Best testing framework for Microsoft Azure solution

I'm looking for the most suitable Testing-framework for my Microsoft azure solution. To describe the overall process in simple word: there is an ingestion module with kafka, streamsets,..., to get the Data, a processing module and an interactive query module using spark.

It should be implemented some Unit tests, Module tests and QA-tests. I'm actually from java environment and therefore i thought about Spring boot with Cucumber/Gherkin for better human readability. But I'm not sure how complex it is to integrate spring boot into azure. And or that is a good Idea.

My other idea is .Net with specFlow. But is specFlow chargeable or for free?

What do you think guys, which way do you think is the better way to do that? I'm open for other suggestions.