How do you perform unit testing of DataWeave transformations in MUnit?

• A. Use only JUnit-based tests and skip DataWeave assertions.
• B. Test manually by running the flow with a sample payload and inspecting results.
• C. Create MUnit tests that exercise input payloads and assert expected transformed outputs using DataWeave assertions.
• D. DataWeave transformations cannot be tested in MUnit.

Answer: (C)

Testing DataWeave transformations in MUnit is done by creating MUnit test flows that feed the transformation with concrete input payloads and then verify the transformed output against expected results using DataWeave-based assertions. This approach makes the transformation logic verifiable in isolation, ensuring that given a specific input, the DataWeave script produces the exact structure and values you expect. You typically set up a test that supplies a sample payload (and any needed properties), invoke the Transform Message or the flow under test, and then use assertions to compare the actual payload to the expected one, often expressing the check with a DataWeave expression to validate nested fields, types, or arrays.

This is preferable because it provides automated, repeatable verification of the transformation itself, catch regressions, and leverages MUnit’s testing capabilities rather than relying on manual testing or external test frameworks. The other approaches—using only JUnit without DataWeave checks, or testing manually by running flows and inspecting results, or believing DataWeave cannot be tested in MUnit—do not offer the same automated, targeted validation of the transformation logic.