some fixes

tests/conftest.py

@@ -87,11 +87,19 @@ def populated_db_b4w(
     Only the first-layer ingestion table is filled; no further processing.
     ``**kwargs`` are forwarded to ``B4wExportFactory.build``; callable values
     are resolved per row (e.g. ``ValDt=lambda: faker.date_between(...)``).
+    ``Id1`` is reserved: it is set per row (``1..row_count``) and cannot be
+    overridden via ``**kwargs``.
+    The returned session is *not* closed by the fixture; close it in the test.
     """
 
     def populate_db_b4w(
         name: str, row_count: int = DEFAULT_B4W_ROWS, **kwargs: Any
     ) -> Session:
+        if "Id1" in kwargs:
+            raise ValueError(
+                "Id1 is set per row (1..row_count) by populated_db_b4w and "
+                "cannot be overridden via **kwargs"
+            )
         session = db_session_factory(name)
         for i in range(row_count):
             row_kwargs = {k: (v() if callable(v) else v) for k, v in kwargs.items()}