Export ReadThrough in the csv export

[ccamara]

This PR is an attempt (my first code contribution to bookwyrm and my first experience with Django -be warned!) to fix #2965 and include any book progress when exporting to CSV file.

[ccamara]

Suggestions, comments and improvements are very welcome!

[hughrun]

This works really nicely!

A couple of suggestions, hopefully they make sense but let me know if not.

[hughrun]

You can fix the pylint error by adding to the disable comment at the top of the function:

# pylint: disable=no-self-use,too-many-locals
@method_decorator(login_required, name="dispatch")
class Export(View):

The test is failing because you're changing the output of the export file (which is the point!)

You should be able to adjust this test by adding the new headers, and three more commas to the next row (since there are no readthroughs in that test).

You can test whether this works locally by running:

./bw-dev pytest bookwyrm/tests/views/preferences/test_export.py

Let me know if you need help or advice with this. If you're feeling adventurous you could add a test to check the dates output properly, but it's not required.

[ccamara]

Thanks again for the guidance @hughrun ! I've made multiple commits to address the issues you flagged!

[hughrun]

You're nearly there!

You can fix the linting errors by running ./bw-dev black to reformat, and adjusting the too-many-locals comment as per my note.

To check pylint won't complain you can run ./bw-dev pylint. It does take a little while so don't panic if it looks like your console is hanging.

[ccamara]

Thanks again for this, @hughrun !

I believe my last commits should fix everything.