diff --git a/swh/loader/package/debian/tests/test_debian.py b/swh/loader/package/debian/tests/test_debian.py
--- a/swh/loader/package/debian/tests/test_debian.py
+++ b/swh/loader/package/debian/tests/test_debian.py
@@ -402,11 +402,11 @@
 
     """
     for package_artifacts in [{}, PACKAGE_FILES]:
-        actual_revision = resolve_revision_from(package_artifacts, {})
+        actual_revision = resolve_revision_from({}, package_artifacts)
         assert actual_revision is None
 
     for known_artifacts in [{}, PACKAGE_FILES]:
-        actual_revision = resolve_revision_from({}, known_artifacts)
+        actual_revision = resolve_revision_from(known_artifacts, {})
         assert actual_revision is None
 
     known_package_artifacts = {