almost there on the task tests

tests/conftest.py

@@ -89,6 +89,7 @@ def metrics_timing(*args, **kwargs):
 def metrics():
     return pretend.stub(
         event=pretend.call_recorder(lambda *args, **kwargs: None),
+        gauge=pretend.call_recorder(lambda *args, **kwargs: None),
         increment=pretend.call_recorder(lambda *args, **kwargs: None),
         histogram=pretend.call_recorder(lambda *args, **kwargs: None),
         timing=pretend.call_recorder(lambda *args, **kwargs: None),

tests/unit/packaging/test_tasks.py

@@ -23,9 +23,11 @@
 from warehouse.accounts.models import WebAuthn
 from warehouse.packaging.models import Description
 from warehouse.packaging.tasks import (
+    check_file_archive_tasks_outstanding,
     compute_2fa_mandate,
     compute_2fa_metrics,
     sync_bigquery_release_files,
+    sync_file_to_archive,
     update_bigquery_release_files,
     update_description_html,
 )
@@ -43,6 +45,43 @@
 )
 
 
+def test_sync_file_to_archive(db_request):
+    file = FileFactory(archived=False)
+    primary_stub = pretend.stub(
+        get_metadata=pretend.call_recorder(lambda path: {"fizz": "buzz"}),
+        get=pretend.call_recorder(
+            lambda path: pretend.stub(read=lambda: b"my content")
+        ),
+    )
+    archive_stub = pretend.stub(
+        store=pretend.call_recorder(lambda filename, path, meta=None: None)
+    )
+    db_request.find_service = pretend.call_recorder(
+        lambda iface, name=None: {"primary": primary_stub, "archive": archive_stub}[
+            name
+        ]
+    )
+
+    sync_file_to_archive(db_request, file.id)
+
+    assert file.archived
+
+    assert primary_stub.get_metadata.calls == [pretend.call(file.path)]
+    assert primary_stub.get.calls == [pretend.call(file.path)]
+    assert archive_stub.store.calls == [pretend.call()]
+
+
+def test_check_file_archive_tasks_outstanding(db_request, metrics):
+    archived_files = [FileFactory(archived=True) for _ in range(12)]
+    unarchived_files = [FileFactory(archived=False) for _ in range(3)]
+
+    check_file_archive_tasks_outstanding(db_request)
+
+    assert metrics.gauge.calls == [
+        pretend.call("warehouse.packaging.files.not_archived", 3)
+    ]
+
+
 def test_update_description_html(monkeypatch, db_request):
     current_version = "24.0"
     previous_version = "23.0"