The AWS Developers Podcast Local Unit Testing for Step Functions
Nov 28, 2025
Jas Narula, a Product Manager on the AWS Step Functions team, shares exciting updates on local unit testing for AWS workflows. He introduces the enhanced Test State API, allowing developers to test workflows with greater accuracy. Key features include support for advanced states like Map and Parallel, along with improved mocking capabilities. Jas discusses collaboration with LocalStack for offline testing and how popular frameworks like PyTest and Jest can be integrated. This new approach transforms Step Functions development into a more traditional test-driven environment.
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API-Based Local Testing On Real Runtime
- AWS replaced the discontinued Step Functions Local container with an enhanced Test State API that runs on the production runtime.
- This API-based approach gives higher-fidelity local unit testing by executing on the real Step Functions runtime remotely.
Choose Remote Or LocalStack For Tests
- Use the remote Test State API when you have network access to run high-fidelity unit tests on the production runtime.
- If you need offline or network-isolated testing, switch the endpoint to LocalStack which mirrors the same API enhancements.
Integrate Tests Into Your Existing Framework
- Integrate the Test State API into your existing unit test framework (PyTest, Jest, etc.) to automate assertions on state transitions.
- Use the provided Python helper library on GitHub to reduce boilerplate and accelerate test development.