Developed a comprehensive smoke test suite for the NHSDigital/dtos-cohort-manager repository, focusing on automated validation of critical data flows such as file upload and cohort distribution. Leveraged C#, SpecFlow, and Azure Blob Storage to implement robust test environment scaffolding, including helpers for database and storage interactions. The suite covered scenarios like successful uploads, data validation against SQL databases, amended-record processing, and targeted exception handling. This work enhanced early defect detection and reduced production risk by ensuring key workflows were thoroughly tested before release, contributing to improved quality assurance and greater confidence in the reliability of data-intensive cohort management features.