feat(dbapi): validate max_total_rows at Connection boundary

Forward validation to the client-layer helper so both sync and async
DBAPI Connection constructors reject zero/negative/non-int values
up front.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: antoineleclair

src/dqlitedbapi/aio/connection.py

@@ -7,6 +7,7 @@
 
 import dqliteclient.exceptions as _client_exc
 from dqliteclient import DqliteConnection
+from dqliteclient.protocol import _validate_max_total_rows
 from dqlitedbapi.aio.cursor import AsyncCursor
 from dqlitedbapi.exceptions import InterfaceError, OperationalError, ProgrammingError
 
@@ -37,7 +38,7 @@ def __init__(
         self._address = address
         self._database = database
         self._timeout = timeout
-        self._max_total_rows = max_total_rows
+        self._max_total_rows = _validate_max_total_rows(max_total_rows)
         self._async_conn: DqliteConnection | None = None
         self._closed = False
         # asyncio primitives MUST be created inside the loop they will

src/dqlitedbapi/connection.py

@@ -10,6 +10,7 @@
 
 import dqliteclient.exceptions as _client_exc
 from dqliteclient import DqliteConnection
+from dqliteclient.protocol import _validate_max_total_rows
 from dqlitedbapi.cursor import Cursor
 from dqlitedbapi.exceptions import InterfaceError, OperationalError, ProgrammingError
 
@@ -82,7 +83,7 @@ def __init__(
         self._address = address
         self._database = database
         self._timeout = timeout
-        self._max_total_rows = max_total_rows
+        self._max_total_rows = _validate_max_total_rows(max_total_rows)
         self._async_conn: DqliteConnection | None = None
         self._closed = False
         self._loop: asyncio.AbstractEventLoop | None = None

tests/test_max_total_rows_validation.py

@@ -0,0 +1,46 @@
+"""Validation of the ``max_total_rows`` constructor parameter (DB-API)."""
+
+import pytest
+
+from dqlitedbapi import Connection
+from dqlitedbapi.aio import AsyncConnection
+
+
+class TestConnectionValidation:
+    def test_zero_rejected(self) -> None:
+        with pytest.raises(ValueError):
+            Connection("localhost:19001", max_total_rows=0)
+
+    def test_negative_rejected(self) -> None:
+        with pytest.raises(ValueError):
+            Connection("localhost:19001", max_total_rows=-10)
+
+    def test_bool_rejected(self) -> None:
+        with pytest.raises(TypeError):
+            Connection("localhost:19001", max_total_rows=True)  # type: ignore[arg-type]
+
+    def test_string_rejected(self) -> None:
+        with pytest.raises(TypeError):
+            Connection("localhost:19001", max_total_rows="100")  # type: ignore[arg-type]
+
+    def test_none_allowed(self) -> None:
+        conn = Connection("localhost:19001", max_total_rows=None)
+        assert conn._max_total_rows is None
+
+
+class TestAsyncConnectionValidation:
+    def test_zero_rejected(self) -> None:
+        with pytest.raises(ValueError):
+            AsyncConnection("localhost:19001", max_total_rows=0)
+
+    def test_negative_rejected(self) -> None:
+        with pytest.raises(ValueError):
+            AsyncConnection("localhost:19001", max_total_rows=-10)
+
+    def test_bool_rejected(self) -> None:
+        with pytest.raises(TypeError):
+            AsyncConnection("localhost:19001", max_total_rows=True)  # type: ignore[arg-type]
+
+    def test_none_allowed(self) -> None:
+        conn = AsyncConnection("localhost:19001", max_total_rows=None)
+        assert conn._max_total_rows is None