fix: disk image

tests/test_backend.py

@@ -197,6 +197,60 @@ class BackendTests(unittest.TestCase):
                 (content_dir.parent.parent / ".progression-write-test").exists()
             )
 
+    @patch("progression_backend.workshop.subprocess.run")
+    def test_steamcmd_runner_forces_mounted_install_root(self, run: Mock) -> None:
+        with tempfile.TemporaryDirectory() as directory:
+            root = Path(directory)
+            executable = root / "steamcmd"
+            executable.write_text("", encoding="utf-8")
+            content_dir = (
+                root / "steamapps" / "workshop" / "content" / "294100"
+            )
+            run.return_value = Mock(returncode=0, stdout="", stderr="")
+            runner = SteamCmdRunner(str(executable), content_dir, 60)
+
+            runner.run_batch(["123456"])
+
+            command = run.call_args.args[0]
+            self.assertEqual(
+                command[:5],
+                [
+                    str(executable.resolve()),
+                    "+force_install_dir",
+                    str(root),
+                    "+login",
+                    "anonymous",
+                ],
+            )
+
+    def test_steamcmd_io_recovery_preserves_completed_mods(self) -> None:
+        with tempfile.TemporaryDirectory() as directory:
+            content_dir = (
+                Path(directory)
+                / "steamapps"
+                / "workshop"
+                / "content"
+                / "294100"
+            )
+            completed_mod = content_dir / "123456" / "About"
+            completed_mod.mkdir(parents=True)
+            (completed_mod / "About.xml").write_text("<ModMetaData />")
+            workshop_dir = content_dir.parent.parent
+            manifest = workshop_dir / "appworkshop_294100.acf"
+            manifest.write_text("stale", encoding="utf-8")
+            staging = workshop_dir / "downloads" / "294100"
+            staging.mkdir(parents=True)
+            (staging / "partial.bin").write_bytes(b"partial")
+            runner = SteamCmdRunner("steamcmd", content_dir, 60)
+
+            moved = runner.recover_io_failure()
+
+            self.assertEqual(len(moved), 2)
+            self.assertFalse(manifest.exists())
+            self.assertFalse(staging.exists())
+            self.assertTrue((completed_mod / "About.xml").is_file())
+            self.assertEqual(runner.recover_io_failure(), [])
+
     def test_rml_uses_workshop_id_and_escapes_names(self) -> None:
         payload = generate_rml(
             [