Default format selections on export action

[shimakaze-git]

Problem

#1373

This is the PR for this issue.

When there is only one formats like the code below,the format on the Export action does not display ---.
By default, you can select the contents specified in formats.

from import_export.admin import ExportActionModelAdmin
from import_export.formats import base_formats

class CategoryAdmin(ExportActionModelAdmin):

    formats = [base_formats.CSV]

Solution

In the ExportActionMixin constructor of import_export/admin.py, if the size of formats exceeds 1, add --- to choices.

Acceptance Criteria

• After modifying CategoryAdmin in tests/core/admin.py as follows, I confirmed that the format of the Export action in the admin screen is csv.

• I added a unit tests.

[coveralls]

Coverage increased (+0.001%) to 98.074% when pulling 9927b8c on shimakaze-git:main into 0d4340f on django-import-export:main.

[matthewhegarty]

Looks good. Thanks for adding this. I think we would add this into our forthcoming v3 release.

Please could you add unit tests to prove the contents of the choices list. For example, you could create a test class to verify the choices list passed into export_action_form_factory(). I don't know your level of experience but happy to help if required.

[shimakaze-git]

@matthewhegarty

ok! I added a unit tests.
Is this okay?

[matthewhegarty]

This looks great - thanks for adding the tests.

Would you be able to merge the release-3-x branch into this, and then squash commits? There should be a single commit with the log message:

Customize default format selections on export action (#1389)

Thanks so much for adding this.

[shimakaze-git]

@matthewhegarty

I've merged the release-3-x branch into the main branch.

[matthewhegarty]

Thanks @shimakaze-git - I've updated the changelog. I'm going to squash the commits and then merge.

[shimakaze-git]

@matthewhegarty Thanks!