644
--- a/activesupport/test/core_ext/hash_ext_test.rb
+++ b/activesupport/test/core_ext/hash_ext_test.rb
@@ -589,6 +589,16 @@ class HashExtTest < ActiveSupport::TestCase
     assert_instance_of ActiveSupport::HashWithIndifferentAccess, indifferent_strings
   end
 
+  def test_indifferent_compact
+    hash_contain_nil_value = @strings.merge("z" => nil)
+    hash = ActiveSupport::HashWithIndifferentAccess.new(hash_contain_nil_value)
+    compacted_hash = hash.compact
+
+    assert_equal(@strings, compacted_hash)
+    assert_equal(hash_contain_nil_value, hash)
+    assert_instance_of ActiveSupport::HashWithIndifferentAccess, compacted_hash
+  end
+
   def test_indifferent_to_hash
     # Should convert to a Hash with String keys.
     assert_equal @strings, @mixed.with_indifferent_access.to_hash