test: catch backtick and bracket-quoted table names in self-scan

- UPDATE pattern alternative corrected (UPDATE ... children, not
  UPDATE SET)
- allowlist comparison uses as_posix() so Windows separators cannot
  make the DAO itself appear as an offender

custom_components/nestquest/__init__.py

@@ -10,6 +10,9 @@ from homeassistant.config_entries import ConfigEntry
 from homeassistant.core import HomeAssistant
 
 from .const import DOMAIN, LOGGER
+from .db import NestQuestDatabase
+from .migrations import apply_migrations
+from .store import async_get_db_path
 
 _LOGGER = LOGGER
 
@@ -20,6 +23,7 @@ class NestQuestRuntimeData:
 
     entry_id: str
     options: dict[str, Any]
+    database: NestQuestDatabase
     remove_update_listener: Callable[[], Any]
 
 
@@ -31,6 +35,14 @@ async def async_setup(hass: HomeAssistant, config: dict[str, Any]) -> bool:
 async def async_setup_entry(hass: HomeAssistant, entry: ConfigEntry) -> bool:
     """Set up NestQuest from a config entry."""
     hass.data.setdefault(DOMAIN, {})
+    existing = hass.data[DOMAIN].get(entry.entry_id)
+    if existing is not None:
+        db = getattr(existing, "database", None)
+        if db is None:
+            db = await NestQuestDatabase(hass).open(await async_get_db_path(hass))
+            existing.database = db
+        entry.runtime_data = existing
+        return True
 
     async def _async_update_listener(
         listener_hass: HomeAssistant, listener_entry: ConfigEntry
@@ -38,10 +50,18 @@ async def async_setup_entry(hass: HomeAssistant, entry: ConfigEntry) -> bool:
         """Reload the entry when its options change."""
         await listener_hass.config_entries.async_reload(listener_entry.entry_id)
 
+    database = await NestQuestDatabase(hass).open(await async_get_db_path(hass))
+    try:
+        await apply_migrations(database)
+        remove_update_listener = entry.add_update_listener(_async_update_listener)
+    except BaseException:
+        await database.close()
+        raise
     runtime_data = NestQuestRuntimeData(
         entry_id=entry.entry_id,
         options=dict(entry.options),
-        remove_update_listener=entry.add_update_listener(_async_update_listener),
+        database=database,
+        remove_update_listener=remove_update_listener,
     )
     entry.runtime_data = runtime_data
     hass.data[DOMAIN][entry.entry_id] = runtime_data
@@ -58,10 +78,22 @@ async def async_unload_entry(hass: HomeAssistant, entry: ConfigEntry) -> bool:
         runtime_data = getattr(entry, "runtime_data", None)
     if runtime_data is not None:
         remove_update_listener = getattr(runtime_data, "remove_update_listener", None)
-        if remove_update_listener is not None:
-            result = remove_update_listener()
-            if inspect.isawaitable(result):
-                await result
+        unload_error: BaseException | None = None
+        try:
+            if remove_update_listener is not None:
+                result = remove_update_listener()
+                if inspect.isawaitable(result):
+                    await result
+        except BaseException as err:
+            unload_error = err
+        finally:
+            database = getattr(runtime_data, "database", None)
+            if database is not None:
+                await database.close()
+        if unload_error is not None:
+            if getattr(entry, "runtime_data", None) is not None:
+                entry.runtime_data = None
+            raise unload_error
     if getattr(entry, "runtime_data", None) is not None:
         entry.runtime_data = None
     return True

custom_components/nestquest/dao_children.py

@@ -0,0 +1,289 @@
+"""Typed DAO layer for the children and admin_users tables.
+
+All SQL for ``children`` and ``admin_users`` lives in this module per
+the feature guardrail: callers get typed dataclasses back and never see
+raw rows or SQL.  Every method is async and runs through
+:class:`~.db.NestQuestDatabase`, so each statement executes on the HA
+executor and the event loop never blocks.
+
+Error contract: violations surface as the underlying
+:class:`sqlite3.IntegrityError` (duplicate, foreign-key, or CHECK
+failure) from the execute call; the DAO adds no wrapping exception
+type.  A get that matches nothing returns ``None``; a mutation that
+matches nothing is reported by :class:`~.db.ExecutionResult.rowcount`,
+which each method returns where the caller may need it (reorder, and
+the admin remove/set paths).
+"""
+from __future__ import annotations
+
+import asyncio
+from dataclasses import dataclass
+
+from .db import NestQuestDatabase
+
+
+@dataclass(frozen=True)
+class ChildRecord:
+    """One row of ``children``."""
+
+    id: int
+    display_name: str
+    colour: str | None
+    avatar_ref: str | None
+    sort_order: int
+    is_active: bool
+    created_at: str
+
+
+@dataclass(frozen=True)
+class AdminUserRecord:
+    """One row of ``admin_users``."""
+
+    ha_user_id: str
+    added_at: str
+
+
+def _child_from_row(row: tuple) -> ChildRecord:
+    """Build a :class:`ChildRecord` from a SELECT row."""
+    return ChildRecord(
+        id=row[0],
+        display_name=row[1],
+        colour=row[2],
+        avatar_ref=row[3],
+        sort_order=row[4],
+        is_active=bool(row[5]),
+        created_at=row[6],
+    )
+
+
+_CHILD_COLUMNS = (
+    "id, display_name, colour, avatar_ref, sort_order, is_active, created_at"
+)
+
+
+#: One asyncio.Lock per (connection wrapper, running loop), shared by
+#: every ChildrenDao instance over the same database: the wrapper
+#: rejects a second concurrent transaction with RuntimeError, so ALL
+#: transactional DAO operations on one connection must queue here, not
+#: per-instance.  Keyed like the migration runner's lock; entries are
+#: never evicted (a config entry holds one wrapper per process).
+_CONNECTION_LOCKS: dict[tuple[int, int], asyncio.Lock] = {}
+
+
+def _connection_lock(database) -> asyncio.Lock:
+    """Return the shared transaction-serializing lock for ``database``."""
+    loop = asyncio.get_running_loop()
+    key = (id(database), id(loop))
+    lock = _CONNECTION_LOCKS.get(key)
+    if lock is None:
+        lock = asyncio.Lock()
+        _CONNECTION_LOCKS[key] = lock
+    return lock
+
+
+class ChildrenDao:
+    """Typed async data access for the ``children`` table.
+
+    Deletion is deliberately absent: children are deactivated, never
+    deleted, because completion history references them (feature
+    guardrail).
+    """
+
+    def __init__(self, database) -> None:
+        self._database = database
+
+    async def create(
+        self,
+        display_name: str,
+        created_at: str,
+        *,
+        colour: str | None = None,
+        avatar_ref: str | None = None,
+        sort_order: int = 0,
+        is_active: bool = True,
+    ) -> ChildRecord:
+        """Insert one child and return the record as stored."""
+        result = await self._database.execute(
+            "INSERT INTO children (display_name, colour, avatar_ref, "
+            "sort_order, is_active, created_at) VALUES (?, ?, ?, ?, ?, ?)",
+            (
+                display_name,
+                colour,
+                avatar_ref,
+                sort_order,
+                int(is_active),
+                created_at,
+            ),
+        )
+        child = await self.get(result.lastrowid)
+        assert child is not None
+        return child
+
+    async def get(self, child_id: int) -> ChildRecord | None:
+        """Return the child with ``child_id``, or None."""
+        row = await self._database.fetch_one(
+            f"SELECT {_CHILD_COLUMNS} FROM children WHERE id = ?",
+            (child_id,),
+        )
+        return _child_from_row(row) if row is not None else None
+
+    async def list_active(self) -> list[ChildRecord]:
+        """Return active children ordered by sort_order, then id."""
+        rows = await self._database.fetch_all(
+            f"SELECT {_CHILD_COLUMNS} FROM children WHERE is_active = 1 "
+            "ORDER BY sort_order, id"
+        )
+        return [_child_from_row(row) for row in rows]
+
+    async def list_all(self) -> list[ChildRecord]:
+        """Return all children ordered by sort_order, then id."""
+        rows = await self._database.fetch_all(
+            f"SELECT {_CHILD_COLUMNS} FROM children "
+            "ORDER BY sort_order, id"
+        )
+        return [record for record in map(_child_from_row, rows)]
+
+    async def update(
+        self,
+        child_id: int,
+        *,
+        display_name: str | None = None,
+        colour: str | None = None,
+        avatar_ref: str | None = None,
+        sort_order: int | None = None,
+    ) -> int:
+        """Update the given fields; returns rows updated (0 if absent).
+
+        Only non-None arguments are written, so a caller cannot
+        accidentally blank a column by omitting it.
+        """
+        assignments: list[str] = []
+        parameters: list[object] = []
+        if display_name is not None:
+            assignments.append("display_name = ?")
+            parameters.append(display_name)
+        if colour is not None:
+            assignments.append("colour = ?")
+            parameters.append(colour)
+        if avatar_ref is not None:
+            assignments.append("avatar_ref = ?")
+            parameters.append(avatar_ref)
+        if sort_order is not None:
+            assignments.append("sort_order = ?")
+            parameters.append(sort_order)
+        if not assignments:
+            return 0
+        parameters.append(child_id)
+        result = await self._database.execute(
+            f"UPDATE children SET {', '.join(assignments)} WHERE id = ?",
+            tuple(parameters),
+        )
+        return result.rowcount
+
+    async def set_active(self, child_id: int, is_active: bool) -> int:
+        """Set the child's active flag; returns rows updated (0 if absent)."""
+        result = await self._database.execute(
+            "UPDATE children SET is_active = ? WHERE id = ?",
+            (int(is_active), child_id),
+        )
+        return result.rowcount
+
+    async def reorder(self, ordered_ids: list[int]) -> None:
+        """Persist a new sort order: ``ordered_ids[i]`` gets sort_order i.
+
+        Runs inside one transaction; positions are staged at offset
+        -len (all negative, so any permutation of the same ids never
+        collides mid-reorder under the wrapper's single-connection
+        serialization), then finalized 0..n-1.  Duplicate ids are
+        rejected up front: they cannot all hold distinct positions, and
+        silently assigning the last occurrence's index would hide a
+        caller bug.
+
+        Concurrent reorder() calls on one connection are serialized by
+        a connection-scoped asyncio lock (shared across every ChildrenDao
+        over the same wrapper, however many instances): the wrapper's
+        transaction() rejects a second concurrent transaction with
+        RuntimeError, so racing callers would crash instead of
+        queueing.  The lock makes the second call wait, then run
+        against the first call's final state.
+        """
+        if not ordered_ids:
+            return
+        if len(set(ordered_ids)) != len(ordered_ids):
+            raise ValueError(
+                "reorder() received duplicate child ids; every id must "
+                "appear at most once"
+            )
+        async with _connection_lock(self._database):
+            async with self._database.transaction():
+                offset = len(ordered_ids)
+                await self._database.execute_many(
+                    "UPDATE children SET sort_order = ? WHERE id = ?",
+                    [
+                        (-(offset + index), child_id)
+                        for index, child_id in enumerate(ordered_ids)
+                    ],
+                )
+                await self._database.execute_many(
+                    "UPDATE children SET sort_order = ? WHERE id = ?",
+                    [
+                        (index, child_id)
+                        for index, child_id in enumerate(ordered_ids)
+                    ],
+                )
+
+
+class AdminUsersDao:
+    """Typed async access to the ``admin_users`` allowlist.
+
+    The allowlist stores HA user IDs, never usernames (feature
+    guardrail); an empty allowlist means no admin, enforced by callers
+    resolving through :meth:`exists`.
+    """
+
+    def __init__(self, database) -> None:
+        self._database = database
+
+    async def add(self, ha_user_id: str, added_at: str) -> bool:
+        """Add a user to the allowlist; True if inserted, False if present.
+
+        Idempotent under concurrency: a single INSERT ... ON CONFLICT DO
+        NOTHING decides and inserts in one statement (the wrapper
+        serializes statements, not check-then-insert sequences, so a
+        SELECT/INSERT pair would let two concurrent adds both see no
+        row and the second one raise IntegrityError).  rowcount reports
+        whether the insert actually happened.
+        """
+        result = await self._database.execute(
+            "INSERT INTO admin_users (ha_user_id, added_at) VALUES (?, ?) "
+            "ON CONFLICT (ha_user_id) DO NOTHING",
+            (ha_user_id, added_at),
+        )
+        return result.rowcount > 0
+
+    async def remove(self, ha_user_id: str) -> bool:
+        """Remove a user from the allowlist; True if a row was removed."""
+        result = await self._database.execute(
+            "DELETE FROM admin_users WHERE ha_user_id = ?",
+            (ha_user_id,),
+        )
+        return result.rowcount > 0
+
+    async def list(self) -> list[AdminUserRecord]:
+        """Return every allowlisted user, oldest first."""
+        rows = await self._database.fetch_all(
+            "SELECT ha_user_id, added_at FROM admin_users "
+            "ORDER BY added_at, ha_user_id"
+        )
+        return [
+            AdminUserRecord(ha_user_id=row[0], added_at=row[1])
+            for row in rows
+        ]
+
+    async def exists(self, ha_user_id: str) -> bool:
+        """Return True if ``ha_user_id`` is allowlisted."""
+        row = await self._database.fetch_one(
+            "SELECT 1 FROM admin_users WHERE ha_user_id = ?",
+            (ha_user_id,),
+        )
+        return row is not None

