Integration and Unit testing Nifi process groups

I have a few Nifi process groups which I want to run integration tests on before promoting to production. The issue is that I can't seem to find any documentation on how to do so.

Data Provenance seems like a promising tool to accomplish what I want, however, over the course of the flowfile's lifecycle, data is published to/from kafka or the file system. As a result, the flowfile UUID changes so I cannot query for it using the nifi-api.

Additionally, I know that Nifi offers a TestRunner library to run tests, however, this seems to only be for processors/processor groups generated via code and not the UI.

Does anyone know of a tool, framework, or pattern for integration and unit testing nifi process groups. Ideally this would be a solution where you can see input vs output programatically compare input/output of the processor/processor group without modifying the existing workflow to accommodate tests.