diff --git a/packages/modelaudit-picklescan/src/modelaudit_picklescan/call_graph.py b/packages/modelaudit-picklescan/src/modelaudit_picklescan/call_graph.py
index ab1039e73..629bb203f 100644
--- a/packages/modelaudit-picklescan/src/modelaudit_picklescan/call_graph.py
+++ b/packages/modelaudit-picklescan/src/modelaudit_picklescan/call_graph.py
@@ -59,7 +59,8 @@
 
 
 class _CacheClearable(Protocol):
-    def cache_clear(self) -> None: ...
+    def cache_clear(self) -> None:
+        pass
 
 
 _SOURCE_SENSITIVE_CACHED_FUNCTIONS: set[_CacheClearable] = set()
diff --git a/tests/conftest.py b/tests/conftest.py
index 2bbdba41a..7d4e89b5b 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -37,6 +37,11 @@
 }
 _FRAMEWORK_AVAILABILITY: dict[str, bool] = {}
 
+# Reduced CI lanes only install the dependency set needed for this curated test
+# subset. Keep this centralized so adding a supported Python version requires one
+# deliberate update instead of duplicating version checks in hook logic.
+RESTRICTED_PYTHON_VERSIONS = frozenset({(3, 10), (3, 12), (3, 13)})
+
 
 def _check_framework(name: str) -> bool:
     """Check whether a framework package can be imported, with lazy caching."""
@@ -80,8 +85,8 @@ def _detect_symlink_support() -> bool:
 
 def pytest_runtest_setup(item):
     """Skip tests based on Python version and framework availability."""
-    # Skip problematic tests on Python 3.10, 3.12, and 3.13 to ensure CI passes
-    if sys.version_info[:2] in [(3, 10), (3, 12), (3, 13)]:
+    # Skip problematic tests on restricted Python versions to ensure CI passes
+    if sys.version_info[:2] in RESTRICTED_PYTHON_VERSIONS:
         test_file = str(item.fspath)
 
         # Only allow core XGBoost scanner tests and basic unit tests on problematic Python versions
@@ -301,20 +306,21 @@ def temp_model_dir(tmp_path):
 
 
 @pytest.fixture
-def mock_progress_callback():
-    """Return a mock progress callback function that records calls."""
-    progress_messages = []
-    progress_percentages = []
+def mock_progress_callback() -> "ProgressCallbackRecorder":
+    """Return a mock progress callback object that records calls."""
+    return ProgressCallbackRecorder()
+
 
-    def progress_callback(message, percentage):
-        progress_messages.append(message)
-        progress_percentages.append(percentage)
+class ProgressCallbackRecorder:
+    """Record progress callback calls for assertions in integration tests."""
 
-    # Add the recorded messages and percentages as attributes
-    progress_callback.messages = progress_messages  # type: ignore[attr-defined]
-    progress_callback.percentages = progress_percentages  # type: ignore[attr-defined]
+    def __init__(self) -> None:
+        self.messages: list[str] = []
+        self.percentages: list[float] = []
 
-    return progress_callback
+    def __call__(self, message: str, percentage: float) -> None:
+        self.messages.append(message)
+        self.percentages.append(percentage)
 
 
 @pytest.fixture
@@ -415,7 +421,16 @@ def pytest_configure_node(node: Any) -> None:
     global _xdist_status_reporter
 
     if _xdist_status_reporter is None:
-        status_dir = node.config._tmp_path_factory.mktemp("modelaudit-pytest-xdist")  # type: ignore[attr-defined]
+        # pytest does not expose a public API at this xdist hook point for creating
+        # a controller-owned temp directory. Pytest 8.4+ provides this internal
+        # factory; fail clearly if a future pytest release removes it.
+        tmp_path_factory = getattr(node.config, "_tmp_path_factory", None)
+        if tmp_path_factory is None:
+            raise RuntimeError(
+                "pytest internal API changed: '_tmp_path_factory' is unavailable in pytest_configure_node"
+            )
+
+        status_dir = tmp_path_factory.mktemp("modelaudit-pytest-xdist")
         _xdist_status_reporter = XdistWorkerStatusReporter.from_environment(status_dir)
         if _xdist_status_reporter is None:
             return