fix: case when fetching vulnerabilities for 0 packages

vulnerabilities/fetch.py

@@ -50,28 +50,31 @@ def fetch_from_vulnerablecode(dataspace, batch_size, update, timeout, log_func=N
         timeout=timeout,
         log_func=log_func,
     )
+
     run_time = timer() - start_time
     if log_func:
         log_func(f"+ Created {intcomma(results.get('created', 0))} vulnerabilities")
         log_func(f"+ Updated {intcomma(results.get('updated', 0))} vulnerabilities")
         log_func(f"Completed in {humanize_time(run_time)}")
 
-    dataspace.vulnerabilities_updated_at = timezone.now()
-    dataspace.save(update_fields=["vulnerabilities_updated_at"])
-    log_func("Dataspace.vulnerabilities_updated_at updated")
+    if results:
+        dataspace.vulnerabilities_updated_at = timezone.now()
+        dataspace.save(update_fields=["vulnerabilities_updated_at"])
+        log_func("Dataspace.vulnerabilities_updated_at updated")
 
 
 def fetch_for_packages(
     queryset, dataspace, batch_size=50, update=True, timeout=None, log_func=None
 ):
     from product_portfolio.models import ProductPackage
 
+    results = {"created": 0, "updated": 0}
+
     object_count = queryset.count()
     if object_count < 1:
-        return
+        return results
 
     vulnerablecode = VulnerableCode(dataspace)
-    results = {"created": 0, "updated": 0}
 
     for index, batch in enumerate(chunked_queryset(queryset, batch_size), start=1):
         if log_func:

vulnerabilities/tests/test_fetch.py

@@ -58,6 +58,20 @@ def test_vulnerabilities_fetch_from_vulnerablecode(
         self.dataspace.refresh_from_db()
         self.assertIsNotNone(self.dataspace.vulnerabilities_updated_at)
 
+        buffer = io.StringIO()
+        dataspace_empty = Dataspace.objects.create(name="empty")
+        mock_fetch_for_packages.return_value = {}
+        fetch_from_vulnerablecode(
+            dataspace_empty, batch_size=1, update=True, timeout=None, log_func=buffer.write
+        )
+        expected = (
+            "0 Packages in the queue."
+            "+ Created 0 vulnerabilities"
+            "+ Updated 0 vulnerabilities"
+            "Completed in 0 seconds"
+        )
+        self.assertEqual(expected, buffer.getvalue())
+
     @mock.patch("dejacode_toolkit.vulnerablecode.VulnerableCode.bulk_search_by_purl")
     def test_vulnerabilities_fetch_for_packages(self, mock_bulk_search_by_purl):
         buffer = io.StringIO()