org.apache.spark.streaming.TrackStateByKeySuite

(It is not a test)
state - get, exists, update, remove,
trackStateByKey - basic operations with advanced API
trackStateByKey - basic operations with simple API
trackStateByKey - checkpoint durations
trackStateByKey - driver failure recovery
trackStateByKey - initial states, with nothing emitted
trackStateByKey - state removing
trackStateByKey - state timing out
trackStateByKey - states as emitted records
trackStateByKey - type inferencing and class tags