Refuse prune apply when requested image inventories are unavailable

Assistant: codex
Assistant-Model: gpt-6-astra
Assistant-Session: 01a06ecb-456a-71c2-b41e-0755d336e883

tests/test_forgejo_package_prune.py

@@ -18,6 +18,36 @@ SPEC.loader.exec_module(prune)
 
 
 class ForgejoPackagePruneTests(unittest.TestCase):
+    def test_apply_refuses_any_unavailable_export_before_authentication(self):
+        with tempfile.TemporaryDirectory() as tmp:
+            root = Path(tmp)
+            good = root / "good.txt"
+            good.write_text("forgejo.coulomb.social/coulomb/app:live\n")
+            bad = root / "bad.txt"
+            for content in [None, b"", b"# no inventory\n", b"\xff"]:
+                with self.subTest(content=content):
+                    if content is not None:
+                        bad.write_bytes(content)
+                    with mock.patch.object(prune, "load_token") as auth, \
+                         mock.patch.object(prune, "build_delete_plans") as plans, \
+                         mock.patch.object(prune, "delete_version") as delete:
+                        result = prune.main([
+                            "--apply", "--live-images-file", str(good),
+                            "--live-images-file", str(bad),
+                        ])
+                    self.assertEqual(result, 2)
+                    auth.assert_not_called()
+                    plans.assert_not_called()
+                    delete.assert_not_called()
+
+    def test_non_forgejo_image_export_is_not_empty(self):
+        with tempfile.TemporaryDirectory() as tmp:
+            export = Path(tmp) / "images.txt"
+            export.write_text("nginx:stable\n")
+            protected, notes = prune.collect_live_images_from_files([export])
+            self.assertEqual(protected, set())
+            self.assertEqual(notes, [])
+
     def test_collect_protected_versions_from_helm_values(self) -> None:
         import tempfile