custom_components/nestquest/db.py

@@ -0,0 +1,422 @@
+"""Async SQLite connection wrapper for the NestQuest integration."""
+from __future__ import annotations
+
+import asyncio
+import sqlite3
+from collections.abc import AsyncIterator, Awaitable, Sequence
+from contextlib import asynccontextmanager
+from dataclasses import dataclass
+from pathlib import Path
+from typing import Any
+
+from homeassistant.core import HomeAssistant
+
+
+@dataclass(frozen=True)
+class ExecutionResult:
+    """Plain-data outcome of one statement.
+
+    ``rowcount`` and ``lastrowid`` mirror the corresponding
+    :class:`sqlite3.Cursor` attributes; both are captured on the executor
+    thread so no sqlite3 object ever crosses back to the event loop.
+    """
+
+    rowcount: int
+    lastrowid: int | None
+
+
+class NestQuestDatabase:
+    """Async wrapper around a single SQLite connection.
+
+    Every sqlite3 call is delegated to the Home Assistant executor through
+    ``hass.async_add_executor_job`` so the event loop is never blocked, and
+    only plain Python data (row tuples and :class:`ExecutionResult`) is
+    returned to the event loop.
+
+    Every operation is serialized through one asyncio.Lock per wrapper.  A
+    ``transaction()`` holds that lock for its whole BEGIN..COMMIT span, so
+    interleaved coroutines cannot corrupt the transaction and concurrent
+    BEGINs are impossible; statements issued while a transaction is open
+    queue until it completes.  Concurrent transactions on one wrapper are
+    not supported: a second ``transaction()`` entered while one is active
+    raises :class:`RuntimeError`.  ``close()`` serializes on the same lock
+    and is idempotent.
+
+    Every connection-affecting executor job (connect, pragmas, statements,
+    transaction lifecycle and close) is awaited through the settlement
+    helper :meth:`_await_settled`: if the awaiting task is cancelled while
+    a job is in flight, the job still settles on the worker thread before
+    the cancellation propagates, so the wrapper lock is never released
+    while the executor thread is mid-job.
+    """
+
+    def __init__(self, hass: HomeAssistant) -> None:
+        """Initialize the wrapper around a Home Assistant instance."""
+        self._hass = hass
+        self._conn: sqlite3.Connection | None = None
+        self._rowcount: int = -1
+        self._lastrowid: int | None = None
+        self._lock: asyncio.Lock | None = None
+        self._lock_loop: asyncio.AbstractEventLoop | None = None
+        self._in_transaction = False
+        self._tx_task: asyncio.Task | None = None
+
+    def _get_lock(self) -> asyncio.Lock:
+        """Return the per-wrapper lock, (re)bound to the running loop.
+
+        HA drives every wrapper call from one event loop, so the lock is
+        created once and reused; re-binding only when the running loop
+        differs keeps the wrapper usable from plain synchronous drivers
+        that run each call on a fresh loop.
+        """
+        loop = asyncio.get_running_loop()
+        if self._lock is None or self._lock_loop is not loop:
+            self._lock = asyncio.Lock()
+            self._lock_loop = loop
+        return self._lock
+
+    @property
+    def connected(self) -> bool:
+        """Return True while the underlying connection is open."""
+        return self._conn is not None
+
+    @property
+    def rowcount(self) -> int:
+        """Row count of the most recent statement, or -1 when unset."""
+        return self._rowcount
+
+    @property
+    def lastrowid(self) -> int | None:
+        """Row id of the most recent insert, or None when unset."""
+        return self._lastrowid
+
+    @asynccontextmanager
+    async def _serialized(self) -> AsyncIterator[None]:
+        """Hold the wrapper lock unless the caller owns the active transaction.
+
+        A transaction holds the lock for its whole BEGIN..COMMIT span;
+        statements issued by the transaction's own task are already
+        serialized by it and must not re-acquire the non-reentrant lock.
+        Any other task queues on the lock until the transaction ends.
+        """
+        if (
+            self._in_transaction
+            and self._tx_task is not None
+            and asyncio.current_task() is self._tx_task
+        ):
+            yield
+            return
+        async with self._get_lock():
+            yield
+
+    async def open(self, path: Path | str) -> NestQuestDatabase:
+        """Open the SQLite file with WAL journal mode and foreign keys on.
+
+        Cancellation-safe: if this call is cancelled while the connect job
+        is in flight, the job still settles (see :meth:`_await_settled`).
+        A connection the settled job created is never adopted by the
+        cancelled call; it is closed through a settled executor job instead
+        of being abandoned to garbage collection, and the cancellation
+        propagates afterwards, so a follow-up ``open()`` starts from a
+        clean state.
+        """
+        if self._conn is not None:
+            return self
+        async with self._get_lock():
+            if self._conn is not None:
+                return self
+
+            def _open() -> sqlite3.Connection:
+                conn = sqlite3.connect(
+                    path, check_same_thread=False, isolation_level=None
+                )
+                try:
+                    conn.execute("PRAGMA journal_mode=WAL")
+                    conn.execute("PRAGMA foreign_keys=ON")
+                except BaseException:
+                    conn.close()
+                    raise
+                return conn
+
+            settled, cancelled = await self._await_settled_state(
+                self._hass.async_add_executor_job(_open)
+            )
+            if cancelled:
+                if isinstance(settled, sqlite3.Connection):
+
+                    def _close_abandoned() -> None:
+                        settled.close()
+
+                    await self._await_settled(
+                        self._hass.async_add_executor_job(_close_abandoned)
+                    )
+                raise asyncio.CancelledError()
+            self._conn = settled
+        return self
+
+    async def execute(
+        self, sql: str, parameters: Sequence[Any] = ()
+    ) -> ExecutionResult:
+        """Run one statement in the executor and return its plain result."""
+        async with self._serialized():
+            conn = self._require_conn()
+
+            def _execute() -> ExecutionResult:
+                cursor = conn.execute(sql, parameters)
+                return ExecutionResult(cursor.rowcount, cursor.lastrowid)
+
+            result = await self._await_settled(
+                self._hass.async_add_executor_job(_execute)
+            )
+            self._rowcount = result.rowcount
+            self._lastrowid = result.lastrowid
+            return result
+
+    async def execute_many(
+        self, sql: str, parameters: Sequence[Sequence[Any]]
+    ) -> ExecutionResult:
+        """Run executemany in the executor and return its plain result."""
+        async with self._serialized():
+            conn = self._require_conn()
+
+            def _execute_many() -> ExecutionResult:
+                cursor = conn.executemany(sql, parameters)
+                return ExecutionResult(cursor.rowcount, cursor.lastrowid)
+
+            result = await self._await_settled(
+                self._hass.async_add_executor_job(_execute_many)
+            )
+            self._rowcount = result.rowcount
+            self._lastrowid = result.lastrowid
+            return result
+
+    async def fetch_one(
+        self, sql: str, parameters: Sequence[Any] = ()
+    ) -> tuple | None:
+        """Run a query in the executor and return its first row, or None."""
+        async with self._serialized():
+            conn = self._require_conn()
+
+            def _fetch_one() -> tuple[tuple | None, int, int | None]:
+                cursor = conn.execute(sql, parameters)
+                return cursor.fetchone(), cursor.rowcount, cursor.lastrowid
+
+            row, rowcount, lastrowid = await self._await_settled(
+                self._hass.async_add_executor_job(_fetch_one)
+            )
+            self._rowcount = rowcount
+            self._lastrowid = lastrowid
+            return row
+
+    async def fetch_all(
+        self, sql: str, parameters: Sequence[Any] = ()
+    ) -> list[tuple]:
+        """Run a query in the executor and return all of its rows."""
+        async with self._serialized():
+            conn = self._require_conn()
+
+            def _fetch_all() -> tuple[list[tuple], int, int | None]:
+                cursor = conn.execute(sql, parameters)
+                return cursor.fetchall(), cursor.rowcount, cursor.lastrowid
+
+            rows, rowcount, lastrowid = await self._await_settled(
+                self._hass.async_add_executor_job(_fetch_all)
+            )
+            self._rowcount = rowcount
+            self._lastrowid = lastrowid
+            return rows
+
+    @asynccontextmanager
+    async def transaction(self) -> AsyncIterator[None]:
+        """Run a block inside BEGIN/COMMIT, rolling back on any exception.
+
+        The wrapper lock is held for the entire BEGIN..COMMIT span, so no
+        other statement can interleave inside the transaction.  Entering a
+        second transaction while one is active raises RuntimeError.  A
+        failing COMMIT (e.g. a deferred foreign-key violation) also triggers
+        a ROLLBACK before the commit error propagates, so the real
+        connection is never left inside a stray transaction.
+
+        The lifecycle is cancellation-safe.  Transaction ownership and the
+        wrapper lock are only released after the executor work has fully
+        settled, even when the owning task is cancelled mid-flight: if a
+        cancelled BEGIN or COMMIT still completes on the worker thread,
+        the corresponding ROLLBACK is shielded and awaited before any state
+        is cleared.  A lifecycle statement that fails plus a failing
+        follow-up cleanup surface both errors in an ExceptionGroup.
+        """
+        if self._in_transaction:
+            raise RuntimeError(
+                "A NestQuest transaction is already active on this "
+                "connection; concurrent transactions are not supported"
+            )
+        async with self._get_lock():
+            conn = self._require_conn()
+            self._in_transaction = True
+            self._tx_task = asyncio.current_task()
+            try:
+
+                def _begin() -> None:
+                    conn.execute("BEGIN")
+
+                await self._settle_lifecycle(
+                    conn,
+                    self._hass.async_add_executor_job(_begin),
+                    "BEGIN did not settle cleanly and the follow-up "
+                    "cleanup also raised; the transaction may need manual "
+                    "cleanup",
+                )
+                try:
+                    yield
+                except BaseException:
+
+                    def _rollback() -> None:
+                        conn.execute("ROLLBACK")
+
+                    await self._settle_lifecycle(
+                        conn,
+                        self._hass.async_add_executor_job(_rollback),
+                        "ROLLBACK failed and the follow-up cleanup also "
+                        "raised; the transaction may need manual cleanup",
+                    )
+                    raise
+
+                def _commit() -> None:
+                    conn.execute("COMMIT")
+
+                await self._settle_lifecycle(
+                    conn,
+                    self._hass.async_add_executor_job(_commit),
+                    "COMMIT failed and the follow-up cleanup also raised; "
+                    "the transaction may need manual cleanup",
+                )
+            finally:
+                self._in_transaction = False
+                self._tx_task = None
+
+    async def _settle_lifecycle(
+        self, conn: sqlite3.Connection, job: Awaitable[Any], message: str
+    ) -> None:
+        """Run one BEGIN/ROLLBACK/COMMIT job, then force the connection clean.
+
+        The job always settles first (see :meth:`_await_settled`), so a
+        cancelled statement that the worker thread completed anyway is
+        never abandoned mid-flight.  If the job raised, a follow-up
+        ROLLBACK — itself settled — guarantees the connection ends outside
+        any SQLite transaction before the error propagates.  When both the
+        job and the cleanup raise, both errors are preserved in an
+        ExceptionGroup instead of the original being lost.
+        """
+        try:
+            await self._await_settled(job)
+        except BaseException as settle_error:
+            errors: list[BaseException] = [settle_error]
+            try:
+                await self._ensure_no_stray_transaction(conn)
+            except BaseException as cleanup_error:
+                errors.append(cleanup_error)
+            if len(errors) == 2:
+                raise BaseExceptionGroup(message, errors) from settle_error
+            raise
+
+    async def _ensure_no_stray_transaction(
+        self, conn: sqlite3.Connection
+    ) -> None:
+        """Force the connection out of any transaction via ROLLBACK.
+
+        Runs after a failed or cancelled lifecycle statement.  The worker
+        thread may still be finishing (or may already have completed) the
+        very statement whose await was cancelled, so both the check and
+        the ROLLBACK settle in the executor before the caller releases
+        transaction ownership.
+        """
+
+        def _cleanup() -> bool:
+            if conn.in_transaction:
+                conn.execute("ROLLBACK")
+            return conn.in_transaction
+
+        stray = await self._await_settled(
+            self._hass.async_add_executor_job(_cleanup)
+        )
+        if stray:
+            raise RuntimeError(
+                "The SQLite connection is still inside a transaction after "
+                "cleanup; the transaction may need manual cleanup"
+            )
+
+    async def _await_settled(self, job: Awaitable[Any]) -> Any:
+        """Await ``job``, letting it settle even if this task is cancelled.
+
+        Cancellation is observed, not swallowed: it is re-raised only once
+        the job has fully settled, so the caller can finalize against a
+        known connection state instead of abandoning in-flight work.  The
+        job is wrapped in a task because a bare coroutine dies un-awaited
+        once its await is cancelled.  A second cancellation during
+        settlement is absorbed the same way; if the job itself fails after
+        a cancellation, both errors surface in an ExceptionGroup.
+        """
+        result, cancelled = await self._await_settled_state(job)
+        if cancelled:
+            raise asyncio.CancelledError()
+        return result
+
+    async def _await_settled_state(self, job: Awaitable[Any]) -> tuple[Any, bool]:
+        """Await ``job`` to settlement and report ``(result, cancelled)``.
+
+        Same settlement guarantees as :meth:`_await_settled`, but returns
+        the settled outcome together with whether the awaiting task was
+        cancelled, so callers that must act on a settled result before
+        re-raising cancellation (e.g. closing an abandoned connection)
+        can do so without losing the result.
+        """
+        cancelled = False
+        inner = asyncio.ensure_future(job)
+        while not inner.done():
+            try:
+                await asyncio.shield(inner)
+            except asyncio.CancelledError:
+                cancelled = True
+        try:
+            result = inner.result()
+        except BaseException as job_error:
+            if cancelled:
+                raise BaseExceptionGroup(
+                    "executor job failed while settling after cancellation",
+                    [asyncio.CancelledError(), job_error],
+                ) from job_error
+            raise
+        return result, cancelled
+
+    async def close(self) -> None:
+        """Close the connection in the executor; safe to call repeatedly.
+
+        Serialized on the wrapper lock, so an in-flight operation or open
+        transaction always completes before the connection is closed.
+        """
+        if (
+            self._in_transaction
+            and self._tx_task is not None
+            and asyncio.current_task() is self._tx_task
+        ):
+            raise RuntimeError(
+                "Cannot close the NestQuest database from inside its own "
+                "transaction; exit the transaction first"
+            )
+        async with self._get_lock():
+            conn, self._conn = self._conn, None
+            self._rowcount, self._lastrowid = -1, None
+            if conn is None:
+                return
+
+            def _close() -> None:
+                conn.close()
+
+            await self._await_settled(self._hass.async_add_executor_job(_close))
+
+    def _require_conn(self) -> sqlite3.Connection:
+        if self._conn is None:
+            raise RuntimeError(
+                "The NestQuest database connection is closed; call open() first"
+            )
+        return self._conn

