Achille Roussel developed custom storage support for the PromQL test suite in the grafana/prometheus repository, focusing on enhancing test flexibility and coverage. By modifying test functions to accept a storage parameter, Achille enabled the suite to run tests against different storage implementations, allowing for more targeted and storage-specific testing scenarios. This approach required updates to the test harness and careful integration with existing Go code, emphasizing robust software development and testing practices. The work addressed the need for adaptable test environments, deepening the suite’s utility for developers working with varied storage backends, and demonstrated thoughtful engineering within a focused scope.