add option for an upload limit

[goapunk]

• add option for an upload limit
• return the first form error as JsonResponse so the real error is shown to the user (instead of a generic upload failed)
• add test_settings for pytest to make testing the file size easier
• add tests for file extension and file size on upload

[hvlads]

Hi @goapunk. Thank you for your work. What is the purpose of test_settings, which repeats exactly settings.py ? maybe it's better to use override_settings?

@override_settings(CKEDITOR_5_MAX_FILE_SIZE=0.06)
def test_upload_file_too_big(admin_client, file_big):
    ...

[goapunk]

Hi @hvlads , I changed it to import all settings from settings.py to make it more readable now. Using @override_settings sadly doesn't work as the value is not read dynamically but set when initializing the FileMaxSizeValidator. I don't know how else to do it (except for changing the logic in the validator itself)