There is no unit test for chown method in test_fileutils.rb with root account. Chown with root account has unique behaviour which can change the user ownership of the file.
This issue was solved with changeset r44387.
Vajrasky, thank you for reporting this issue.
Your contribution to Ruby is greatly appreciated.
May Ruby be with you.
test_fileutils.rb: tests for chown
test/fileutils/fileasserts.rb (assert_ownership_user): new
assertion for user ownership.
test/fileutils/test_fileutils.rb (test_chown_error),
(test_chown_without_permission, test_chown_with_root):
based on the patch by vajrasky (Vajrasky Kok) at [ruby-core:59298]. [Feature #9292]