custom_components/nestquest/migrations.py

@@ -0,0 +1,236 @@
+"""Versioned schema migration runner for the NestQuest SQLite database.
+
+The runner owns one metadata table, ``nestquest_schema_version``, holding
+a single row with the schema version the database file currently
+reflects.  Migrations are declared as an ordered list: entry ``n``
+upgrades version ``n-1`` to version ``n``.  Applying a migration means
+running its DDL inside one transaction and stamping the new version in
+that same transaction, so a database never persists a half-applied
+migration: any failure rolls the statements and the version stamp back
+together, leaving the file at its prior version.
+
+Version 0 means "the file exists but carries no NestQuest schema yet"
+— a fresh file, or a file this integration has never written.  Starting
+the runner against version 0 applies migration 1, which applies the
+full v1 DDL from :mod:`.schema` and stamps version 1.
+
+Each migration's statements and its version stamp run inside ONE
+transaction, and the stamp is written as DELETE + INSERT rather than
+UPDATE because a version-0 database has no version row to update yet.
+An UPDATE form would silently match zero rows there and leave the
+database migrated but unstamped — reporting version 0 forever, and
+re-applying migration 1 on every startup.  The DELETE+INSERT shape is
+also what makes the stamp a replace, so the row never duplicates.
+
+Idempotence across restarts: a database already at the latest version
+has no pending migrations, so the runner opens a read-only check, finds
+nothing to do, and leaves the file byte-untouched (no write transaction
+is opened, so no WAL churn).
+
+Migration list policy: entries are append-only.  Once shipped, a
+migration's SQL must never be edited — an old database applying it for
+the first time and a fresh database would then diverge.  Fix-forward
+with a new migration instead.  The version stamp lives in the same
+SQLite file as the data it describes, so restoring a backup restores
+its matching schema version with it.
+
+Corrupt or missing files are not this module's concern: startup
+handling of those cases is task d5bca74b, which decides whether to
+open fresh or raise ConfigEntryNotReady.  This runner assumes it is
+handed an open, working connection.
+"""
+from __future__ import annotations
+
+import asyncio
+import logging
+from collections.abc import Sequence
+
+from .db import NestQuestDatabase
+from .schema import SCHEMA_V1_STATEMENTS
+
+LOGGER = logging.getLogger(__name__)
+
+#: Metadata table holding the applied schema version.  Prefixed with the
+#: integration domain so a config directory shared with other tools can
+#: never collide with a foreign ``schema_version`` table.
+VERSION_TABLE = "nestquest_schema_version"
+
+#: DDL for the version metadata table.  The singleton-row invariant is
+#: enforced by the schema itself: ``id`` is fixed at 1 by CHECK, keyed
+#: PRIMARY KEY, so the table can never hold a second row, and the
+#: stamp write is an UPDATE (no DELETE+INSERT needed).  ``version`` is
+#: a positive integer: version 0 means "no row" and is never stored,
+#: so a negative or zero stored value is corruption, not a state the
+#: runner can act on.
+VERSION_TABLE_DDL = f"""
+    CREATE TABLE IF NOT EXISTS {VERSION_TABLE} (
+        id INTEGER NOT NULL PRIMARY KEY CHECK (id = 1),
+        version INTEGER NOT NULL CHECK (version >= 1)
+    )
+"""
+
+#: One-based index into :data:`MIGRATIONS`: entry ``n`` upgrades
+#: version ``n-1`` to version ``n``.
+MIGRATION_1_V1_DDL: list[str] = list(SCHEMA_V1_STATEMENTS)
+
+#: The ordered migration list.  Append-only: never edit an applied
+#: entry, add the next one instead.
+MIGRATIONS: Sequence[Sequence[str]] = [
+    MIGRATION_1_V1_DDL,
+]
+
+
+async def _create_version_table(database: NestQuestDatabase) -> None:
+    """Create the version metadata table if it does not exist.
+
+    The table is created before any version check: it is the runner's
+    own bookkeeping, and creating it is idempotent.  The DDL enforces
+    the singleton-row invariant (``id`` fixed at 1) and a positive
+    integer version at the database level.
+    """
+    await database.execute(VERSION_TABLE_DDL)
+
+
+async def read_schema_version(database: NestQuestDatabase) -> int:
+    """Return the schema version recorded in the database.
+
+    Returns 0 when the version table or its row is missing — the
+    "fresh file" case.  A stored version higher than the runner knows
+    is surfaced as-is; the caller decides how to treat a future version.
+
+    Reading is deliberately passive: a missing table raises, it is not
+    swallowed into 0, because :func:`apply_migrations` always creates
+    the table before reading and a direct reader hitting "no such
+    table" is a caller bug worth surfacing, not a fresh file.
+    """
+    row = await database.fetch_one(
+        f"SELECT version FROM {VERSION_TABLE} LIMIT 1"
+    )
+    if row is None:
+        return 0
+    version = row[0]
+    if not isinstance(version, int) or isinstance(version, bool):
+        raise RuntimeError(
+            f"Schema version metadata is not an integer: {version!r}"
+        )
+    if version < 1:
+        raise RuntimeError(
+            f"Schema version metadata is invalid (must be >= 1): {version!r}"
+        )
+    return version
+
+
+#: One asyncio.Lock per connection wrapper, created lazily and bound to
+#: the running loop, serializing whole apply_migrations runs so two
+#: concurrent callers on one connection queue instead of colliding on
+#: the wrapper's single-transaction rule.
+_MIGRATION_LOCKS: dict[int, asyncio.Lock] = {}
+
+
+def _migration_lock(database: NestQuestDatabase) -> asyncio.Lock:
+    """Return the migration lock bound to ``database``'s running loop."""
+    loop = asyncio.get_running_loop()
+    key = (id(database), id(loop))
+    lock = _MIGRATION_LOCKS.get(key)
+    if lock is None:
+        lock = asyncio.Lock()
+        _MIGRATION_LOCKS[key] = lock
+    return lock
+
+
+async def apply_migrations(
+    database: NestQuestDatabase,
+    migrations: Sequence[Sequence[str]] = MIGRATIONS,
+) -> int:
+    """Bring the database schema up to the latest version.
+
+    Reads the current version, applies every pending migration in order
+    — each inside one transaction that also stamps the new version —
+    and returns the resulting version.  Applying zero pending
+    migrations (database already current) is a no-op that logs at debug
+    level and opens no write transaction.
+
+    The version is re-read inside each migration transaction before
+    deciding to apply it: the outer read is advisory only (loop bounds,
+    no-op fast path), and on one shared connection two interleaved
+    runners would otherwise both read the same version and both apply
+    a non-idempotent migration.  Under the transaction's lock the
+    second runner sees the first runner's stamp and skips.
+
+    Runners on one connection are serialized by an asyncio lock held
+    for the whole decide-and-apply span: NestQuestDatabase rejects a
+    second transaction while one is active (RuntimeError), so
+    concurrent callers must queue, and the lock makes that queueing
+    explicit.  The loser of the race re-reads the version once it
+    acquires the lock, sees the winner's stamp, and applies nothing.
+
+    Raises whatever the failing migration raised, with the database
+    rolled back to its prior version and prior rows untouched.
+    """
+    async with _migration_lock(database):
+        await _create_version_table(database)
+        current = await read_schema_version(database)
+        latest = len(migrations)
+
+        if current > latest:
+            raise RuntimeError(
+                f"Database schema version {current} is newer than this "
+                f"integration understands (latest known: {latest}); "
+                "downgrades are not supported"
+            )
+
+        if current == latest:
+            LOGGER.debug(
+                "NestQuest schema already at version %d; "
+                "no migrations to apply",
+                current,
+            )
+            return current
+
+        for target in range(current + 1, latest + 1):
+            applied = False
+            async with database.transaction():
+                # Re-read the version INSIDE the write transaction: the
+                # outer read was advisory, and the wrapper serializes
+                # individual statements, not the read-decide-apply
+                # decision.  Under the transaction's lock the version
+                # cannot change between the read and the stamp, and the
+                # loser of an interleaved race (a queued second caller
+                # re-running apply_migrations after the winner already
+                # migrated) re-reads here, sees the winner's stamp, and
+                # skips instead of re-applying a non-idempotent
+                # migration with a stale version.
+                in_tx_version = await read_schema_version(database)
+                if in_tx_version > latest:
+                    raise RuntimeError(
+                        f"Database schema version {in_tx_version} is newer "
+                        f"than this integration understands (latest known: "
+                        f"{latest}); downgrades are not supported"
+                    )
+                if in_tx_version < target:
+                    for sql in migrations[target - 1]:
+                        await database.execute(sql)
+                    # INSERT keyed on the singleton row (id = 1): a
+                    # fresh file has no row yet, and migration 1 is the
+                    # only migration a version-0 database can run, so
+                    # the row is seeded by the same statement batch
+                    # when needed.  UPDATE alone would silently match
+                    # zero rows there.
+                    await database.execute(
+                        f"INSERT INTO {VERSION_TABLE} (id, version) "
+                        "VALUES (1, ?) "
+                        "ON CONFLICT (id) DO UPDATE SET version = "
+                        "excluded.version",
+                        (target,),
+                    )
+                    applied = True
+            if applied:
+                LOGGER.info(
+                    "NestQuest schema migrated to version %d "
+                    "(%d statement%s)",
+                    target,
+                    len(migrations[target - 1]),
+                    "s" if len(migrations[target - 1]) != 1 else "",
+                )
+
+        return latest

custom_components/nestquest/schema.py

@@ -0,0 +1,336 @@
+"""Declarative schema DDL for the NestQuest SQLite database.
+
+Every v1 table is declared here as plain SQL statements so later schema
+tasks can append their own DDL to :data:`SCHEMA_V1_STATEMENTS` without
+touching this module's tables.  All statements use
+``CREATE TABLE IF NOT EXISTS`` so application is idempotent; the versioned
+migration runner is a separate later concern.
+
+Timestamp policy: all timestamps are UTC ISO-8601 strings, set by the
+caller/DAO rather than a DB default, per the feature guardrails.  No
+``length(created_at) = 25`` CHECK is added: the exact string shape
+produced by callers is not fixed yet (``datetime.isoformat()`` may
+include microseconds, changing the length), so enforcing a fixed length
+here would reject valid values.  Only non-null is enforced for now.
+
+Date policy: ``start_date``/``end_date`` are ISO date strings (YYYY-MM-DD,
+no time component) compared lexically by the ``end_date >= start_date``
+CHECK; due_date/due_time string shapes are caller-validated by the rule
+engine and DAO layers, not by DDL.
+
+``weekday_set`` format: comma-separated weekday integers (CSV), 0 =
+Monday .. 6 = Sunday, e.g. ``'0,2,4'`` for Mon/Wed/Fri.  Chosen over JSON
+because it sorts, compares and parses trivially in SQL.  The format is
+enforced at the DB level: a CHECK matches ``weekday_set`` against GLOB
+patterns for element counts 1..7 of single digits 0-6 (GLOB has no
+repetition quantifier, so the element count is enumerated; more than 7
+elements is impossible for a weekday set).  ``''``, ``'x'``, ``'7'`` and
+``'0,x'`` are all rejected; NULL stays allowed for non-weekly rules.
+This keeps the schema layer storage-only — the DAO layer (tasks
+8c72300c+) does not need its own validator, it can rely on the CHECK.
+
+Type affinity: SQLite applies column affinity on insert, but CHECKs
+still observe text and fractional values ('abc' stays text, '1.5'
+becomes REAL), so every INTEGER column carrying rule semantics carries
+a ``typeof(...) = 'integer'`` guard in its CHECK.
+
+Rule-type coherence: two CHECKs enforce that ``weekly`` carries a
+non-null ``weekday_set``, ``monthly`` carries a ``day_of_month`` or an
+``nth_weekday``, ``yearly`` carries a ``month``, and ``daily``/``custom``
+carry none of the month-specific fields.  Relaxed deliberately: the DDL
+does NOT forbid ``month`` on weekly/monthly rules (an "every 2 weeks"
+rule or a monthly rule could later be pinned to a month) nor extra
+fields on weekly/monthly/yearly rules generally, so the CHECKs only
+reject what the rule engine definitively cannot express now.
+
+Presence pattern format: ``presence_schedules.pattern`` encodes the
+whole N-week repeating cycle in one TEXT column as pipe-separated
+segments, one per week of the cycle: segment ``i`` is a ``weekday_set``
+CSV (same single-digit 0-6 convention as ``schedule_rules.weekday_set``)
+for week ``i``, e.g. ``'0,2,4|1,3'`` = Mon/Wed/Fri in week 0, Tue/Thu in
+week 1.  An empty segment means the child is absent every day of that
+week; a wholly empty pattern with ``cycle_length_weeks = 1`` means
+absent every day of every week, which is distinct from having no
+schedule row at all (a child with no schedule is present every day, per
+the feature guardrails).  Chosen over JSON or per-week rows to stay
+consistent with the CSV ``weekday_set`` convention and fully checkable
+by plain CHECKs.  DB-level validation is pure CHECK, no triggers or
+custom functions: char-class GLOBs reject every character outside
+digits 0-6, comma and pipe; adjacency GLOBs reject empty elements
+(double comma, comma next to a pipe, leading/trailing comma) and
+two-digit runs; a further GLOB rejects contiguous runs of 8+ comma
+separated digits, which caps a segment at 7 elements — the GLOB cannot
+match across a ``|``, so cross-segment boundaries stay safe; and the
+segment count is pinned to ``cycle_length_weeks`` by
+``LENGTH(pattern) - LENGTH(REPLACE(pattern, '|', '')) + 1``.  Per
+weekday_set this is not full CSV-set normalisation (duplicates like
+``'0,0'`` or unsorted sets stay storable, as with ``schedule_rules``);
+the engine treats the segment as a set.  A
+one-row-per-``week_index`` normalization was considered and rejected:
+the flat single-column encoding keeps the done-condition's table shape
+and proved fully checkable with plain CHECKs.
+
+``cycle_length_weeks`` is capped at 4: 2 (alternating weeks) is the
+common case, and a small cap keeps anchor arithmetic and the encoded
+pattern human-readable.  Revisit the cap — and re-run the pattern
+validation matrix in tests — if a longer cycle is ever needed.
+``anchor_date`` is an ISO date string pinning the cycle: the week index
+of a date is (days since anchor) // 7 mod ``cycle_length_weeks``,
+computed by the presence engine (Feature 05) from anchor-date
+arithmetic, never ISO week parity.  Like other date columns it carries
+no shape CHECK, matching the established date policy.
+
+Presence overrides: ``presence_overrides.end_date`` is NOT NULL,
+unlike ``schedule_rules.end_date`` — an override is always a concrete
+date range; a single-day override stores the same date in both columns.
+``is_present`` 0/1 marks the child absent/present for the whole range;
+``note`` is optional free text.
+
+Task instances: ``task_instances`` deliberately carries NO completion
+status column.  An instance's current state derives from the latest row
+in ``completion_events`` (Feature 08), so materialization (Feature 07)
+can insert instances without knowing anything about completion and the
+append-only log stays the single source of truth.  ``definition_id``,
+``due_date`` and ``child_id`` snapshot the materialization-time facts
+("why this instance exists"): reassignment and rule edits change future
+instances only and never rewrite these rows.  ``due_time`` snapshots
+the definition's optional due time at generation for the same reason —
+the instance keeps its generation-time value even if the definition is
+edited later.  ``generated_at`` is a caller-set UTC ISO-8601 timestamp
+per the module timestamp policy (no DB default, so a generation batch
+stamps one coherent time).
+
+Uniqueness: the (definition_id, due_date) pair is declared as a
+table-level ``UNIQUE`` constraint rather than a separate ``CREATE
+UNIQUE INDEX`` statement.  SQLite materializes it as an implicit unique
+index (``sqlite_autoindex_task_instances_1``) — the required "unique
+index prevents duplicate instances" — and the constraint form cannot be
+silently dropped the way a standalone index can, so the duplicate door
+stays shut.  Idempotent materialization keys on exactly this pair.  No
+secondary indexes beyond it are declared yet: history and board queries
+(Features 08/10/13) should justify their indexes as a later migration
+once their query shapes exist.
+
+No ``ON DELETE`` clauses are declared on any foreign key in this
+module: children and definitions are deactivated, never deleted, so a
+deletion that would orphan instances or events is a bug and must fail
+loudly rather than cascade.
+
+Completion events: ``completion_events`` is strictly append-only.  That
+property is enforced at the DAO layer — the completion-events DAO
+exposes no UPDATE or DELETE path (task a9ea75fc) — and deliberately NOT
+by database triggers, matching the module's no-trigger policy: a RAISE
+trigger would be the one exception to "pure CHECK, no triggers",
+complicate the later migration runner, and still prove nothing (any
+writer can run raw SQL).  ``event_type`` is constrained to
+``completed``/``uncompleted``; a ``missed`` row is intentionally not
+representable — missed is a derived state announced on the HA event bus
+(Feature 10), never an appended event.
+
+``child_id`` is deliberately denormalized (it is also derivable via
+``task_instances``): history reporting (Feature 13) filters and rates
+per child directly against the log, and the log should stay
+self-describing without joins.
+
+Actor policy: ``actor_source`` distinguishes an authenticated HA user
+(``'user'``, with ``actor_user_id`` holding the HA user id) from a
+panel tap with no user context (``'panel'``, with ``actor_user_id``
+NULL — the tapped child profile is already ``child_id``).  A coherence
+CHECK makes the pair shape non-negotiable: ``'user'`` requires
+``actor_user_id``, ``'panel'`` forbids it.  Other actor sources are
+rejected; if an unattended system actor is ever needed, that is a
+schema migration, not a silent widening.
+
+On-time policy: ``was_on_time`` is required (integer 0 or 1) for
+``completed`` events — at completion time the due date is known and the
+flag is decidable.  For ``uncompleted`` events the flag is optional:
+Feature 08 decides whether a reversal carries the reversed completion's
+on-time flag or NULL, and the DDL deliberately accepts both rather than
+guessing.
+"""
+from __future__ import annotations
+
+from .db import NestQuestDatabase
+
+#: GLOB patterns matching a valid ``weekday_set`` CSV: one GLOB per
+#: possible element count 1..7 (a weekday set cannot exceed 7 elements).
+#: Each element is a single digit 0-6, separated by a literal comma.
+#: GLOB has no repetition quantifier, so the element count is enumerated.
+#: ``''`` and NULL are deliberately NOT matched: NULL is allowed for
+#: non-weekly rules via a separate ``IS NULL`` arm, and '' is invalid
+#: because weekly rules need at least one weekday.
+WEEKDAY_SET_GLOB_PATTERNS: list[str] = [
+    "[0-6]",
+    "[0-6],[0-6]",
+    "[0-6],[0-6],[0-6]",
+    "[0-6],[0-6],[0-6],[0-6]",
+    "[0-6],[0-6],[0-6],[0-6],[0-6]",
+    "[0-6],[0-6],[0-6],[0-6],[0-6],[0-6]",
+    "[0-6],[0-6],[0-6],[0-6],[0-6],[0-6],[0-6]",
+]
+
+SCHEMA_V1_CHILDREN_DDL: list[str] = [
+    """
+    CREATE TABLE IF NOT EXISTS children (
+        id INTEGER PRIMARY KEY AUTOINCREMENT,
+        display_name TEXT NOT NULL,
+        colour TEXT,
+        avatar_ref TEXT,
+        sort_order INTEGER NOT NULL DEFAULT 0 CHECK (typeof(sort_order) = 'integer'),
+        is_active INTEGER NOT NULL DEFAULT 1 CHECK (typeof(is_active) = 'integer' AND is_active IN (0, 1)),
+        created_at TEXT NOT NULL
+    )
+    """,
+]
+
+SCHEMA_V1_ADMIN_USERS_DDL: list[str] = [
+    """
+    CREATE TABLE IF NOT EXISTS admin_users (
+        ha_user_id TEXT PRIMARY KEY NOT NULL,
+        added_at TEXT NOT NULL
+    )
+    """,
+]
+
+_WEEKDAY_SET_CHECK = " OR ".join(
+    f"weekday_set GLOB '{pattern}'" for pattern in WEEKDAY_SET_GLOB_PATTERNS
+)
+
+SCHEMA_V1_SCHEDULE_RULES_DDL: list[str] = [
+    f"""
+    CREATE TABLE IF NOT EXISTS schedule_rules (
+        id INTEGER PRIMARY KEY AUTOINCREMENT,
+        rule_type TEXT NOT NULL CHECK (rule_type IN ('daily', 'weekly', 'monthly', 'yearly', 'custom')),
+        interval INTEGER NOT NULL DEFAULT 1 CHECK (typeof(interval) = 'integer' AND interval >= 1),
+        weekday_set TEXT CHECK (weekday_set IS NULL OR ({_WEEKDAY_SET_CHECK})),
+        day_of_month INTEGER CHECK (day_of_month IS NULL OR (typeof(day_of_month) = 'integer' AND day_of_month >= 1 AND day_of_month <= 31)),
+        nth_weekday INTEGER CHECK (nth_weekday IS NULL OR (typeof(nth_weekday) = 'integer' AND nth_weekday IN (-1, 1, 2, 3, 4, 5))),
+        month INTEGER CHECK (month IS NULL OR (typeof(month) = 'integer' AND month >= 1 AND month <= 12)),
+        start_date TEXT NOT NULL,
+        end_date TEXT,
+        CHECK (end_date IS NULL OR end_date >= start_date),
+        CHECK (
+            (rule_type = 'weekly' AND weekday_set IS NOT NULL)
+            OR (rule_type = 'monthly' AND (day_of_month IS NOT NULL OR nth_weekday IS NOT NULL))
+            OR (rule_type = 'yearly' AND month IS NOT NULL)
+            OR (rule_type IN ('daily', 'custom') AND day_of_month IS NULL AND nth_weekday IS NULL AND month IS NULL)
+        )
+    )
+    """,
+]
+
+SCHEMA_V1_TASK_DEFINITIONS_DDL: list[str] = [
+    """
+    CREATE TABLE IF NOT EXISTS task_definitions (
+        id INTEGER PRIMARY KEY AUTOINCREMENT,
+        title TEXT NOT NULL,
+        description TEXT,
+        icon TEXT,
+        child_id INTEGER NOT NULL REFERENCES children(id),
+        schedule_rule_id INTEGER NOT NULL REFERENCES schedule_rules(id),
+        due_time TEXT,
+        is_active INTEGER NOT NULL DEFAULT 1 CHECK (typeof(is_active) = 'integer' AND is_active IN (0, 1)),
+        created_at TEXT NOT NULL
+    )
+    """,
+]
+
+SCHEMA_V1_PRESENCE_SCHEDULES_DDL: list[str] = [
+    f"""
+    CREATE TABLE IF NOT EXISTS presence_schedules (
+        id INTEGER PRIMARY KEY AUTOINCREMENT,
+        child_id INTEGER NOT NULL UNIQUE REFERENCES children(id),
+        cycle_length_weeks INTEGER NOT NULL CHECK (typeof(cycle_length_weeks) = 'integer' AND cycle_length_weeks >= 1 AND cycle_length_weeks <= 4),
+        anchor_date TEXT NOT NULL,
+        pattern TEXT NOT NULL CHECK (
+            NOT pattern GLOB '*[^0-6,|]*'
+            AND NOT pattern GLOB '*[0-6][0-6]*'
+            AND NOT pattern GLOB '*,,*'
+            AND NOT pattern GLOB '*,|*'
+            AND NOT pattern GLOB '*|,*'
+            AND NOT pattern GLOB ',*'
+            AND NOT pattern GLOB '*,'
+            AND NOT pattern GLOB '*[0-6],[0-6],[0-6],[0-6],[0-6],[0-6],[0-6],[0-6]*'
+            AND (LENGTH(pattern) - LENGTH(REPLACE(pattern, '|', '')) + 1) = cycle_length_weeks
+        )
+    )
+    """,
+]
+
+SCHEMA_V1_PRESENCE_OVERRIDES_DDL: list[str] = [
+    """
+    CREATE TABLE IF NOT EXISTS presence_overrides (
+        id INTEGER PRIMARY KEY AUTOINCREMENT,
+        child_id INTEGER NOT NULL REFERENCES children(id),
+        start_date TEXT NOT NULL,
+        end_date TEXT NOT NULL,
+        is_present INTEGER NOT NULL CHECK (typeof(is_present) = 'integer' AND is_present IN (0, 1)),
+        note TEXT,
+        CHECK (end_date >= start_date)
+    )
+    """,
+]
+
+SCHEMA_V1_TASK_INSTANCES_DDL: list[str] = [
+    """
+    CREATE TABLE IF NOT EXISTS task_instances (
+        id INTEGER PRIMARY KEY AUTOINCREMENT,
+        definition_id INTEGER NOT NULL REFERENCES task_definitions(id),
+        child_id INTEGER NOT NULL REFERENCES children(id),
+        due_date TEXT NOT NULL,
+        due_time TEXT,
+        generated_at TEXT NOT NULL,
+        UNIQUE (definition_id, due_date)
+    )
+    """,
+]
+
+SCHEMA_V1_COMPLETION_EVENTS_DDL: list[str] = [
+    """
+    CREATE TABLE IF NOT EXISTS completion_events (
+        id INTEGER PRIMARY KEY AUTOINCREMENT,
+        instance_id INTEGER NOT NULL REFERENCES task_instances(id),
+        child_id INTEGER NOT NULL REFERENCES children(id),
+        event_type TEXT NOT NULL CHECK (event_type IN ('completed', 'uncompleted')),
+        actor_source TEXT NOT NULL CHECK (actor_source IN ('user', 'panel')),
+        actor_user_id TEXT,
+        occurred_at TEXT NOT NULL,
+        was_on_time INTEGER CHECK (
+            was_on_time IS NULL
+            OR (typeof(was_on_time) = 'integer' AND was_on_time IN (0, 1))
+        ),
+        CHECK (
+            (actor_source = 'user' AND actor_user_id IS NOT NULL)
+            OR (actor_source = 'panel' AND actor_user_id IS NULL)
+        ),
+        CHECK (
+            (event_type = 'completed' AND was_on_time IS NOT NULL)
+            OR (event_type = 'uncompleted')
+        )
+    )
+    """,
+]
+
+SCHEMA_V1_STATEMENTS: list[str] = [
+    *SCHEMA_V1_CHILDREN_DDL,
+    *SCHEMA_V1_ADMIN_USERS_DDL,
+    *SCHEMA_V1_SCHEDULE_RULES_DDL,
+    *SCHEMA_V1_TASK_DEFINITIONS_DDL,
+    *SCHEMA_V1_PRESENCE_SCHEDULES_DDL,
+    *SCHEMA_V1_PRESENCE_OVERRIDES_DDL,
+    *SCHEMA_V1_TASK_INSTANCES_DDL,
+    *SCHEMA_V1_COMPLETION_EVENTS_DDL,
+]
+
+
+async def async_apply_ddl(
+    database: NestQuestDatabase, statements: list[str]
+) -> None:
+    """Apply each DDL statement inside one transaction on ``database``.
+
+    Idempotent: every statement is ``CREATE TABLE IF NOT EXISTS``, so
+    applying the same list twice leaves the schema and its rows intact.
+    """
+    async with database.transaction():
+        for sql in statements:
+            await database.execute(sql)

