February 2026 monthly summary for folio-org/mod-data-export: Focused on strengthening reliability and business value through targeted unit-test coverage of core export services. Key features delivered include comprehensive unit tests for MappingProfileService (user info and locking), file upload service (validation and error handling), ExportDeletedMarcIdsService (null requests and dependency interactions), and S3ExportsUploader (IOException handling during uploads). The tests also cover failure modes when the S3 client fails, improving resilience for production deployments. Major bugs fixed: None reported this month; effort centered on preventing regressions by expanding test coverage and validating critical paths. Overall impact and accomplishments: Increased release confidence, reduced regression risk in the data export pipeline, and improved maintainability. This work enables faster CI feedback and safer refactors across core services. Technologies/skills demonstrated: Java-based unit testing with JUnit, mocking and test doubles, validation and error handling, AWS S3 interaction testing, and strong test-driven development practices contributing to robust CI outcomes.