* Test added for all kernels
* Same examples as provided in the documentation (`specifics.md`)
* Used the same use case for all examples: sum of the first 100 whole numbers

Note: I've not automatically tested `local_sparklyr.ipynb` since it creates by default the `metastore_db` dir and the `derby.log` file in the working directory. Since I mount it in `RO` it's not working. I'm struggling to set it elsewhere...