Add E2E tests for: - [x] https://github.com/torrust/torrust-index-backend/issues/107 - [x] https://github.com/torrust/torrust-index-backend/issues/111 - [x] https://github.com/torrust/torrust-index-backend/issues/109 - [x] https://github.com/torrust/torrust-index-backend/issues/118 - [x] https://github.com/torrust/torrust-index-backend/issues/120 See: https://github.com/torrust/torrust-index-backend/pull/105
