A new gem, simplecov-compare, has been introduced to help compare test coverage results between two SimpleCov runs.
Instead of relying on external services or pipelines, it works directly with JSON output files, highlighting differences in line coverage across files and result sets. The tool includes formatters and reporters to display those differences, with support for both the CLI and Ruby API.
This is the link to read the full article: https://kevinjmurphy.com/posts/announcing-simplecov-compare/