feat: add fetchone, fetchall, fetchval convenience methods to ConnectionPool

The pool had execute() and fetch() but not fetchone(), fetchall(), or
fetchval(), forcing users to drop to acquire() for these operations.
Add the three missing methods for API consistency with DqliteConnection,
matching the pattern used by asyncpg's Pool.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: antoineleclair

src/dqliteclient/pool.py

@@ -221,6 +221,23 @@ async def fetch(self, sql: str, params: Sequence[Any] | None = None) -> list[dic
         async with self.acquire() as conn:
             return await conn.fetch(sql, params)
 
+    async def fetchone(
+        self, sql: str, params: Sequence[Any] | None = None
+    ) -> dict[str, Any] | None:
+        """Execute a query and return the first result using a pooled connection."""
+        async with self.acquire() as conn:
+            return await conn.fetchone(sql, params)
+
+    async def fetchall(self, sql: str, params: Sequence[Any] | None = None) -> list[list[Any]]:
+        """Execute a query and return results as lists using a pooled connection."""
+        async with self.acquire() as conn:
+            return await conn.fetchall(sql, params)
+
+    async def fetchval(self, sql: str, params: Sequence[Any] | None = None) -> Any:
+        """Execute a query and return a single value using a pooled connection."""
+        async with self.acquire() as conn:
+            return await conn.fetchval(sql, params)
+
     async def close(self) -> None:
         """Close the pool and all idle connections.
 

tests/test_pool.py

@@ -817,3 +817,36 @@ async def test_fetch_through_pool(self, mock_connection: MagicMock) -> None:
             assert result == [{"id": 1}]
 
         await pool.close()
+
+    async def test_fetchone_through_pool(self, mock_connection: MagicMock) -> None:
+        mock_connection.fetchone = AsyncMock(return_value={"id": 1})
+        pool = ConnectionPool(["localhost:9001"])
+
+        with patch.object(pool._cluster, "connect", return_value=mock_connection):
+            await pool.initialize()
+            result = await pool.fetchone("SELECT * FROM t LIMIT 1")
+            assert result == {"id": 1}
+
+        await pool.close()
+
+    async def test_fetchall_through_pool(self, mock_connection: MagicMock) -> None:
+        mock_connection.fetchall = AsyncMock(return_value=[[1, "a"], [2, "b"]])
+        pool = ConnectionPool(["localhost:9001"])
+
+        with patch.object(pool._cluster, "connect", return_value=mock_connection):
+            await pool.initialize()
+            result = await pool.fetchall("SELECT * FROM t")
+            assert result == [[1, "a"], [2, "b"]]
+
+        await pool.close()
+
+    async def test_fetchval_through_pool(self, mock_connection: MagicMock) -> None:
+        mock_connection.fetchval = AsyncMock(return_value=42)
+        pool = ConnectionPool(["localhost:9001"])
+
+        with patch.object(pool._cluster, "connect", return_value=mock_connection):
+            await pool.initialize()
+            result = await pool.fetchval("SELECT count(*) FROM t")
+            assert result == 42
+
+        await pool.close()