During March 2025, Lukasz Biegaj developed SpEL template-based default expressions for scenario testing in the TouK/nussknacker repository. He implemented a system that defaults dry-run parameters and Avro or JSON string expressions to SpEL templates, ensuring deterministic and reliable scenario validation. Using Java and Scala, Lukasz aligned the test suite to leverage spelTemplate usage, focusing on correct parsing and evaluation of templates. His work included targeted test fixes to stabilize the suite and reduce flaky scenarios. This backend development effort improved test coverage and reduced manual parameter tuning, demonstrating depth in test-driven development and integration with Avro/JSON pipelines.