Oleksandr Havryliak enhanced the percona/percona-backup-mongodb repository by building robust CI/CD workflows focused on test coverage and environment modernization. He introduced an end-to-end coverage reporting system using Go, YAML, and GitHub Actions, integrating Codecov for unified visibility into functional and unit test results. His work included automating coverage report generation, artifact management, and categorization of test types, which improved feedback loops and code quality metrics. Additionally, Oleksandr upgraded the CI environment to a newer Go toolchain, reducing test flakiness and aligning dependencies for future maintenance. His contributions demonstrated depth in DevOps automation and continuous integration best practices.