tests/conftest.py

@@ -25,6 +25,9 @@ import asyncio
 import importlib.util
 import inspect
 import sys
+import tempfile
+import weakref
+from pathlib import Path
 from types import SimpleNamespace
 from unittest.mock import MagicMock
 
@@ -218,13 +221,35 @@ def wire_entry_to_registry(entry, registry: ListenerRegistry):
     return entry
 
 
+class _HassNamespace(SimpleNamespace):
+    """SimpleNamespace subclass so the hass stub can hold weak references."""
+
+
 def make_hass() -> tuple:
     """Create a hass stub plus its listener registry, mirroring HA's shape."""
-    hass = SimpleNamespace(
+    config_dir = Path(tempfile.mkdtemp(prefix="nestquest-hass-"))
+    hass = _HassNamespace(
         data={},
         config=MagicMock(),
         config_entries=SimpleNamespace(async_reload=None),
     )
+
+    def _cleanup_config_dir():
+        import shutil
+
+        shutil.rmtree(config_dir, ignore_errors=True)
+
+    weakref.finalize(hass, _cleanup_config_dir)
+    hass.config.path = MagicMock(
+        side_effect=lambda name: str(config_dir / (name or "config"))
+    )
+
+    def _run_executor_job(fn, *args, **kwargs):
+        return asyncio.get_running_loop().run_in_executor(
+            None, lambda: fn(*args, **kwargs)
+        )
+
+    hass.async_add_executor_job = _run_executor_job
     registry = ListenerRegistry(hass)
 
     async def _async_reload(entry_id: str) -> None:

