Worked on the Shopify/rails repository to deliver parallel testing replica database support, focusing on improving the reliability of integration tests. Implemented a solution in Ruby on Rails that enabled the use of replica databases within the parallel testing setup, ensuring each parallel worker accessed the correct database instance. This approach addressed issues where tests previously selected the base test database, which led to inconsistent results and flaky CI runs. By refining database management and routing logic, the work enhanced the determinism of the test suite. Emphasized robust testing practices and database management skills to increase confidence in continuous integration deployments.