When writing unit tests in Python you may find yourself switching back and forth between your code editor window and terminal to re-run your tests.

You can avoid this by using inotify. In short, it can re-run your tests when you change any Python files in your project. Here are some little scripts to help you do that.

First, install:

sudo apt install -y inotify-tools

If you're using bash, add this to your ~/.bashrc and restart your terminal:

function ptw() {
   pytest $1
   while find -name "*.py" | inotifywait -e close_write --fromfile - ;
       do pytest $1
   done
}

If you're using Fish, add to ~/.config/fish/config.fish and restart your terminal:

function ptw
   pytest $argv
   while find -name "*.py" | inotifywait -e close_write --fromfile - ;
       pytest $argv
   end
end

Now instead of running your tests the regular way:

pytest test_stuff.py

Run them like so:

ptw test_stuff.py

When the tests finish you'll see the process does not exit, and when you edit a .py file in your project the tests will automatically re-run.

Over the course of your day this will yield significant time savings!

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