tests/test_dao_children.py

@@ -0,0 +1,553 @@
+"""Tests for dao_children.py: typed DAO for children and admin_users."""
+from __future__ import annotations
+
+import asyncio
+import sqlite3
+
+import pytest
+
+from custom_components.nestquest.dao_children import (
+    AdminUserRecord,
+    AdminUsersDao,
+    ChildRecord,
+    ChildrenDao,
+)
+from custom_components.nestquest.db import NestQuestDatabase
+from custom_components.nestquest.schema import SCHEMA_V1_STATEMENTS
+from custom_components.nestquest.migrations import apply_migrations
+
+
+def _run(coro):
+    return asyncio.new_event_loop().run_until_complete(coro)
+
+
+def _make_hass_mock():
+    from unittest.mock import AsyncMock, MagicMock
+
+    hass = MagicMock()
+    hass.async_add_executor_job = AsyncMock(side_effect=(lambda fn, *a: fn(*a)))
+    return hass
+
+
+def _open_db(path) -> NestQuestDatabase:
+    database = NestQuestDatabase(_make_hass_mock())
+    _run(database.open(path))
+    _run(apply_migrations(database))
+    return database
+
+
+def _daos(database) -> tuple[ChildrenDao, AdminUsersDao]:
+    return ChildrenDao(database), AdminUsersDao(database)
+
+
+NOW = "2026-09-14T11:00:00+00:00"
+
+
+def _make_child(dao, name="Ada", **kwargs) -> ChildRecord:
+    return _run(dao.create(name, NOW, **kwargs))
+
+
+# ---------------------------------------------------------------------------
+# children: create and get
+# ---------------------------------------------------------------------------
+
+
+def test_create_returns_typed_record(tmp_path) -> None:
+    database = _open_db(tmp_path / "create.db")
+    try:
+        dao, _ = _daos(database)
+        child = _make_child(dao, colour="#ff0000", avatar_ref="avatars/1")
+        assert isinstance(child, ChildRecord)
+        assert child.id == 1
+        assert child.display_name == "Ada"
+        assert child.colour == "#ff0000"
+        assert child.avatar_ref == "avatars/1"
+        assert child.sort_order == 0
+        assert child.is_active is True
+        assert child.created_at == NOW
+    finally:
+        _run(database.close())
+
+
+def test_get_returns_none_for_missing_child(tmp_path) -> None:
+    database = _open_db(tmp_path / "get-missing.db")
+    try:
+        dao, _ = _daos(database)
+        assert _run(dao.get(999)) is None
+    finally:
+        _run(database.close())
+
+
+def test_create_duplicate_name_is_allowed(tmp_path) -> None:
+    database = _open_db(tmp_path / "dup-name.db")
+    try:
+        dao, _ = _daos(database)
+        first = _make_child(dao, "Ada")
+        second = _make_child(dao, "Ada")
+        assert first.id != second.id
+    finally:
+        _run(database.close())
+
+
+# ---------------------------------------------------------------------------
+# children: list active / list all
+# ---------------------------------------------------------------------------
+
+
+def test_list_active_excludes_inactive_and_sorts(tmp_path) -> None:
+    database = _open_db(tmp_path / "list-active.db")
+    try:
+        dao, _ = _daos(database)
+        _make_child(dao, "Bo", sort_order=2)
+        ada = _make_child(dao, "Ada", sort_order=1)
+        cy = _make_child(dao, "Cy", sort_order=1)
+        _make_child(dao, "Dee", sort_order=0)
+        _run(dao.set_active(ada.id, False))
+        active = _run(dao.list_active())
+        assert [c.display_name for c in active] == ["Dee", "Cy", "Bo"]
+        assert all(c.is_active for c in active)
+    finally:
+        _run(database.close())
+
+
+def test_list_all_includes_inactive(tmp_path) -> None:
+    database = _open_db(tmp_path / "list-all.db")
+    try:
+        dao, _ = _daos(database)
+        ada = _make_child(dao, "Ada", sort_order=1)
+        _make_child(dao, "Bo", sort_order=0)
+        _run(dao.set_active(ada.id, False))
+        all_children = _run(dao.list_all())
+        assert [c.display_name for c in all_children] == ["Bo", "Ada"]
+        assert all_children[1].is_active is False
+    finally:
+        _run(database.close())
+
+
+# ---------------------------------------------------------------------------
+# children: update, set_active, reorder
+# ---------------------------------------------------------------------------
+
+
+def test_update_fields_round_trip(tmp_path) -> None:
+    database = _open_db(tmp_path / "update.db")
+    try:
+        dao, _ = _daos(database)
+        child = _make_child(dao, "Ada", colour="#111111")
+        updated = _run(
+            dao.update(
+                child.id,
+                display_name="Ada L.",
+                colour="#222222",
+                avatar_ref="avatars/x.png",
+            )
+        )
+        assert updated == 1
+        fetched = _run(dao.get(child.id))
+        assert fetched is not None
+        assert fetched.display_name == "Ada L."
+        assert fetched.colour == "#222222"
+        assert fetched.avatar_ref == "avatars/x.png"
+        assert fetched.sort_order == 0
+    finally:
+        _run(database.close())
+
+
+def test_update_omitted_fields_untouched(tmp_path) -> None:
+    database = _open_db(tmp_path / "update-partial.db")
+    try:
+        dao, _ = _daos(database)
+        child = _make_child(dao, "Ada", colour="#111111")
+        _run(dao.update(child.id, display_name="Ada L."))
+        fetched = _run(dao.get(child.id))
+        assert fetched.colour == "#111111"
+    finally:
+        _run(database.close())
+
+
+def test_update_no_fields_returns_zero_and_changes_nothing(tmp_path) -> None:
+    database = _open_db(tmp_path / "update-empty.db")
+    try:
+        dao, _ = _daos(database)
+        child = _make_child(dao, "Ada")
+        assert _run(dao.update(child.id)) == 0
+        fetched = _run(dao.get(child.id))
+        assert fetched is not None and fetched.display_name == "Ada"
+    finally:
+        _run(database.close())
+
+
+def test_update_missing_child_returns_zero(tmp_path) -> None:
+    database = _open_db(tmp_path / "update-missing.db")
+    try:
+        dao, _ = _daos(database)
+        assert _run(dao.update(999, display_name="X")) == 0
+    finally:
+        _run(database.close())
+
+
+def test_set_active_missing_child_returns_zero(tmp_path) -> None:
+    database = _open_db(tmp_path / "set-active-missing.db")
+    try:
+        dao, _ = _daos(database)
+        assert _run(dao.set_active(999, False)) == 0
+    finally:
+        _run(database.close())
+
+
+def test_reorder_assigns_positions_in_order(tmp_path) -> None:
+    database = _open_db(tmp_path / "reorder.db")
+    try:
+        dao, _ = _daos(database)
+        a = _make_child(dao, "Ada")
+        b = _make_child(dao, "Bo")
+        c = _make_child(dao, "Cy")
+        _run(dao.reorder([c.id, a.id, b.id]))
+        children = _run(dao.list_all())
+        assert [x.display_name for x in children] == ["Cy", "Ada", "Bo"]
+        assert [x.sort_order for x in children] == [0, 1, 2]
+    finally:
+        _run(database.close())
+
+
+def test_reorder_is_transactional_and_idempotent(tmp_path) -> None:
+    database = _open_db(tmp_path / "reorder-idempotent.db")
+    try:
+        dao, _ = _daos(database)
+        a = _make_child(dao, "Ada")
+        b = _make_child(dao, "Bo")
+        _run(dao.reorder([b.id, a.id]))
+        _run(dao.reorder([b.id, a.id]))
+        children = _run(dao.list_all())
+        assert [(x.display_name, x.sort_order) for x in children] == [
+            ("Bo", 0),
+            ("Ada", 1),
+        ]
+    finally:
+        _run(database.close())
+
+
+def test_reorder_empty_list_is_noop(tmp_path) -> None:
+    database = _open_db(tmp_path / "reorder-empty.db")
+    try:
+        dao, _ = _daos(database)
+        _make_child(dao, "Ada")
+        _run(dao.reorder([]))
+        children = _run(dao.list_all())
+        assert children[0].sort_order == 0
+    finally:
+        _run(database.close())
+
+
+def test_reorder_unknown_id_leaves_it_untouched(tmp_path) -> None:
+    database = _open_db(tmp_path / "reorder-unknown.db")
+    try:
+        dao, _ = _daos(database)
+        a = _make_child(dao, "Ada")
+        _run(dao.reorder([a.id, 999]))
+        children = _run(dao.list_all())
+        assert children[0].sort_order == 0
+    finally:
+        _run(database.close())
+
+
+def test_reorder_rolls_back_to_original_order_on_failure(tmp_path) -> None:
+    """A failing finalize batch rolls the whole reorder back.
+
+    The two-phase staging is only meaningful if a crash between the
+    batches leaves the original order intact: monkeypatch execute_many
+    so the finalize (non-negative) batch raises, then assert every
+    sort_order is unchanged.
+    """
+    database = _open_db(tmp_path / "reorder-rollback.db")
+    try:
+        dao, _ = _daos(database)
+        a = _make_child(dao, "Ada", sort_order=0)
+        b = _make_child(dao, "Bo", sort_order=1)
+
+        original_execute_many = database.execute_many
+
+        async def _failing_execute_many(sql, parameters):
+            # The staging batch writes negative positions; the finalize
+            # batch writes 0..n-1.  Fail the finalize batch.
+            if all(position >= 0 for position, _ in parameters):
+                raise sqlite3.OperationalError("boom")
+            return await original_execute_many(sql, parameters)
+
+        database.execute_many = _failing_execute_many
+        with pytest.raises(sqlite3.OperationalError, match="boom"):
+            _run(dao.reorder([b.id, a.id]))
+        children = _run(dao.list_all())
+        assert [(c.display_name, c.sort_order) for c in children] == [
+            ("Ada", 0),
+            ("Bo", 1),
+        ], "failed reorder must leave original sort orders intact"
+    finally:
+        _run(database.close())
+
+
+def test_reorder_rejects_duplicate_ids(tmp_path) -> None:
+    database = _open_db(tmp_path / "reorder-duplicate.db")
+    try:
+        dao, _ = _daos(database)
+        a = _make_child(dao, "Ada")
+        with pytest.raises(ValueError, match="duplicate"):
+            _run(dao.reorder([a.id, a.id]))
+        fetched = _run(dao.get(a.id))
+        assert fetched is not None and fetched.sort_order == 0
+    finally:
+        _run(database.close())
+
+
+def test_reorder_concurrent_calls_serialize(tmp_path) -> None:
+    """Concurrent reorders from DIFFERENT DAO instances queue safely.
+
+    Two ChildrenDao objects over one connection race two reorders: the
+    connection-scoped lock makes the second wait, then run against the
+    first call's final state.  Without the lock the wrapper's
+    transaction() would reject the second concurrent transaction with
+    RuntimeError.
+    """
+    async def _main() -> None:
+        database = NestQuestDatabase(_make_hass_mock())
+        await database.open(tmp_path / "reorder-concurrent.db")
+        try:
+            await apply_migrations(database)
+            dao_a, _ = _daos(database)
+            a = await dao_a.create("Ada", NOW)
+            b = await dao_a.create("Bo", NOW)
+            dao_b, _ = _daos(database)  # second instance, same connection
+            task_1 = asyncio.ensure_future(dao_a.reorder([b.id, a.id]))
+            await asyncio.sleep(0)
+            task_2 = asyncio.ensure_future(dao_b.reorder([a.id, b.id]))
+            await asyncio.gather(task_1, task_2)
+            children = await dao_a.list_all()
+            orders = {c.display_name: c.sort_order for c in children}
+            assert sorted(orders.values()) == [0, 1]
+        finally:
+            await database.close()
+
+    _run(_main())
+
+
+# ---------------------------------------------------------------------------
+# admin_users: add, remove, list, exists
+# ---------------------------------------------------------------------------
+
+
+def test_admin_add_then_exists(tmp_path) -> None:
+    database = _open_db(tmp_path / "admin-add.db")
+    try:
+        _, dao = _daos(database)
+        assert _run(dao.add("user-1", NOW)) is True
+        assert _run(dao.exists("user-1")) is True
+        assert _run(dao.exists("user-2")) is False
+    finally:
+        _run(database.close())
+
+
+def test_admin_add_is_idempotent(tmp_path) -> None:
+    database = _open_db(tmp_path / "admin-idempotent.db")
+    try:
+        _, dao = _daos(database)
+        assert _run(dao.add("user-1", NOW)) is True
+        assert _run(dao.add("user-1", NOW)) is False
+        records = _run(dao.list())
+        assert len(records) == 1
+        assert records[0].added_at == NOW
+    finally:
+        _run(database.close())
+
+
+def test_admin_add_concurrent_calls_are_idempotent(tmp_path) -> None:
+    """Concurrent add() calls of the same user: one inserts, rest False.
+
+    The single-statement ON CONFLICT DO NOTHING makes the decision and
+    the write atomic per statement, so racing coroutines cannot both
+    'see no row' and one of them raise IntegrityError.
+    """
+    async def _main() -> None:
+        database = NestQuestDatabase(_make_hass_mock())
+        await database.open(tmp_path / "admin-race.db")
+        try:
+            await apply_migrations(database)
+            _, dao = _daos(database)
+            tasks = [
+                asyncio.ensure_future(dao.add("user-1", NOW))
+                for _ in range(5)
+            ]
+            await asyncio.sleep(0)
+            results = list(await asyncio.gather(*tasks))
+            assert sorted(results) == [False, False, False, False, True]
+            records = await dao.list()
+            assert len(records) == 1
+            assert records[0].added_at == NOW
+        finally:
+            await database.close()
+
+    _run(_main())
+
+
+def test_admin_add_preserves_original_added_at(tmp_path) -> None:
+    database = _open_db(tmp_path / "admin-added-at.db")
+    try:
+        _, dao = _daos(database)
+        _run(dao.add("user-1", NOW))
+        _run(dao.add("user-1", "2026-09-15T00:00:00+00:00"))
+        records = _run(dao.list())
+        assert records[0].added_at == NOW
+    finally:
+        _run(database.close())
+
+
+def test_admin_remove_returns_true_then_false(tmp_path) -> None:
+    database = _open_db(tmp_path / "admin-remove.db")
+    try:
+        _, dao = _daos(database)
+        _run(dao.add("user-1", NOW))
+        assert _run(dao.remove("user-1")) is True
+        assert _run(dao.remove("user-1")) is False
+        assert _run(dao.exists("user-1")) is False
+    finally:
+        _run(database.close())
+
+
+def test_admin_list_returns_typed_records_ordered(tmp_path) -> None:
+    database = _open_db(tmp_path / "admin-list.db")
+    try:
+        _, dao = _daos(database)
+        _run(dao.add("user-2", "2026-09-14T10:00:00+00:00"))
+        _run(dao.add("user-1", "2026-09-14T09:00:00+00:00"))
+        records = _run(dao.list())
+        assert isinstance(records[0], AdminUserRecord)
+        assert [r.ha_user_id for r in records] == ["user-1", "user-2"]
+        assert records[0].added_at == "2026-09-14T09:00:00+00:00"
+    finally:
+        _run(database.close())
+
+
+def test_admin_exists_empty_allowlist_fails_closed(tmp_path) -> None:
+    database = _open_db(tmp_path / "admin-empty.db")
+    try:
+        _, dao = _daos(database)
+        assert _run(dao.exists("user-1")) is False
+        assert _run(dao.list()) == []
+    finally:
+        _run(database.close())
+
+
+def test_admin_records_are_typed_not_raw_rows(tmp_path) -> None:
+    database = _open_db(tmp_path / "admin-typed.db")
+    try:
+        _, dao = _daos(database)
+        _run(dao.add("user-1", NOW))
+        records = _run(dao.list())
+        assert records == [AdminUserRecord("user-1", NOW)]
+    finally:
+        _run(database.close())
+
+
+# ---------------------------------------------------------------------------
+# No SQL for these tables outside the DAO module
+# ---------------------------------------------------------------------------
+
+
+def test_children_and_admin_sql_lives_only_in_dao_module() -> None:
+    """Guardrail: children/admin_users SQL may appear only in the DAO
+    (and the schema DDL declarations).  Scans the integration package
+    AND the repo's test files RECURSIVELY, matching FROM/INTO/UPDATE/
+    DELETE FROM/JOIN against either table — including DELETE FROM
+    children, the hard-delete path the guardrail forbids.
+
+    Exclusions are exact repo-relative paths, narrowly justified:
+    schema.py declares the tables' DDL; migrations.py applies that DDL;
+    test_schema.py and test_migrations.py test exactly those
+    DDL/migration layers.  None of them touch the tables' data paths —
+    that is the DAO's job.
+    """
+    import re
+    from pathlib import Path
+
+    package = Path(
+        __import__(
+            "custom_components.nestquest", fromlist=["__file__"]
+        ).__file__
+    ).parent
+    repo_root = package.parent.parent
+    scan_roots = [package, repo_root / "tests"]
+
+    allowed = {
+        "custom_components/nestquest/dao_children.py",  # the DAO itself
+        "custom_components/nestquest/schema.py",  # declares the DDL
+        "custom_components/nestquest/migrations.py",  # applies the DDL
+        "tests/test_schema.py",  # tests the DDL
+        "tests/test_migrations.py",  # tests migration application
+        "tests/test_dao_children.py",  # this file, scanned separately
+    }
+    sql_pattern = re.compile(
+        r"(FROM|INTO|UPDATE|DELETE\s+FROM|JOIN)\s+"
+        r'["\`]*(children|admin_users)["\`]*\b',
+        re.IGNORECASE,
+    )
+    offenders: list[str] = []
+    for root in scan_roots:
+        for py in sorted(root.rglob("*.py")):
+            relative = py.relative_to(repo_root).as_posix()
+            if relative in allowed:
+                continue
+            if sql_pattern.search(py.read_text()):
+                offenders.append(relative)
+    assert offenders == [], (
+        f"SQL touching children/admin_users leaked into: {offenders}"
+    )
+
+
+def test_dao_test_file_uses_dao_not_raw_table_sql() -> None:
+    """This test module must exercise the DAO, not raw SQL, for these
+    tables.  The two guard functions in this file necessarily mention
+    the table names inside their regex patterns; their source spans are
+    removed BEFORE the scan, and the remaining lines are then scanned
+    as ONE combined blob (not line-by-line), so SQL split across
+    physical lines — e.g. an implicitly concatenated string ending in
+    FROM children — is still caught.  The guard regexes themselves
+    cannot match the SQL keyword pattern, so removing the spans only
+    spares regex text, not executable SQL.
+    """
+    import ast
+    import re
+    from pathlib import Path
+
+    path = Path(__file__)
+    text = path.read_text()
+    lines = text.splitlines(keepends=True)
+    tree = ast.parse(text)
+    guard_names = {
+        "test_children_and_admin_sql_lives_only_in_dao_module",
+        "test_dao_test_file_uses_dao_not_raw_table_sql",
+    }
+    excluded: set[int] = set()
+    for node in ast.walk(tree):
+        if (
+            isinstance(node, (ast.FunctionDef, ast.AsyncFunctionDef))
+            and node.name in guard_names
+        ):
+            excluded.update(
+                range(node.lineno, (node.end_lineno or node.lineno) + 1)
+            )
+
+    # Scan the source minus excluded lines as ONE blob so SQL split
+    # across physical lines cannot evade the pattern.
+    remaining = "".join(
+        line
+        for number, line in enumerate(lines, start=1)
+        if number not in excluded
+    )
+    sql_pattern = re.compile(
+        r"(SELECT\s[^\"']*?FROM|INSERT\s+INTO|UPDATE|"
+        r"DELETE\s+FROM|FROM|JOIN)\s+[`'\"]*(\[)?"
+        r"(children|admin_users)\b",
+        re.IGNORECASE,
+    )
+    assert sql_pattern.search(remaining) is None, (
+        "tests must go through the DAO, not raw SQL, for these tables"
+    )

