What is the reason this project uses inheritance rather than implementing Junit's Rule?

[BenjaminMalley]

Hi, thanks for this project! I'm curious about the rationale for using inheritance rather than implementing a Junit Rule. If I understand correctly how this works, it seems like the reuse a SparkContext in multiple tests outlined here could be resolved by implementing rule and letting the test implementation decide on granularity using the @ClassRule or @Rule annotations. I'm curious if the Rule approach was tried already and deemed inadequate. Thanks!