Travis: run `clean` before `test`
Travis: run `clean` before `test`
spark-notebook/spark-notebook,maasg/spark-notebook,andypetrella/spark-notebook,spark-notebook/spark-notebook,maasg/spark-notebook,maasg/spark-notebook,andypetrella/spark-notebook,spark-notebook/spark-notebook,spark-notebook/spark-notebook,maasg/spark-notebook,andypetrella/spark-notebook,andypetrella/spark-notebook