tests/test_db.py

@@ -0,0 +1,998 @@
+"""Tests for db.py, the async SQLite connection wrapper of NestQuest."""
+from __future__ import annotations
+
+import ast
+import asyncio
+import sqlite3
+import threading
+from pathlib import Path
+from typing import Any
+from unittest.mock import AsyncMock, MagicMock
+
+import pytest
+
+from conftest import make_hass
+
+from custom_components.nestquest import db as db_module
+from custom_components.nestquest.db import NestQuestDatabase
+
+
+def _run(coro):
+    return asyncio.new_event_loop().run_until_complete(coro)
+
+
+def _make_hass_mock():
+    hass = MagicMock()
+    hass.async_add_executor_job = AsyncMock(side_effect=(lambda fn, *a: fn(*a)))
+    return hass
+
+
+def _open_db(path) -> tuple[NestQuestDatabase, MagicMock]:
+    hass = _make_hass_mock()
+    database = NestQuestDatabase(hass)
+    _run(database.open(path))
+    return database, hass
+
+
+# ---------------------------------------------------------------------------
+# open(): pragmas, executor delegation, idempotence
+# ---------------------------------------------------------------------------
+
+
+def test_open_enables_wal_journal_mode(tmp_path) -> None:
+    database, _hass = _open_db(tmp_path / "wal.db")
+    row = _run(database.fetch_one("PRAGMA journal_mode"))
+    assert row is not None and str(row[0]).lower() == "wal"
+    _run(database.close())
+
+
+def test_open_enables_foreign_key_enforcement(tmp_path) -> None:
+    database, _hass = _open_db(tmp_path / "fk.db")
+    row = _run(database.fetch_one("PRAGMA foreign_keys"))
+    assert row is not None and int(row[0]) == 1
+    _run(database.close())
+
+
+def test_open_delegates_connection_to_executor(tmp_path) -> None:
+    hass = _make_hass_mock()
+    database = NestQuestDatabase(hass)
+    _run(database.open(tmp_path / "exec.db"))
+    first_call = hass.async_add_executor_job.call_args_list[0]
+    assert callable(first_call.args[0])
+    _run(database.close())
+
+
+def test_open_twice_returns_same_wrapper_without_second_connect(tmp_path) -> None:
+    path = tmp_path / "once.db"
+    hass = _make_hass_mock()
+    database = NestQuestDatabase(hass)
+    first = _run(database.open(path))
+    second = _run(database.open(path))
+    assert first is database
+    assert second is database
+    assert database.connected is True
+    opens = [
+        c
+        for c in hass.async_add_executor_job.call_args_list
+        if getattr(c.args[0], "__name__", "") == "_open"
+    ]
+    assert len(opens) == 1
+    _run(database.close())
+
+
+def test_open_accepts_str_path(tmp_path) -> None:
+    database, _hass = _open_db(str(tmp_path / "str.db"))
+    assert database.connected is True
+    _run(database.close())
+
+
+# ---------------------------------------------------------------------------
+# Executor delegation: every sqlite3 call happens off the event loop
+# ---------------------------------------------------------------------------
+
+
+def test_every_method_routes_sqlite3_through_executor(tmp_path) -> None:
+    """Each wrapper call must go via hass.async_add_executor_job."""
+    database, hass = _open_db(tmp_path / "route.db")
+    calls_before = hass.async_add_executor_job.await_count
+
+    _run(database.execute("CREATE TABLE t (id INTEGER PRIMARY KEY, name TEXT)"))
+    _run(database.execute("INSERT INTO t (name) VALUES (?)", ("a",)))
+    _run(database.execute_many("INSERT INTO t (name) VALUES (?)", [("b",), ("c",)]))
+    row = _run(database.fetch_one("SELECT name FROM t WHERE id = 1"))
+    rows = _run(database.fetch_all("SELECT name FROM t ORDER BY id"))
+
+    assert row == ("a",)
+    assert rows == [("a",), ("b",), ("c",)]
+    assert hass.async_add_executor_job.await_count == calls_before + 5
+    _run(database.close())
+
+
+async def test_every_wrapper_call_awaits_executor_job(tmp_path) -> None:
+    """The executor surface is awaited per wrapper call on a live loop."""
+    hass = _make_hass_mock()
+    database = NestQuestDatabase(hass)
+    await database.open(tmp_path / "loop.db")
+
+    await database.execute("CREATE TABLE t (id INTEGER PRIMARY KEY)")
+    await database.fetch_one("SELECT 1")
+    await database.fetch_all("SELECT 1")
+    await database.execute_many("INSERT INTO t (id) VALUES (?)", [(1,)])
+    async with database.transaction():
+        pass
+
+    assert hass.async_add_executor_job.await_count == 7
+    assert all(callable(c.args[0]) for c in hass.async_add_executor_job.call_args_list)
+    await database.close()
+
+
+async def test_public_methods_return_only_plain_data(tmp_path) -> None:
+    """execute/execute_many return plain dataclasses, never sqlite3 objects."""
+    hass = _make_hass_mock()
+    database = NestQuestDatabase(hass)
+    await database.open(tmp_path / "plain.db")
+    result = await database.execute(
+        "CREATE TABLE t (id INTEGER PRIMARY KEY, name TEXT)"
+    )
+    assert not isinstance(result, (sqlite3.Connection, sqlite3.Cursor))
+    insert = await database.execute("INSERT INTO t (name) VALUES (?)", ("a",))
+    assert not isinstance(insert, (sqlite3.Connection, sqlite3.Cursor))
+    assert insert.rowcount == 1
+    assert insert.lastrowid == 1
+    many = await database.execute_many(
+        "INSERT INTO t (name) VALUES (?)", [("b",), ("c",)]
+    )
+    assert not isinstance(many, (sqlite3.Connection, sqlite3.Cursor))
+    assert many.rowcount == 2
+    row = await database.fetch_one("SELECT name FROM t WHERE id = 1")
+    assert row == ("a",)
+    rows = await database.fetch_all("SELECT name FROM t ORDER BY id")
+    assert rows == [("a",), ("b",), ("c",)]
+    for value in (*rows, row):
+        assert not isinstance(value, sqlite3.Cursor)
+    await database.close()
+
+
+async def test_no_sqlite3_call_on_event_loop_with_real_executor(tmp_path) -> None:
+    """With the conftest hass (real run_in_executor), queries still succeed."""
+    hass, _registry = make_hass()
+    database = NestQuestDatabase(hass)
+    await database.open(tmp_path / "real.db")
+    await database.execute("CREATE TABLE t (id INTEGER PRIMARY KEY)")
+    assert await database.fetch_one("SELECT 1") == (1,)
+    await database.close()
+
+
+async def test_real_executor_never_touches_loop_thread(tmp_path, monkeypatch) -> None:
+    """Every real sqlite3 call must run on a non-event-loop thread.
+
+    sqlite3.connect is instrumented so a proxy wraps the connection and
+    every cursor it hands out; each proxied call records the thread it ran
+    on.  A recorded thread id equal to the event-loop thread would mean a
+    sqlite3 call crossed the executor boundary.
+    """
+    loop_thread = threading.get_ident()
+    recorded: list[int] = []
+    guard = threading.Lock()
+
+    def _note() -> None:
+        with guard:
+            recorded.append(threading.get_ident())
+
+    class _Proxy:
+        """Generic proxy recording the thread of every attribute call."""
+
+        def __init__(self, target: Any) -> None:
+            object.__setattr__(self, "_target", target)
+
+        def __getattr__(self, name: str):
+            attr = getattr(object.__getattribute__(self, "_target"), name)
+            if not callable(attr):
+                return attr
+
+            def _wrapped(*args, **kwargs):
+                _note()
+                result = attr(*args, **kwargs)
+                if isinstance(result, sqlite3.Cursor):
+                    return _Proxy(result)
+                return result
+
+            return _wrapped
+
+    real_connect = sqlite3.connect
+    connect_threads: list[int] = []
+
+    def _traced_connect(*args, **kwargs):
+        _note()
+        connect_threads.append(threading.get_ident())
+        return _Proxy(real_connect(*args, **kwargs))
+
+    monkeypatch.setattr(db_module.sqlite3, "connect", _traced_connect)
+
+    hass, _registry = make_hass()
+    database = NestQuestDatabase(hass)
+    await database.open(tmp_path / "threads.db")
+    await database.execute("CREATE TABLE t (id INTEGER PRIMARY KEY)")
+    await database.execute("INSERT INTO t (id) VALUES (?)", (1,))
+    await database.execute_many("INSERT INTO t (id) VALUES (?)", [(2,), (3,)])
+    assert await database.fetch_one("SELECT id FROM t WHERE id = 1") == (1,)
+    assert await database.fetch_all("SELECT id FROM t") == [(1,), (2,), (3,)]
+    async with database.transaction():
+        await database.execute("INSERT INTO t (id) VALUES (?)", (4,))
+    await database.close()
+
+    assert recorded, "expected at least one recorded sqlite3 call"
+    assert len(connect_threads) == 1, (
+        f"expected exactly one traced sqlite3.connect, got {len(connect_threads)}"
+    )
+    assert loop_thread not in recorded, (
+        f"sqlite3 call ran on the event-loop thread {loop_thread}; "
+        f"recorded threads: {sorted(set(recorded))}"
+    )
+
+
+# ---------------------------------------------------------------------------
+# Source scan: sqlite3.* only inside executor-delegated functions
+# ---------------------------------------------------------------------------
+
+
+def _iter_with_scope(node, chain):
+    """Yield (node, enclosing-function chain), depth-first."""
+    for child in ast.iter_child_nodes(node):
+        yield child, chain
+        next_chain = chain + (child,) if isinstance(
+            child, (ast.FunctionDef, ast.AsyncFunctionDef)
+        ) else chain
+        yield from _iter_with_scope(child, next_chain)
+
+
+def test_db_sqlite3_calls_only_inside_executor_delegated_functions() -> None:
+    """Every sqlite3.* call in db.py sits inside an executor-delegating function.
+
+    A function is executor-delegating when it (or, for nested closures, any of
+    its enclosing functions) passes work to ``hass.async_add_executor_job``.
+    """
+    source = Path(db_module.__file__).read_text(encoding="utf-8")
+    tree = ast.parse(source, filename=str(db_module.__file__))
+
+    delegated = {
+        node.name
+        for node in ast.walk(tree)
+        if isinstance(node, (ast.FunctionDef, ast.AsyncFunctionDef))
+        and any(
+            isinstance(sub, ast.Call)
+            and isinstance(sub.func, ast.Attribute)
+            and sub.func.attr == "async_add_executor_job"
+            for sub in ast.walk(node)
+        )
+    }
+    assert delegated, "expected executor-delegated functions in db.py"
+
+    violations = []
+    for node, chain in _iter_with_scope(tree, ()):
+        if (
+            isinstance(node, ast.Call)
+            and isinstance(node.func, ast.Attribute)
+            and isinstance(node.func.value, ast.Name)
+            and node.func.value.id == "sqlite3"
+            and not any(f.name in delegated for f in chain)
+        ):
+            violations.append((node.lineno, node.func.attr))
+    assert violations == [], (
+        f"Direct sqlite3 calls outside executor-delegated functions: {violations}"
+    )
+
+
+def test_package_wide_sqlite3_scan_excludes_only_db_module() -> None:
+    """The package-wide store scan exempts exactly the db module."""
+    pkg_dir = Path(db_module.__file__).parent
+    scanned = [p.name for p in pkg_dir.glob("*.py") if p.name != "db.py"]
+    assert scanned, "expected other package modules to be scanned"
+    assert "db.py" not in scanned
+
+
+# ---------------------------------------------------------------------------
+# close(): idempotence and post-close errors
+# ---------------------------------------------------------------------------
+
+
+def test_close_is_idempotent(tmp_path) -> None:
+    database, hass = _open_db(tmp_path / "idem.db")
+    _run(database.close())
+    assert database.connected is False
+    _run(database.close())
+    assert database.connected is False
+    assert hass.async_add_executor_job.await_count == 2
+    assert database.rowcount == -1
+    assert database.lastrowid is None
+
+
+def test_operations_after_close_raise_clear_error(tmp_path) -> None:
+    database, _hass = _open_db(tmp_path / "closed.db")
+    _run(database.close())
+
+    async def _txn():
+        async with database.transaction():
+            pass
+
+    with pytest.raises(RuntimeError, match="closed"):
+        _run(database.execute("SELECT 1"))
+    with pytest.raises(RuntimeError, match="closed"):
+        _run(database.fetch_one("SELECT 1"))
+    with pytest.raises(RuntimeError, match="closed"):
+        _run(database.fetch_all("SELECT 1"))
+    with pytest.raises(RuntimeError, match="closed"):
+        _run(database.execute_many("SELECT 1", []))
+    with pytest.raises(RuntimeError, match="closed"):
+        _run(_txn())
+
+
+# ---------------------------------------------------------------------------
+# Transactions: commit on success, rollback on exception
+# ---------------------------------------------------------------------------
+
+
+def test_transaction_commits_on_success(tmp_path) -> None:
+    database, _hass = _open_db(tmp_path / "commit.db")
+    _run(database.execute("CREATE TABLE t (id INTEGER PRIMARY KEY, name TEXT)"))
+
+    async def _block():
+        async with database.transaction():
+            await database.execute("INSERT INTO t (name) VALUES (?)", ("kept",))
+
+    _run(_block())
+    assert _run(database.fetch_all("SELECT name FROM t")) == [("kept",)]
+    _run(database.close())
+
+
+def test_transaction_rolls_back_on_exception(tmp_path) -> None:
+    database, _hass = _open_db(tmp_path / "rollback.db")
+    _run(database.execute("CREATE TABLE t (id INTEGER PRIMARY KEY, name TEXT)"))
+    _run(database.execute("INSERT INTO t (name) VALUES (?)", ("before",)))
+
+    async def _block():
+        with pytest.raises(ValueError, match="boom"):
+            async with database.transaction():
+                await database.execute(
+                    "INSERT INTO t (name) VALUES (?)", ("dropped",)
+                )
+                raise ValueError("boom")
+
+    _run(_block())
+    assert _run(database.fetch_all("SELECT name FROM t")) == [("before",)]
+    _run(database.close())
+
+
+async def test_commit_failure_rolls_back_and_next_transaction_works(
+    tmp_path,
+) -> None:
+    """A COMMIT failure rolls back and leaves the wrapper reusable.
+
+    With PRAGMA defer_foreign_keys=ON a violating insert succeeds inside
+    the transaction and the foreign-key violation only surfaces at COMMIT.
+    The commit error must propagate, the real connection must end up
+    outside any transaction, and the next transaction() plus statement
+    must run cleanly.
+    """
+    hass, _registry = make_hass()
+    database = NestQuestDatabase(hass)
+    await database.open(tmp_path / "deferred.db")
+    await database.execute("CREATE TABLE parent (id INTEGER PRIMARY KEY)")
+    await database.execute(
+        "CREATE TABLE child ("
+        "id INTEGER PRIMARY KEY, "
+        "parent_id INTEGER NOT NULL REFERENCES parent(id))"
+    )
+
+    with pytest.raises(sqlite3.IntegrityError, match="FOREIGN KEY"):
+        async with database.transaction():
+            await database.execute("PRAGMA defer_foreign_keys=ON")
+            await database.execute(
+                "INSERT INTO child (parent_id) VALUES (?)", (999,)
+            )
+
+    assert database._in_transaction is False
+    assert database._tx_task is None
+    assert database._conn is not None
+    assert database._conn.in_transaction is False
+    assert await database.fetch_all("SELECT COUNT(*) FROM child") == [(0,)]
+
+    async with database.transaction():
+        await database.execute("INSERT INTO parent (id) VALUES (?)", (1,))
+        await database.execute(
+            "INSERT INTO child (parent_id) VALUES (?)", (1,)
+        )
+    assert await database.fetch_all("SELECT COUNT(*) FROM child") == [(1,)]
+    await database.close()
+
+
+async def test_cancel_during_open_closes_abandoned_connection(tmp_path) -> None:
+    """NQ-PR12-010: cancel during open() must close the settled connection.
+
+    The _open executor job is gated: the open task is cancelled while the
+    connect is still in flight, then the worker is allowed to complete it
+    anyway.  The settled connection must never be adopted, must be closed
+    through a settled executor-backed close before the cancellation
+    propagates, and a follow-up open() must succeed cleanly.
+    """
+    hass, _registry = make_hass()
+    database = NestQuestDatabase(hass)
+
+    open_started = asyncio.Event()
+    release_open = asyncio.Event()
+    jobs: list[str] = []
+    captured: dict[str, Any] = {}
+    real_add = hass.async_add_executor_job
+
+    async def _gated_add_executor_job(fn, *args, **kwargs):
+        name = getattr(fn, "__name__", "")
+        jobs.append(name)
+        if name == "_open":
+            open_started.set()
+            await release_open.wait()
+        result = await real_add(fn, *args, **kwargs)
+        if name == "_open":
+            captured["conn"] = result
+        return result
+
+    hass.async_add_executor_job = _gated_add_executor_job
+
+    open_task = asyncio.create_task(database.open(tmp_path / "cancel-open.db"))
+    await open_started.wait()
+    open_task.cancel()
+    await asyncio.sleep(0.05)
+    assert database._conn is None, (
+        "the cancelled open adopted a connection that was still settling"
+    )
+    release_open.set()
+    with pytest.raises(asyncio.CancelledError):
+        await open_task
+
+    assert database.connected is False
+    assert "_close_abandoned" in jobs, (
+        "the abandoned connection was not closed via an executor job"
+    )
+    conn = captured.get("conn")
+    assert conn is not None
+
+    def _probe() -> str:
+        try:
+            conn.execute("SELECT 1")
+        except sqlite3.ProgrammingError:
+            return "closed"
+        return "open"
+
+    assert await real_add(_probe) == "closed"
+
+    hass.async_add_executor_job = real_add
+    await database.open(tmp_path / "cancel-open.db")
+    assert database.connected is True
+    assert await database.fetch_one("SELECT 1") == (1,)
+    await database.close()
+
+
+async def test_cancel_during_begin_settles_then_rolls_back(tmp_path) -> None:
+    """NQ-PR12-007: cancel during BEGIN must not leak a stray transaction.
+
+    The BEGIN executor job is gated: the transaction task is cancelled
+    while BEGIN is still in flight, then the worker is allowed to
+    complete it anyway.  The wrapper must keep transaction ownership
+    until the submitted work settles, roll the completed BEGIN back,
+    clear its state, and stay usable for the next transaction.
+    """
+    hass, _registry = make_hass()
+    database = NestQuestDatabase(hass)
+    await database.open(tmp_path / "cancel-begin.db")
+    await database.execute("CREATE TABLE t (id INTEGER PRIMARY KEY, name TEXT)")
+    await database.execute("INSERT INTO t (name) VALUES (?)", ("before",))
+
+    begin_started = asyncio.Event()
+    release_begin = asyncio.Event()
+    real_add = hass.async_add_executor_job
+
+    async def _gated_add_executor_job(fn, *args, **kwargs):
+        if getattr(fn, "__name__", "") == "_begin":
+            begin_started.set()
+            await release_begin.wait()
+        return await real_add(fn, *args, **kwargs)
+
+    hass.async_add_executor_job = _gated_add_executor_job
+
+    async def _txn() -> None:
+        async with database.transaction():
