Development: improve test portability (#12187)

* Fix: improve test portability

* Make settings always consistent

* Make a few more tests deterministic wrt settings

* Dont pollute settings for this one

* Fix timezone issue with mail parser

* Update test_parser.py

* Uh, I guess OCR gives variants for this

---------

Co-authored-by: shamoon <4887959+shamoon@users.noreply.github.com>

src/paperless_mail/parsers.py

@@ -5,6 +5,7 @@ from pathlib import Path
 from bleach import clean
 from bleach import linkify
 from django.conf import settings
+from django.utils import timezone
 from django.utils.timezone import is_naive
 from django.utils.timezone import make_aware
 from gotenberg_client import GotenbergClient
@@ -332,7 +333,9 @@ class MailDocumentParser(DocumentParser):
         if data["attachments"]:
             data["attachments_label"] = "Attachments"
 
-        data["date"] = clean_html(mail.date.astimezone().strftime("%Y-%m-%d %H:%M"))
+        data["date"] = clean_html(
+            timezone.localtime(mail.date).strftime("%Y-%m-%d %H:%M"),
+        )
         data["content"] = clean_html(mail.text.strip())
 
         from django.template.loader import render_to_string

src/paperless_mail/tests/test_parsers.py

@@ -6,6 +6,7 @@ from unittest import mock
 import httpx
 import pytest
 from django.test.html import parse_html
+from django.utils import timezone
 from pytest_django.fixtures import SettingsWrapper
 from pytest_httpx import HTTPXMock
 from pytest_mock import MockerFixture
@@ -634,13 +635,14 @@ class TestParser:
         THEN:
             - Resulting HTML is as expected
         """
-        mail = mail_parser.parse_file_to_message(html_email_file)
-        html_file = mail_parser.mail_to_html(mail)
+        with timezone.override("UTC"):
+            mail = mail_parser.parse_file_to_message(html_email_file)
+            html_file = mail_parser.mail_to_html(mail)
 
-        expected_html = parse_html(html_email_html_file.read_text())
-        actual_html = parse_html(html_file.read_text())
+            expected_html = parse_html(html_email_html_file.read_text())
+            actual_html = parse_html(html_file.read_text())
 
-        assert expected_html == actual_html
+            assert expected_html == actual_html
 
     def test_generate_pdf_from_mail(
         self,