feat: snapshot/restore checkpoints (SAND-WP-0007)

Add workspace checkpoint API with SnapshotStore, extension hooks on
compose-ssh and saas-stub, manager orchestration, CLI/HTTP surface,
profile.compose-checkpoint, and docs/tests.

tests/test_snapshots.py

@@ -0,0 +1,172 @@
+"""Snapshot store and manager checkpoint tests."""
+
+from __future__ import annotations
+
+from datetime import UTC, datetime
+from pathlib import Path
+from unittest.mock import patch
+
+import pytest
+
+from sandboxer.core.manager import SandboxManager
+from sandboxer.lifecycle.store import SandboxStore
+from sandboxer.models import (
+    ActorType,
+    Consumer,
+    Reachability,
+    SandboxCreateRequest,
+    SandboxState,
+    SandboxStatus,
+    SnapshotRecord,
+)
+from sandboxer.snapshots.store import SnapshotStore
+
+
+class SnapshotBackend:
+    def supports_snapshots(self) -> bool:
+        return True
+
+    def provision(self, profile, inputs, host):
+        return {
+            "sandbox_id": "test1234",
+            "host": host,
+            "remote_dir": "/tmp/sandboxer/test1234",
+            "compose_project": "sbx-e2e-test1234",
+            "compose_file": "docker-compose.yml",
+            "ssh_user": "root",
+        }
+
+    def wait_ready(self, handle):
+        return {
+            "ssh": f"root@{handle['host']}",
+            "remote_dir": handle["remote_dir"],
+            "compose_project": handle["compose_project"],
+            "host": handle["host"],
+        }
+
+    def teardown(self, handle):
+        return {"compose_removed": "True", "remote_dir_removed": "True"}
+
+    def snapshot(self, handle):
+        return {
+            "snapshot_id": "snap12345678",
+            "artifact_path": "/tmp/sandboxer/snapshots/snap12345678.tar.gz",
+            "host": handle["host"],
+            "size_bytes": "4096",
+        }
+
+    def restore_from_snapshot(self, profile, snapshot_meta, inputs, host):
+        return {
+            "sandbox_id": "restored1",
+            "host": host,
+            "remote_dir": "/tmp/sandboxer/restored1",
+            "compose_project": "sbx-e2e-restored1",
+            "compose_file": "docker-compose.yml",
+            "ssh_user": "root",
+        }
+
+
+@pytest.fixture
+def store(tmp_path: Path) -> SandboxStore:
+    return SandboxStore(path=tmp_path / "sandboxes.json")
+
+
+@pytest.fixture
+def snapshots(tmp_path: Path) -> SnapshotStore:
+    return SnapshotStore(path=tmp_path / "snapshots.json")
+
+
+def _ready_status(sandbox_id: str = "test1234") -> SandboxStatus:
+    now = datetime.now(UTC)
+    return SandboxStatus(
+        sandbox_id=sandbox_id,
+        profile_id="profile.compose-checkpoint",
+        extension_id="ext.compose-ssh",
+        state=SandboxState.READY,
+        consumer=Consumer(actor=ActorType.ADM, project="sand-boxer"),
+        host="coulombcore",
+        reachability=Reachability(
+            ssh="root@coulombcore",
+            remote_dir="/tmp/sandboxer/test1234",
+            compose_project="sbx-e2e-test1234",
+            host="coulombcore",
+        ),
+        inputs={
+            "repo": "/tmp/repo",
+            "compose_file": "docker-compose.yml",
+            "ssh_user": "root",
+        },
+        created_at=now,
+        updated_at=now,
+        ready_at=now,
+    )
+
+
+def test_snapshot_store_roundtrip(snapshots: SnapshotStore) -> None:
+    now = datetime.now(UTC)
+    record = SnapshotRecord(
+        snapshot_id="snap12345678",
+        sandbox_id="test1234",
+        profile_id="profile.compose-checkpoint",
+        extension_id="ext.compose-ssh",
+        host="coulombcore",
+        artifact_path="/tmp/snap.tar.gz",
+        created_at=now,
+    )
+    snapshots.save(record)
+    loaded = snapshots.get("snap12345678")
+    assert loaded is not None
+    assert loaded.sandbox_id == "test1234"
+
+
+def test_manager_snapshot_and_restore(store: SandboxStore, snapshots: SnapshotStore) -> None:
+    store.save(_ready_status())
+    manager = SandboxManager(store=store, snapshots=snapshots)
+    backend = SnapshotBackend()
+
+    with (
+        patch("sandboxer.core.manager.resolve_backend", return_value=backend),
+        patch("sandboxer.core.manager.load_extension"),
+        patch("sandboxer.core.manager.emit_lifecycle_event", return_value=None),
+        patch("sandboxer.core.manager.load_profile"),
+        patch("sandboxer.core.manager.resolve_host", return_value="coulombcore"),
+    ):
+        record = manager.snapshot("test1234", name="pre-test")
+        assert record.snapshot_id == "snap12345678"
+        assert record.name == "pre-test"
+        assert record.size_bytes == 4096
+
+        status = manager.restore("snap12345678")
+        assert status.state == SandboxState.READY
+        assert status.sandbox_id == "restored1"
+        assert status.inputs.get("restored_from") == "snap12345678"
+
+
+def test_snapshot_requires_ready(store: SandboxStore, snapshots: SnapshotStore) -> None:
+    status = _ready_status()
+    status.state = SandboxState.PROVISIONING
+    store.save(status)
+    manager = SandboxManager(store=store, snapshots=snapshots)
+
+    with pytest.raises(RuntimeError, match="ready"):
+        manager.snapshot("test1234")
+
+
+def test_create_snapshot_restore_flow(store: SandboxStore, snapshots: SnapshotStore) -> None:
+    manager = SandboxManager(store=store, snapshots=snapshots)
+    backend = SnapshotBackend()
+    request = SandboxCreateRequest(
+        profile="profile.compose-checkpoint",
+        inputs={"repo": "/tmp/repo"},
+        consumer=Consumer(actor=ActorType.ADM, project="sand-boxer"),
+    )
+
+    with (
+        patch("sandboxer.core.manager.resolve_backend", return_value=backend),
+        patch("sandboxer.core.manager.emit_lifecycle_event", return_value=None),
+        patch("sandboxer.core.manager.resolve_host", return_value="coulombcore"),
+    ):
+        created = manager.create(request)
+        record = manager.snapshot(created.sandbox_id)
+        restored = manager.restore(record.snapshot_id)
+        assert restored.sandbox_id == "restored1"