+            await database.execute("INSERT INTO t (name) VALUES (?)", ("kept",))
+
+    txn_task = asyncio.create_task(_txn())
+    await begin_started.wait()
+    txn_task.cancel()
+    await asyncio.sleep(0.05)
+    assert database._in_transaction is True, (
+        "ownership was released while the cancelled BEGIN was still in flight"
+    )
+    release_begin.set()
+    with pytest.raises(asyncio.CancelledError):
+        await txn_task
+
+    assert database._in_transaction is False
+    assert database._tx_task is None
+    assert database._conn is not None
+    assert database._conn.in_transaction is False
+
+    hass.async_add_executor_job = real_add
+    assert await database.fetch_all("SELECT name FROM t ORDER BY id") == [
+        ("before",)
+    ]
+    async with database.transaction():
+        await database.execute("INSERT INTO t (name) VALUES (?)", ("kept",))
+    assert await database.fetch_all("SELECT name FROM t ORDER BY id") == [
+        ("before",),
+        ("kept",),
+    ]
+    await database.close()
+
+
+async def test_cancel_during_commit_settles_then_propagates_cancellation(
+    tmp_path,
+) -> None:
+    """NQ-PR12-007: cancel during COMMIT must not mask the cancellation.
+
+    COMMIT is gated; the task is cancelled while it is in flight and the
+    worker then completes it anyway.  The cancellation must propagate as
+    CancelledError (not be converted by a doomed ROLLBACK of an already
+    committed transaction), the connection must end outside any
+    transaction, and the wrapper must stay usable.
+    """
+    hass, _registry = make_hass()
+    database = NestQuestDatabase(hass)
+    await database.open(tmp_path / "cancel-commit.db")
+    await database.execute("CREATE TABLE t (id INTEGER PRIMARY KEY, name TEXT)")
+
+    commit_started = asyncio.Event()
+    release_commit = asyncio.Event()
+    real_add = hass.async_add_executor_job
+
+    async def _gated_add_executor_job(fn, *args, **kwargs):
+        if getattr(fn, "__name__", "") == "_commit":
+            commit_started.set()
+            await release_commit.wait()
+        return await real_add(fn, *args, **kwargs)
+
+    hass.async_add_executor_job = _gated_add_executor_job
+
+    async def _txn() -> None:
+        async with database.transaction():
+            await database.execute("INSERT INTO t (name) VALUES (?)", ("kept",))
+
+    txn_task = asyncio.create_task(_txn())
+    await commit_started.wait()
+    txn_task.cancel()
+    await asyncio.sleep(0.05)
+    assert database._in_transaction is True, (
+        "ownership was released while the cancelled COMMIT was still in flight"
+    )
+    release_commit.set()
+    with pytest.raises(asyncio.CancelledError):
+        await txn_task
+
+    assert database._in_transaction is False
+    assert database._tx_task is None
+    assert database._conn is not None
+    assert database._conn.in_transaction is False
+
+    hass.async_add_executor_job = real_add
+    assert await database.fetch_all("SELECT name FROM t") == [("kept",)]
+    async with database.transaction():
+        await database.execute("INSERT INTO t (name) VALUES (?)", ("again",))
+    assert await database.fetch_all("SELECT name FROM t ORDER BY id") == [
+        ("kept",),
+        ("again",),
+    ]
+    await database.close()
+
+
+async def test_cancel_during_in_transaction_execute_settles_then_rolls_back(
+    tmp_path,
+) -> None:
+    """NQ-PR12-009: cancel during an in-transaction statement must not race ROLLBACK.
+
+    The in-transaction INSERT executor job is gated: the transaction task
+    is cancelled while the statement is still in flight, then the worker
+    is allowed to complete it anyway.  The ROLLBACK must only run after
+    the statement has settled — while the statement is in flight the
+    transaction is still open — and the cancelled statement's write must
+    not persist.
+    """
+    hass, _registry = make_hass()
+    database = NestQuestDatabase(hass)
+    await database.open(tmp_path / "cancel-execute.db")
+    await database.execute("CREATE TABLE t (id INTEGER PRIMARY KEY, name TEXT)")
+    await database.execute("INSERT INTO t (name) VALUES (?)", ("before",))
+
+    insert_started = asyncio.Event()
+    release_insert = asyncio.Event()
+    real_add = hass.async_add_executor_job
+
+    async def _gated_add_executor_job(fn, *args, **kwargs):
+        if getattr(fn, "__name__", "") == "_execute":
+            insert_started.set()
+            await release_insert.wait()
+        return await real_add(fn, *args, **kwargs)
+
+    hass.async_add_executor_job = _gated_add_executor_job
+
+    async def _txn() -> None:
+        async with database.transaction():
+            await database.execute("INSERT INTO t (name) VALUES (?)", ("lost",))
+
+    txn_task = asyncio.create_task(_txn())
+    await insert_started.wait()
+    txn_task.cancel()
+    await asyncio.sleep(0.05)
+    assert database._in_transaction is True, (
+        "ownership was released while the cancelled statement was in flight"
+    )
+    assert database._conn is not None
+    assert database._conn.in_transaction is True, (
+        "ROLLBACK ran before the cancelled statement settled"
+    )
+    release_insert.set()
+    with pytest.raises(asyncio.CancelledError):
+        await txn_task
+
+    assert database._in_transaction is False
+    assert database._tx_task is None
+    assert database._conn is not None
+    assert database._conn.in_transaction is False
+
+    hass.async_add_executor_job = real_add
+    assert await database.fetch_all("SELECT name FROM t ORDER BY id") == [
+        ("before",)
+    ]
+    async with database.transaction():
+        await database.execute("INSERT INTO t (name) VALUES (?)", ("kept",))
+    assert await database.fetch_all("SELECT name FROM t ORDER BY id") == [
+        ("before",),
+        ("kept",),
+    ]
+    await database.close()
+
+
+async def test_commit_and_rollback_failures_are_both_preserved(tmp_path) -> None:
+    """NQ-PR12-008: both errors survive when COMMIT and ROLLBACK both fail.
+
+    The COMMIT executor call is forced to fail, and the follow-up
+    cleanup ROLLBACK is forced to fail as well.  The raised error must
+    keep both original exceptions inspectable instead of discarding the
+    commit failure behind the rollback failure.
+    """
+    hass, _registry = make_hass()
+    database = NestQuestDatabase(hass)
+    await database.open(tmp_path / "both-fail.db")
+    await database.execute("CREATE TABLE t (id INTEGER PRIMARY KEY)")
+
+    commit_failure = sqlite3.OperationalError("commit exploded")
+    rollback_failure = sqlite3.OperationalError("rollback exploded")
+    real_add = hass.async_add_executor_job
+
+    async def _failing_add_executor_job(fn, *args, **kwargs):
+        name = getattr(fn, "__name__", "")
+        if name == "_commit":
+            raise commit_failure
+        if name == "_cleanup":
+            raise rollback_failure
+        return await real_add(fn, *args, **kwargs)
+
+    hass.async_add_executor_job = _failing_add_executor_job
+
+    with pytest.raises(BaseExceptionGroup) as exc_info:
+        async with database.transaction():
+            pass
+
+    assert commit_failure in exc_info.value.exceptions
+    assert rollback_failure in exc_info.value.exceptions
+    assert database._in_transaction is False
+    assert database._tx_task is None
+    await database.close()
+
+
+async def test_transaction_persists_across_connections(tmp_path) -> None:
+    """A committed transaction is visible to a brand-new connection."""
+    hass, _registry = make_hass()
+    database = NestQuestDatabase(hass)
+    await database.open(tmp_path / "persist.db")
+    await database.execute("CREATE TABLE t (id INTEGER PRIMARY KEY, name TEXT)")
+    async with database.transaction():
+        await database.execute("INSERT INTO t (name) VALUES (?)", ("kept",))
+    await database.close()
+
+    other = NestQuestDatabase(hass)
+    await other.open(tmp_path / "persist.db")
+    assert await other.fetch_all("SELECT name FROM t") == [("kept",)]
+    await other.close()
+
+
+# ---------------------------------------------------------------------------
+# Serialization: one lock per wrapper, no cross-commit interleaving
+# ---------------------------------------------------------------------------
+
+
+async def test_concurrent_writers_do_not_interleave_commits(tmp_path) -> None:
+    """Real-executor proof: nothing commits inside another transaction's span.
+
+    A transaction runner repeatedly counts rows, inserts, and counts again
+    inside BEGIN..COMMIT; the count must grow by exactly one, proving no
+    other writer committed in between even though several writer tasks fire
+    statements concurrently on real executor threads.  Statements issued
+    while a transaction is open queue behind it on the wrapper lock.
+    """
+    hass, _registry = make_hass()
+    database = NestQuestDatabase(hass)
+    await database.open(tmp_path / "serial.db")
+    await database.execute("CREATE TABLE t (kind TEXT, seq INTEGER)")
+    tx_rounds, writers, writer_rounds = 6, 5, 8
+    total = tx_rounds + writers * writer_rounds
+
+    async def _tx_runner() -> None:
+        for rnd in range(tx_rounds):
+            async with database.transaction():
+                rows = await database.fetch_all("SELECT COUNT(*) FROM t")
+                seen = rows[0][0] if rows else -1
+                await database.execute(
+                    "INSERT INTO t (kind, seq) VALUES (?, ?)", ("tx", rnd)
+                )
+                rows = await database.fetch_all("SELECT COUNT(*) FROM t")
+                grown = rows[0][0] if rows else -1
+                if grown != seen + 1:
+                    raise AssertionError(
+                        f"interleaved commit: count {seen} -> {grown} "
+                        f"in tx round {rnd}"
+                    )
+
+    async def _writer(worker: int) -> None:
+        for rnd in range(writer_rounds):
+            await database.execute(
+                "INSERT INTO t (kind, seq) VALUES (?, ?)", ("w", worker)
+            )
+
+    await asyncio.gather(
+        _tx_runner(), *(_writer(w) for w in range(writers))
+    )
+
+    rows = await database.fetch_all("SELECT COUNT(*) FROM t")
+    assert rows[0][0] == total, f"expected {total} rows, got {rows[0][0]}"
+    await database.close()
+
+
+async def test_transaction_span_excludes_concurrent_transaction(tmp_path) -> None:
+    """A second transaction caller is rejected with a clear error."""
+    hass, _registry = make_hass()
+    database = NestQuestDatabase(hass)
+    await database.open(tmp_path / "reject.db")
+    await database.execute("CREATE TABLE t (id INTEGER)")
+
+    started = asyncio.Event()
+
+    async def _first() -> None:
+        async with database.transaction():
+            started.set()
+            await asyncio.sleep(0.05)
+
+    first = asyncio.create_task(_first())
+    await started.wait()
+    with pytest.raises(RuntimeError, match="transaction"):
+        async with database.transaction():
+            pass
+    await first
+    await database.execute("INSERT INTO t (id) VALUES (?)", (1,))
+    assert await database.fetch_one("SELECT id FROM t") == (1,)
+    await database.close()
+
+
+async def test_transaction_blocks_other_statements_until_commit(tmp_path) -> None:
+    """A statement issued during an open transaction queues behind it."""
+    hass, _registry = make_hass()
+    database = NestQuestDatabase(hass)
+    await database.open(tmp_path / "block.db")
+    await database.execute("CREATE TABLE t (id INTEGER PRIMARY KEY, name TEXT)")
+
+    order: list[str] = []
+    started = asyncio.Event()
+    release = asyncio.Event()
+
+    async def _txn() -> None:
+        async with database.transaction():
+            await database.execute("INSERT INTO t (name) VALUES (?)", ("in_tx",))
+            order.append("tx-start")
+            started.set()
+            await release.wait()
+            order.append("tx-end")
+
+    async def _outsider() -> None:
+        await started.wait()
+        await database.execute("INSERT INTO t (name) VALUES (?)", ("after",))
+        order.append("outside")
+
+    txn_task = asyncio.create_task(_txn())
+    await started.wait()
+    outsider_task = asyncio.create_task(_outsider())
+    await asyncio.sleep(0.05)
+    assert order == ["tx-start"], f"outsider ran inside transaction: {order}"
+    release.set()
+    await asyncio.gather(txn_task, outsider_task)
+    assert order == ["tx-start", "tx-end", "outside"]
+    rows = await database.fetch_all("SELECT name FROM t ORDER BY id")
+    assert rows == [("in_tx",), ("after",)]
+    await database.close()
+
+
+async def test_concurrent_transaction_is_rejected_with_clear_error(
+    tmp_path,
+) -> None:
+    """A second concurrent transaction() gets a clear RuntimeError."""
+    hass, _registry = make_hass()
+    database = NestQuestDatabase(hass)
+    await database.open(tmp_path / "concurrent-tx.db")
+    await database.execute("CREATE TABLE t (id INTEGER)")
+
+    started = asyncio.Event()
+
+    async def _first() -> None:
+        async with database.transaction():
+            started.set()
+            await asyncio.sleep(0.05)
+
+    first = asyncio.create_task(_first())
+    await started.wait()
+    with pytest.raises(RuntimeError, match="transaction"):
+        async with database.transaction():
+            pass
+    await first
+    await database.close()
+
+
+async def test_close_waits_for_in_flight_transaction(tmp_path) -> None:
+    """close() serializes: an open transaction finishes before shutdown."""
+    hass, _registry = make_hass()
+    database = NestQuestDatabase(hass)
+    await database.open(tmp_path / "closerace.db")
+    await database.execute("CREATE TABLE t (id INTEGER PRIMARY KEY, name TEXT)")
+
+    started = asyncio.Event()
+    release = asyncio.Event()
+
+    async def _txn() -> None:
+        async with database.transaction():
+            await database.execute("INSERT INTO t (name) VALUES (?)", ("kept",))
+            started.set()
+            await release.wait()
+
+    txn_task = asyncio.create_task(_txn())
+    await started.wait()
+    close_task = asyncio.create_task(database.close())
+    await asyncio.sleep(0.05)
+    assert database.connected is True, "close() raced an open transaction"
+    release.set()
+    await asyncio.gather(txn_task, close_task)
+    assert database.connected is False
+
+    witness = NestQuestDatabase(hass)
+    await witness.open(tmp_path / "closerace.db")
+    assert await witness.fetch_all("SELECT name FROM t") == [("kept",)]
+    await witness.close()
+
+
+async def test_close_during_transaction_from_same_task_is_rejected(
+    tmp_path,
+) -> None:
+    """close() inside its own transaction body raises instead of deadlocking."""
+    hass, _registry = make_hass()
+    database = NestQuestDatabase(hass)
+    await database.open(tmp_path / "selfclose.db")
+    await database.execute("CREATE TABLE t (id INTEGER)")
+    with pytest.raises(RuntimeError, match="transaction"):
+        async with database.transaction():
+            await database.close()
+    assert database.connected is True
+    await database.close()
+
+
+# ---------------------------------------------------------------------------
+# rowcount / lastrowid surface
+# ---------------------------------------------------------------------------
+
+
+def test_rowcount_and_lastrowid_before_any_operation(tmp_path) -> None:
+    database, _hass = _open_db(tmp_path / "unset.db")
+    assert database.rowcount == -1
+    assert database.lastrowid is None
+    _run(database.close())
+
+
+def test_execute_exposes_rowcount_and_lastrowid(tmp_path) -> None:
+    database, _hass = _open_db(tmp_path / "counts.db")
+    _run(database.execute("CREATE TABLE t (id INTEGER PRIMARY KEY, name TEXT)"))
+    _run(database.execute("INSERT INTO t (name) VALUES (?)", ("x",)))
+    assert database.rowcount == 1
+    assert database.lastrowid == 1
+    _run(database.execute("INSERT INTO t (name) VALUES (?)", ("y",)))
+    assert database.rowcount == 1
+    assert database.lastrowid == 2
+    _run(database.close())
+
+
+def test_execute_many_exposes_rowcount(tmp_path) -> None:
+    database, _hass = _open_db(tmp_path / "many.db")
+    _run(database.execute("CREATE TABLE t (id INTEGER PRIMARY KEY, name TEXT)"))
+    _run(database.execute_many("INSERT INTO t (name) VALUES (?)", [("a",), ("b",)]))
+    assert database.rowcount == 2
+    _run(database.execute("INSERT INTO t (name) VALUES (?)", ("c",)))
+    assert database.lastrowid == 3
+    _run(database.close())
+
+
+# ---------------------------------------------------------------------------
+# Lifecycle wiring: opened once per entry, closed on unload
+# ---------------------------------------------------------------------------
+
+
+async def test_setup_entry_opens_database_in_runtime_data(hass, make_entry) -> None:
+    from conftest import wire_entry_to_registry
+
+    from custom_components.nestquest import async_setup_entry, async_unload_entry
+
+    entry = wire_entry_to_registry(make_entry(), hass.registry)
+    assert await async_setup_entry(hass, entry) is True
+    runtime = entry.runtime_data
+    assert runtime.database is not None
+    assert runtime.database.connected is True
+    await async_unload_entry(hass, entry)
+
+
+async def test_unload_entry_closes_database(hass, make_entry) -> None:
+    from conftest import wire_entry_to_registry
+
+    from custom_components.nestquest import async_setup_entry, async_unload_entry
+
+    entry = wire_entry_to_registry(make_entry(), hass.registry)
+    await async_setup_entry(hass, entry)
+    database = entry.runtime_data.database
+    assert database.connected is True
+    assert await async_unload_entry(hass, entry) is True
+    assert database.connected is False
+    with pytest.raises(RuntimeError, match="closed"):
+        await database.fetch_one("SELECT 1")
+
+
+async def test_second_setup_does_not_open_second_connection(hass, make_entry) -> None:
+    from conftest import wire_entry_to_registry
+
+    from custom_components.nestquest import async_setup_entry, async_unload_entry
+
+    entry = wire_entry_to_registry(make_entry(), hass.registry)
+    await async_setup_entry(hass, entry)
+    first = entry.runtime_data.database
+
+    await async_setup_entry(hass, entry)
+    second = entry.runtime_data.database
+
+    assert first is second
+    assert first.connected is True
+    await async_unload_entry(hass, entry)
+
+
+async def test_setup_unload_cycles_reopen_fresh_connection(hass, make_entry) -> None:
+    from conftest import wire_entry_to_registry
+
+    from custom_components.nestquest import async_setup_entry, async_unload_entry
+
+    entry = wire_entry_to_registry(make_entry(), hass.registry)
+    seen: list[NestQuestDatabase] = []
+    for _ in range(3):
+        await async_setup_entry(hass, entry)
+        runtime = entry.runtime_data
+        assert runtime.database.connected is True
+        seen.append(runtime.database)
+        await async_unload_entry(hass, entry)
+        assert runtime.database.connected is False
+    assert len(set(seen)) == 3
+    assert hass.data == {}

