FWIW, I was speaking specifically to being able to run Spark, and manage its lifecycle, all inside the same process as the unit test code. Which is something that I'll openly concede isn't much more than a fun party trick for most people's purposes, but it does happen to serve me well.

In a past life, I was involved in data engineering at a .NET shop, and being able to migrate parts of our process to something like Spark without having to rewrite or otherwise severely damage it would have made me very happy. Even better if I could stay inside Visual Studio, and bang on it from an F# interactive session.

Wild speculation, but if you can produce type providers that know how to tame `DataSet[Row]`, you might have some nonzero number of F# hipsters like me kissing your feet.

(Or not. Like I said, my perspective on Spark is unusual.)