Ensure Debian test are passing

.github/workflows/docs.yml

@@ -9,7 +9,7 @@ jobs:
     strategy:
       max-parallel: 4
       matrix:
-        python-version: [3.7]
+        python-version: [3.8]
 
     steps:
       - name: Checkout code

vulnerabilities/importers/debian.py

@@ -131,7 +131,12 @@ def _parse(self, pkg_name: str, records: Mapping[str, Any]) -> List[Advisory]:
         return advisories
 
     def response_is_new(self):
-        date_str = requests.head(self.config.debian_tracker_url).headers.get("last-modified")
+        """
+        Return True if a request response is for new data likely changed or
+        updated since we last checked.
+        """
+        head = requests.head(self.config.debian_tracker_url)
+        date_str = head.headers.get("last-modified")
         last_modified_date = dateparser.parse(date_str)
         if self.config.last_run_date:
             return self.config.last_run_date < last_modified_date

vulnerabilities/tests/test_debian.py

@@ -20,8 +20,10 @@
 #  for any legal advice.
 #  VulnerableCode is a free software code scanning tool from nexB Inc. and others.
 #  Visit https://github.com/nexB/vulnerablecode/ for support and download.
+
 import json
 import os
+from dateutil import parser as dateparser
 from unittest.mock import patch
 from unittest.mock import MagicMock
 
@@ -45,14 +47,16 @@ def setUpClass(cls) -> None:
         cls.importer = models.Importer.objects.create(
             name="debian_unittests",
             license="",
-            last_run="2019-08-05 13:14:17.733232+05:30",
+            last_run=dateparser.parse("2019-08-05 13:14:17.733232+05:30"),
             data_source="DebianDataSource",
             data_source_cfg={"debian_tracker_url": "https://security.example.com/json"},
         )
+        return super().setUpClass()
 
-    @classmethod
-    def tearDownClass(cls) -> None:
-        pass
+    def tearDown(self) -> None:
+        self.importer.data_source_cfg = {"debian_tracker_url": "https://security.example.com/json"}
+        self.importer.last_run = dateparser.parse("2019-08-05 13:14:17.733232+05:30")
+        self.importer.save()
 
     def test_import(self):
         runner = ImportRunner(self.importer, 5)
@@ -84,12 +88,12 @@ def test_response_is_new(self):
         mock_resp.headers = {"last-modified": "Wed, 05 Aug 2021 09:12:19 GMT"}
 
         with patch("vulnerabilities.importers.debian.requests.head", return_value=mock_resp):
-            assert test_data_source.response_is_new() is True
+            assert test_data_source.response_is_new()
 
-        mock_resp.headers = {"last-modified": "Wed, 05 Aug 2019 09:12:19 GMT"}
+        mock_resp.headers = {"last-modified": "Wed, 04 Aug 2019 09:12:19 GMT"}
 
         with patch("vulnerabilities.importers.debian.requests.head", return_value=mock_resp):
-            assert test_data_source.response_is_new() is False
+            assert not test_data_source.response_is_new()
 
     def assert_for_package(self, name, version, release, cve_ids=None):
         qs = models.Package.objects.filter(