fix: Parallel unit test runner with file-level subprocess isolation (#3285)

* fix: parallel unit test runner with file-level subprocess isolation

- Rewrite test/run_all_test.py as file-level parallel runner using
  ThreadPoolExecutor with configurable workers (NEXENT_PYTEST_WORKERS)
  and per-file timeout (NEXENT_PYTEST_FILE_TIMEOUT)
- Add pytest-xdist to backend test extras
- Fix test_mcp_service.py: clear proxy env vars (socks://) in fixture
  to prevent httpx.AsyncClient ValueError
- Fix test_remote_mcp_service.py: mock check_runtime_host_port_available
  to prevent port conflict in container enable test
- Fix test_openai_llm.py: reduce memory leak from repeated module imports
- Update CI workflow: default to parallel mode, add dispatch inputs for
  worker count and per-file timeout

Serial: 229/229 pass (7m7s). Parallel: 229/229 pass (1m1s, ~7x speedup).

* chore: remove unused pytest-xdist dependency

The parallel runner uses ThreadPoolExecutor with per-file subprocess
isolation, not pytest-xdist. The xdist package was added but never
used due to sys.modules mock conflicts during pytest collection.

---------

Co-authored-by: Jinglong Wang <wangjinglong8@huawei.com>

Author: JasonW404

.github/workflows/auto-unit-test.yml

@@ -11,6 +11,14 @@ on:
         description: 'runner array in json format (e.g. ["ubuntu-latest"] or ["self-hosted"])'
         required: false
         default: '["ubuntu-24.04-arm"]'
+      pytest_workers:
+        description: 'parallel test workers (auto=CPU count, 0=serial, N=fixed count)'
+        required: false
+        default: 'auto'
+      pytest_file_timeout:
+        description: 'per-file timeout in seconds (0=disabled)'
+        required: false
+        default: '300'
   pull_request:
     branches: [develop, 'release/**', 'hotfix/**']
     paths:
@@ -49,23 +57,25 @@ jobs:
           cd ..
 
       - name: Run all tests and collect coverage
+        env:
+          NEXENT_PYTEST_WORKERS: ${{ github.event.inputs.pytest_workers || 'auto' }}
+          NEXENT_PYTEST_FILE_TIMEOUT: ${{ github.event.inputs.pytest_file_timeout || '300' }}
         run: |
           source backend/.venv/bin/activate && python test/run_all_test.py
           TEST_EXIT_CODE=$?
 
           if [ -f "test/coverage.xml" ]; then
-            echo "✅ Coverage XML file generated successfully."
+            echo "Coverage XML file generated successfully."
           else
-            echo "❌ Coverage XML file not found."
+            echo "Coverage XML file not found."
             exit 1
           fi
 
-          # Check if tests actually passed
           if [ $TEST_EXIT_CODE -ne 0 ]; then
-            echo "❌ Tests failed with exit code $TEST_EXIT_CODE"
+            echo "Tests failed with exit code $TEST_EXIT_CODE"
             exit $TEST_EXIT_CODE
           else
-            echo "✅ All tests passed successfully."
+            echo "All tests passed successfully."
           fi
 
       - name: Upload coverage to Codecov

test/backend/services/test_mcp_service.py

@@ -158,10 +158,23 @@ def __init__(self, name, description, inputSchema, outputSchema=None):
 mcp_service.ToolResult = RealToolResult
 
 
+# Proxy env vars that can leak into httpx.AsyncClient and cause failures
+# (e.g. socks:// proxies that httpx does not support natively)
+_PROXY_ENV_KEYS = [
+    "HTTP_PROXY", "HTTPS_PROXY", "http_proxy", "https_proxy",
+    "ALL_PROXY", "all_proxy", "NO_PROXY", "no_proxy",
+]
+
+
 # Reset global state before each test
 @pytest.fixture(autouse=True)
 def reset_global_state():
     """Reset global state before each test"""
+    saved_proxy = {}
+    for key in _PROXY_ENV_KEYS:
+        if key in os.environ:
+            saved_proxy[key] = os.environ.pop(key)
+
     # Reset before test
     mcp_service._openapi_mcp_services = {}
     mcp_service._mcp_management_app = None
@@ -182,6 +195,8 @@ def reset_global_state():
 
     yield
 
+    os.environ.update(saved_proxy)
+
     # Reset after test
     mcp_service._openapi_mcp_services = {}
     mcp_service._mcp_management_app = None

test/backend/services/test_remote_mcp_service.py

@@ -526,14 +526,15 @@ async def test_non_container_enable_without_custom_headers(
             custom_headers=None,
         )
 
+    @patch('backend.services.remote_mcp_service.check_runtime_host_port_available', return_value=True)
     @patch('backend.services.remote_mcp_service.update_mcp_record_enabled_by_id')
     @patch('backend.services.remote_mcp_service.update_mcp_record_container_fields_by_id')
     @patch('backend.services.remote_mcp_service.mcp_server_health')
     @patch('backend.services.remote_mcp_service.MCPContainerManager')
     @patch('backend.services.remote_mcp_service.get_mcp_record_by_id_and_tenant')
     @patch('backend.services.remote_mcp_service.get_mcp_records_by_tenant')
     async def test_container_enable_with_custom_headers(
-        self, mock_records, mock_get, mock_mgr_cls, mock_health, mock_cont_fields, mock_enabled
+        self, mock_records, mock_get, mock_mgr_cls, mock_health, mock_cont_fields, mock_enabled, mock_port_check
     ):
         """Test container enable with custom_headers passed to health check."""
         mock_get.return_value = self._make_record(