feat(provisioner): add optional PVC support for sandbox volumes (#2020)

* feat(provisioner): add optional PVC support for sandbox volumes (#1978)

  Add SKILLS_PVC_NAME and USERDATA_PVC_NAME env vars to allow sandbox
  Pods to use PersistentVolumeClaims instead of hostPath volumes. This
  prevents data loss in production when pods are rescheduled across nodes.

  When USERDATA_PVC_NAME is set, a subPath of threads/{thread_id}/user-data
  is used so a single PVC can serve multiple threads. Falls back to hostPath
  when the new env vars are not set, preserving backward compatibility.

* add unit test for provisioner pvc volumes

* refactor: extract shared provisioner_module fixture to conftest.py

Agent-Logs-Url: https://github.com/bytedance/deer-flow/sessions/e7ccf708-c6ba-40e4-844a-b526bdb249dd

Co-authored-by: WillemJiang <219644+WillemJiang@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: JeffJiang <for-eleven@hotmail.com>

backend/tests/test_provisioner_kubeconfig.py

@@ -2,25 +2,9 @@
 
 from __future__ import annotations
 
-import importlib.util
-from pathlib import Path
 
-
-def _load_provisioner_module():
-    """Load docker/provisioner/app.py as an importable test module."""
-    repo_root = Path(__file__).resolve().parents[2]
-    module_path = repo_root / "docker" / "provisioner" / "app.py"
-    spec = importlib.util.spec_from_file_location("provisioner_app_test", module_path)
-    assert spec is not None
-    assert spec.loader is not None
-    module = importlib.util.module_from_spec(spec)
-    spec.loader.exec_module(module)
-    return module
-
-
-def test_wait_for_kubeconfig_rejects_directory(tmp_path):
+def test_wait_for_kubeconfig_rejects_directory(tmp_path, provisioner_module):
     """Directory mount at kubeconfig path should fail fast with clear error."""
-    provisioner_module = _load_provisioner_module()
     kubeconfig_dir = tmp_path / "config_dir"
     kubeconfig_dir.mkdir()
 
@@ -33,9 +17,8 @@ def test_wait_for_kubeconfig_rejects_directory(tmp_path):
         assert "directory" in str(exc)
 
 
-def test_wait_for_kubeconfig_accepts_file(tmp_path):
+def test_wait_for_kubeconfig_accepts_file(tmp_path, provisioner_module):
     """Regular file mount should pass readiness wait."""
-    provisioner_module = _load_provisioner_module()
     kubeconfig_file = tmp_path / "config"
     kubeconfig_file.write_text("apiVersion: v1\n")
 
@@ -45,9 +28,8 @@ def test_wait_for_kubeconfig_accepts_file(tmp_path):
     provisioner_module._wait_for_kubeconfig(timeout=1)
 
 
-def test_init_k8s_client_rejects_directory_path(tmp_path):
+def test_init_k8s_client_rejects_directory_path(tmp_path, provisioner_module):
     """KUBECONFIG_PATH that resolves to a directory should be rejected."""
-    provisioner_module = _load_provisioner_module()
     kubeconfig_dir = tmp_path / "config_dir"
     kubeconfig_dir.mkdir()
 
@@ -60,9 +42,8 @@ def test_init_k8s_client_rejects_directory_path(tmp_path):
         assert "expected a file" in str(exc)
 
 
-def test_init_k8s_client_uses_file_kubeconfig(tmp_path, monkeypatch):
+def test_init_k8s_client_uses_file_kubeconfig(tmp_path, monkeypatch, provisioner_module):
     """When file exists, provisioner should load kubeconfig file path."""
-    provisioner_module = _load_provisioner_module()
     kubeconfig_file = tmp_path / "config"
     kubeconfig_file.write_text("apiVersion: v1\n")
 
@@ -90,9 +71,8 @@ def test_init_k8s_client_uses_file_kubeconfig(tmp_path, monkeypatch):
     assert result == "core-v1"
 
 
-def test_init_k8s_client_falls_back_to_incluster_when_missing(tmp_path, monkeypatch):
+def test_init_k8s_client_falls_back_to_incluster_when_missing(tmp_path, monkeypatch, provisioner_module):
     """When kubeconfig file is missing, in-cluster config should be attempted."""
-    provisioner_module = _load_provisioner_module()
     missing_path = tmp_path / "missing-config"
 
     calls: dict[str, int] = {"incluster": 0}