It is a recent PR that is working for Rails 4 but not for Rails 5.
Failure: AccessTokenTest#test_creation_is_audited [/home/marta/DevRepos/3scale/porta/test/models/access_token_test.rb:142] Minitest::Assertion: --- expected +++ actual @@ -1 +1 @@ -{"owner_id"=>12, "scopes"=>["stats"], "name"=>"Alaska_6", "permission"=>"rw", "created_at"=>2020-01-28 18:10:25 UTC, "updated_at"=>2020-01-28 18:10:25 UTC} +{"owner_id"=>12, "owner_type"=>"User", "scopes"=>["stats"], "name"=>"Alaska_6", "permission"=>"rw", "created_at"=>Tue, 28 Jan 2020 18:10:25 UTC +00:00, "updated_at"=>Tue, 28 Jan 2020 18:10:25 UTC +00:00} Failure: AccessTokenTest#test_deletion_is_audited [/home/marta/DevRepos/3scale/porta/test/models/access_token_test.rb:158] Minitest::Assertion: --- expected +++ actual @@ -1 +1 @@ -{"owner_id"=>13, "scopes"=>["stats"], "name"=>"Alaska_8", "permission"=>"rw", "created_at"=>2020-01-28 18:10:25 UTC, "updated_at"=>2020-01-28 18:10:25 UTC} +{"owner_id"=>13, "owner_type"=>"User", "scopes"=>["stats"], "name"=>"Alaska_8", "permission"=>"rw", "created_at"=>Tue, 28 Jan 2020 18:10:25 UTC +00:00, "updated_at"=>Tue, 28 Jan 2020 18:10:25 UTC +00:00} Failure: AccessTokenTest#test_timestamps_filled [/home/marta/DevRepos/3scale/porta/test/models/access_token_test.rb:126] Minitest::Assertion: --- expected +++ actual @@ -1 +1 @@ -2019-08-28 18:10:26 UTC +Wed, 28 Aug 2019 18:10:26 UTC +00:00 Failure: AccessTokenTest#test_update_is_audited [/home/marta/DevRepos/3scale/porta/test/models/access_token_test.rb:184] Minitest::Assertion: --- expected +++ actual @@ -1 +1 @@ -{"name"=>["initial-name", "updated-name"], "updated_at"=>[2020-01-28 18:10:26 UTC, 2020-01-28 18:10:26 UTC]} +{"name"=>["initial-name", "updated-name"]} 15 tests, 80 assertions, 4 failures, 0 errors, 0 skips