How do I configure PyCharm to automatically and continuously run my unit tests?

I am late with answer, but here is official PyCharm documentation. The delay between your change and re-run can be decreased

https://www.jetbrains.com/pycharm/guide/tips/auto-run-tests/

This is very simple. Once you have created a run configuration for the unit tests, run them once manually. With the Run dialog open you will notice on the left hand size there are a group of icons arranged vertically. In that group is an icon with a circular arrow. Click that for the auto-run you seek. It behaves smartly. It doesn't just run continuously, but rather waits for you to make some changes in the code and for your to quiesce for a few seconds. At that point it appears you would be done with a change and the auto-repeat fires.

Please also see https://www.jetbrains.com/pycharm/help/rerunning-tests.html for some other great tips, such as only running failed tests.