Test driven development for Jupyter?

Some ideas of realising Test Driven Development (TDD) with the Jupyter notebook, following discussion on the testing-in-python mailing list: http://lists.idyll.org/pipermail/testing-in-python/2016-June/006770.html

Directory convert-to-py

Example that converts a libary notebook foo.ipynb into a python file foo.py which is tested by tests in test_foo (which in turn is produced from test_foo.ipynb.

The basic ideas is to write the tests as conventional test code (for example one per cell, if we write the tests in test_foo.ipynb, but we could also just write the tests in a normal python file test_foo.py), and to convert the notebook with the implementation of the tested functionality to another python file, and run testing on the resulting python files.