https://github.com/timkpaine/jupyterlab_celltestsSimilar to the various other projects out there. One of the differentiating factors is this allows you to write tests for each cell without having to pollute the actual view (puts it in metadata). Another feature is the ability to enforce so called "linear execution" by adding assertions for max lines per cell, max functions per notebook, max classes per notebook, percent cell coverage, etc. Also provides a view for running lint and tests from jupyterlab.
Feedback welcome, we are about to introduce this into our production notebook platform.