extract-and-test

Extract & Test — pywin32_adapter.py

Apply this skill whenever a method in src/solidworks_mcp/adapters/pywin32_adapter.py contains:

• Deeply nested try/except blocks or inner closures that can't be tested in isolation
• Mixed concerns (COM selection strategy + fallback + error handling all in one body)
• A closure that calls self._attempt(...) with an inner _run/_operation lambda

---

Step 1 — Read and Analyse

Read the target line range. For each logical block, fill in this table:

Concern	COM calls involved	Failure mode	Return contract
(fill in)	(fill in)	(fill in)	(fill in)

Apply these heuristics to determine the right helper shape:

Shape	When to use
-> None (log, never raise)	Setup/orientation side-effects — failure is acceptable
-> bool	COM operation that writes a file; True = file exists
-> dict | None	COM selection/query strategy; None = this strategy failed, try next
-> dict (raises on failure)	Last-chance fallback or invoker — surface error to caller
@staticmethod	Pure string/data transformation with no self state

---

Step 2 — Extract Helpers

Write one helper per concern. Insert helpers immediately before the async def they support.

def _<verb>_<noun>(self, <args>) -> <return type>:
    """<One-line description>.

    Args:
        <arg>: <description>

    Returns:
        <type>: <description>

    Raises:
        <ExceptionType>: <when>
    """
    ...

Examples by return contract:

# Graceful-failure helper — log, never raise
def _set_view_orientation(self, target_doc, orientation, view_const) -> None:
    try:
        target_doc.ShowNamedView2("", view_const)
    except Exception:
        logger.warning("Could not set view orientation to %s", orientation)

# Boolean helper — True = file written
def _save_screenshot_with_modelview(self, model_view, path, width, height) -> bool:
    try:
        model_view.SaveBitmapWithVariableSize(path, width, height)
        return os.path.exists(path)
    except Exception:
        return False

# Optional-dict helper — None = strategy failed, try next
def _try_select_by_extension(self, target_doc, candidates, feature_name) -> dict | None:
    for candidate in candidates:
        for entity_type in ENTITY_TYPES:
            try:
                if target_doc.Extension.SelectByID2(candidate, entity_type, 0, 0, 0, False, 0, None, 0):
                    return {"selected": True, "feature_name": feature_name, ...}
            except Exception:
                continue
    return None

# Raising helper — last-chance invoker
def _invoke_run_macro2(self, macro_path, module_name, proc_name) -> dict:
    result = self.swApp.RunMacro2(macro_path, module_name, proc_name, 0, 0)
    success = result[0] if isinstance(result, (list, tuple)) else bool(result)
    if not success:
        raise SolidWorksMCPError(f"RunMacro2 failed for {macro_path}")
    return {"macro_path": macro_path, "module_name": module_name}