Alex Loyko expanded test coverage for the opensearch-project/opensearch-api-specification repository by developing end-to-end tests for the Msearch API, focusing on multi-search functionality across books and movies indices. Alex implemented comprehensive test data setup and result verification using YAML, ensuring deterministic outcomes and reliable validation of multi-index search workflows. The work integrated seamlessly with the existing test harness, streamlining continuous integration feedback and reducing the risk of regressions. By emphasizing API testing and automation best practices, Alex established a robust foundation for future multi-index scenarios, enhancing confidence in search correctness and supporting maintainable, scalable test coverage for the Search API.