tests/test_lifecycle.py

@@ -3,6 +3,8 @@ from __future__ import annotations
 
 import asyncio
 
+import pytest
+
 from conftest import make_config_entry, make_hass, wire_entry_to_registry
 
 from custom_components.nestquest import DOMAIN, async_setup_entry, async_unload_entry
@@ -196,4 +198,61 @@ async def test_setup_awaitable_listener_removal_supported() -> None:
     assert result is True
     assert removed == [True]
     assert hass.data == {}
-    assert entry.runtime_data is None
+    assert entry.runtime_data is None
+
+
+async def test_setup_closes_database_when_listener_registration_fails() -> None:
+    """A listener-registration failure must not leak the opened database."""
+    from custom_components.nestquest.db import NestQuestDatabase
+
+    class _Boom(Exception):
+        pass
+
+    entry = make_config_entry(entry_id="listener-boom")
+    entry.add_update_listener = lambda listener: (_ for _ in ()).throw(_Boom())
+    hass, _registry = make_hass()
+    with pytest.raises(_Boom):
+        await async_setup_entry(hass, entry)
+    assert hass.data.get(DOMAIN, {}) == {}
+    assert not hasattr(entry, "runtime_data")
+
+
+async def test_unload_closes_database_even_when_listener_removal_raises() -> None:
+    """Unload removes the listener, closes the DB in a finally, then raises."""
+    from custom_components.nestquest.db import NestQuestDatabase
+
+    class _RemoveBoom(Exception):
+        pass
+
+    def _remover():
+        raise _RemoveBoom()
+
+    entry = make_config_entry(entry_id="remove-boom")
+    entry.add_update_listener = lambda listener: _remover
+    hass, _registry = make_hass()
+    await async_setup_entry(hass, entry)
+    database = entry.runtime_data.database
+    with pytest.raises(_RemoveBoom):
+        await async_unload_entry(hass, entry)
+    assert database.connected is False, "database leaked despite remover error"
+    assert entry.runtime_data is None
+    assert DOMAIN not in hass.data
+
+
+async def test_setup_applies_all_v1_tables(hass, make_entry) -> None:
+    """Setup applies the full v1 DDL: all four v1 tables exist afterwards."""
+    entry = _wire(make_entry(), hass.registry)
+    assert await async_setup_entry(hass, entry) is True
+    database = entry.runtime_data.database
+    rows = await database.fetch_all(
+        "SELECT name FROM sqlite_master WHERE type = 'table' "
+        "AND name IN ('children', 'admin_users', 'schedule_rules', "
+        "'task_definitions') ORDER BY name"
+    )
+    assert [row[0] for row in rows] == [
+        "admin_users",
+        "children",
+        "schedule_rules",
+        "task_definitions",
+    ]
+    await async_unload_entry(hass, entry)

tests/test_migrations.py

@@ -0,0 +1,677 @@
+"""Tests for migrations.py: the versioned schema migration runner."""
+from __future__ import annotations
+
+import asyncio
+import hashlib
+import logging
+import sqlite3
+from unittest.mock import AsyncMock
+
+import pytest
+
+from custom_components.nestquest.db import NestQuestDatabase
+from custom_components.nestquest.migrations import (
+    MIGRATIONS,
+    VERSION_TABLE,
+    VERSION_TABLE_DDL,
+    apply_migrations,
+    read_schema_version,
+)
+from custom_components.nestquest.schema import SCHEMA_V1_STATEMENTS
+
+
+def _run(coro):
+    return asyncio.new_event_loop().run_until_complete(coro)
+
+
+def _make_hass_mock():
+    from unittest.mock import AsyncMock, MagicMock
+
+    hass = MagicMock()
+    hass.async_add_executor_job = AsyncMock(side_effect=(lambda fn, *a: fn(*a)))
+    return hass
+
+
+def _open_db(path) -> NestQuestDatabase:
+    database = NestQuestDatabase(_make_hass_mock())
+    _run(database.open(path))
+    return database
+
+
+def _migrate(database, migrations=MIGRATIONS):
+    return _run(apply_migrations(database, migrations))
+
+
+def _version(database) -> int:
+    return _run(read_schema_version(database))
+
+
+def _tables(database) -> set[str]:
+    rows = _run(
+        database.fetch_all(
+            "SELECT name FROM sqlite_master WHERE type = 'table' "
+            "AND name NOT LIKE 'sqlite_%'"
+        )
+    )
+    return {row[0] for row in rows}
+
+
+def _counts(database) -> dict[str, int]:
+    """Row counts for every v1 data table plus the version table."""
+    tables = (
+        "children",
+        "admin_users",
+        "schedule_rules",
+        "task_definitions",
+        "presence_schedules",
+        "presence_overrides",
+        "task_instances",
+        "completion_events",
+    )
+    counts = {}
+    for table in tables:
+        row = _run(database.fetch_one(f"SELECT COUNT(*) FROM {table}"))
+        counts[table] = row[0]
+    return counts
+
+
+# ---------------------------------------------------------------------------
+# Fresh file: version 0 -> version 1
+# ---------------------------------------------------------------------------
+
+
+def test_fresh_file_migrates_to_version_1(tmp_path) -> None:
+    database = _open_db(tmp_path / "fresh.db")
+    try:
+        final = _migrate(database)
+        assert final == 1
+        assert _version(database) == 1
+    finally:
+        _run(database.close())
+
+
+def test_fresh_file_migration_creates_all_v1_tables(tmp_path) -> None:
+    database = _open_db(tmp_path / "fresh-tables.db")
+    try:
+        _migrate(database)
+        expected = {
+            "children",
+            "admin_users",
+            "schedule_rules",
+            "task_definitions",
+            "presence_schedules",
+            "presence_overrides",
+            "task_instances",
+            "completion_events",
+            VERSION_TABLE,
+        }
+        assert _tables(database) == expected
+    finally:
+        _run(database.close())
+
+
+def test_missing_version_table_raises_on_direct_read(tmp_path) -> None:
+    database = _open_db(tmp_path / "no-table.db")
+    try:
+        with pytest.raises(sqlite3.OperationalError, match="no such table"):
+            _run(read_schema_version(database))
+        row = _run(
+            database.fetch_one(
+                "SELECT name FROM sqlite_master WHERE type = 'table' "
+                f"AND name = '{VERSION_TABLE}'"
+            )
+        )
+        assert row is None, "read_schema_version must not create the table"
+    finally:
+        _run(database.close())
+
+
+def test_empty_version_table_reads_as_version_0(tmp_path) -> None:
+    database = _open_db(tmp_path / "empty-table.db")
+    try:
+        _run(database.execute(VERSION_TABLE_DDL))
+        assert _version(database) == 0
+    finally:
+        _run(database.close())
+
+
+def test_migration_1_is_the_full_v1_ddl() -> None:
+    assert MIGRATIONS[0] == SCHEMA_V1_STATEMENTS
+    assert len(MIGRATIONS) == 1
+
+
+# ---------------------------------------------------------------------------
+# Idempotence: second start is a no-op
+# ---------------------------------------------------------------------------
+
+
+def test_second_run_applies_nothing_and_keeps_rows(tmp_path) -> None:
+    database = _open_db(tmp_path / "idempotent.db")
+    try:
+        _migrate(database)
+        _run(
+            database.execute(
+                "INSERT INTO children (display_name, created_at) VALUES (?, ?)",
+                ("Ada", "2026-09-13T00:00:00+00:00"),
+            )
+        )
+        _run(
+            database.execute(
+                "INSERT INTO admin_users (ha_user_id, added_at) VALUES (?, ?)",
+                ("user-1", "2026-09-13T00:00:00+00:00"),
+            )
+        )
+        final = _migrate(database)
+        assert final == 1
+        assert _version(database) == 1
+        assert _counts(database)["children"] == 1
+        assert _counts(database)["admin_users"] == 1
+    finally:
+        _run(database.close())
+
+
+def test_second_run_writes_nothing_to_the_file(tmp_path, caplog) -> None:
+    database = _open_db(tmp_path / "noop.db")
+    try:
+        _migrate(database)
+        _run(database.execute("PRAGMA wal_checkpoint(TRUNCATE)"))
+        db_file = tmp_path / "noop.db"
+        wal_file = tmp_path / "noop.db-wal"
+        digest_before = hashlib.sha256(db_file.read_bytes()).hexdigest()
+        mtime_before = db_file.stat().st_mtime_ns
+        wal_digest_before = (
+            hashlib.sha256(wal_file.read_bytes()).hexdigest()
+            if wal_file.exists()
+            else None
+        )
+
+        _migrate(database)
+
+        # A no-op run must not open a write transaction: the main
+        # database file is byte-identical (content hash, not just size)
+        # and untouched (mtime too), and the WAL gained no frames.
+        assert db_file.stat().st_mtime_ns == mtime_before
+        assert (
+            hashlib.sha256(db_file.read_bytes()).hexdigest() == digest_before
+        )
+        if wal_digest_before is None:
+            assert not wal_file.exists()
+        else:
+            assert (
+                hashlib.sha256(wal_file.read_bytes()).hexdigest()
+                == wal_digest_before
+            )
+    finally:
+        _run(database.close())
+
+
+def test_noop_run_logs_no_migration(caplog, tmp_path) -> None:
+    database = _open_db(tmp_path / "noop-log.db")
+    try:
+        _migrate(database)
+        caplog.clear()
+        with caplog.at_level(logging.INFO, logger="custom_components.nestquest.migrations"):
+            _migrate(database)
+        migrated = [
+            r for r in caplog.records if "migrated" in r.getMessage().lower()
+        ]
+        assert migrated == []
+    finally:
+        _run(database.close())
+
+
+def test_noop_run_is_logged_at_debug_level(caplog, tmp_path) -> None:
+    database = _open_db(tmp_path / "noop-debug.db")
+    try:
+        _migrate(database)
+        caplog.clear()
+        with caplog.at_level(logging.DEBUG, logger="custom_components.nestquest.migrations"):
+            _migrate(database)
+        assert any(
+            "already at version 1" in r.getMessage()
+            for r in caplog.records
+        )
+    finally:
+        _run(database.close())
+
+
+# ---------------------------------------------------------------------------
+# Failure atomicity: a failing migration leaves the prior version intact
+# ---------------------------------------------------------------------------
+
+
+def _failing_migrations(prior_statements: list[str]) -> list[list[str]]:
+    """Two-migration list where migration 2 fails mid-application."""
+    return [
+        prior_statements,
+        [
+            "CREATE TABLE IF NOT EXISTS later_table (id INTEGER PRIMARY KEY)",
+            "CREATE TABLE broken (",
+        ],
+    ]
+
+
+def test_failing_migration_rolls_back_to_prior_version(tmp_path) -> None:
+    database = _open_db(tmp_path / "rollback.db")
+    try:
+        # Manually simulate a database at version 1: apply migration 1's
+        # statements directly and stamp version 1 through the runner.
+        _migrate(database)
+        version_row = _run(
+            database.fetch_one(f"SELECT version FROM {VERSION_TABLE}")
+        )
+        assert version_row == (1,)
+
+        with pytest.raises(sqlite3.OperationalError):
+            _migrate(database, _failing_migrations(SCHEMA_V1_STATEMENTS))
+
+        # Version stamp unchanged, statements from the failed migration
+        # absent, and the v1 tables untouched.
+        assert _version(database) == 1
+        assert "later_table" not in _tables(database)
+        assert _counts(database)["children"] == 0
+        assert _counts(database)["completion_events"] == 0
+    finally:
+        _run(database.close())
+
+
+def test_failing_migration_on_fresh_file_leaves_version_0(tmp_path) -> None:
+    database = _open_db(tmp_path / "fresh-rollback.db")
+    try:
+        # The fresh file still reaches migration 2 (the failing one):
+        # migration 1 commits, stamping version 1, before migration 2
+        # fails and rolls back.  The run aborts at version 1 — the last
+        # fully-applied migration — not at version 0.
+        with pytest.raises(sqlite3.OperationalError):
+            _migrate(database, _failing_migrations(SCHEMA_V1_STATEMENTS))
+        assert _version(database) == 1
+        # Migration 2's tables must not survive the failed attempt.
+        assert "later_table" not in _tables(database)
+        # Migration 1's tables do: it committed before the failure.
+        assert "children" in _tables(database)
+        assert "task_instances" in _tables(database)
+    finally:
+        _run(database.close())
+
+
+def test_failed_migration_can_be_retried_after_fix(tmp_path) -> None:
+    database = _open_db(tmp_path / "retry.db")
+    try:
+        _migrate(database)
+        broken = _failing_migrations(SCHEMA_V1_STATEMENTS)
+        with pytest.raises(sqlite3.OperationalError):
+            _migrate(database, broken)
+        # "Fix" the migration and retry: it now applies cleanly.
+        broken[1] = [
+            "CREATE TABLE IF NOT EXISTS later_table (id INTEGER PRIMARY KEY)"
+        ]
+        final = _migrate(database, broken)
+        assert final == 2
+        assert _version(database) == 2
+        assert "later_table" in _tables(database)
+    finally:
+        _run(database.close())
+
+
+def test_failing_migration_error_is_preserved(tmp_path) -> None:
+    database = _open_db(tmp_path / "error-preserved.db")
+    try:
+        with pytest.raises(sqlite3.OperationalError, match="incomplete input"):
+            _migrate(database, _failing_migrations(SCHEMA_V1_STATEMENTS))
+    finally:
+        _run(database.close())
+
+
+# ---------------------------------------------------------------------------
+# Version guard rails
+# ---------------------------------------------------------------------------
+
+
+def test_future_version_is_rejected(tmp_path) -> None:
+    database = _open_db(tmp_path / "future.db")
+    try:
+        _migrate(database)
+        _run(
+            database.execute(
+                f"UPDATE {VERSION_TABLE} SET version = ?", (99,)
+            )
+        )
+        with pytest.raises(RuntimeError, match="newer than"):
+            _migrate(database)
+        # Nothing was modified by the rejected run.
+        assert _version(database) == 99
+    finally:
+        _run(database.close())
+
+
+def test_non_integer_version_raises_runtime_error(tmp_path) -> None:
+    database = _open_db(tmp_path / "string-version.db")
+    try:
+        _run(database.execute(VERSION_TABLE_DDL))
+        # The CHECK enforces version >= 1 but SQLite's loose typing
+        # stores TEXT under an INTEGER-affinity column when it cannot
+        # be losslessly coerced; guard the read path against it.
+        _run(
+            database.execute(
+                f"INSERT INTO {VERSION_TABLE} (id, version) VALUES (1, ?)",
+                ("one",),
+            )
+        )
+        with pytest.raises(RuntimeError, match="not an integer"):
+            _run(read_schema_version(database))
+    finally:
+        _run(database.close())
+
+
+def test_negative_version_read_guard_rejects_below_one() -> None:
+    """The read path rejects sub-1 versions even if storage missed them.
+
+    The VERSION_TABLE CHECK already makes negative/zero unstorable; this
+    exercises the defense-in-depth guard in read_schema_version itself
+    against a database stub returning such a row (e.g. a future schema
+    relaxing the CHECK, or a hand-edited file).
+    """
+    from unittest.mock import AsyncMock, MagicMock
+
+    for bad in (-1, 0):
+        database = MagicMock()
+        database.fetch_one = AsyncMock(return_value=(bad,))
+        with pytest.raises(RuntimeError, match="must be >= 1"):
+            _run(read_schema_version(database))
+
+
+def test_non_integer_version_read_guard_rejects_text() -> None:
+    from unittest.mock import AsyncMock, MagicMock
+
+    for bad in ("one", 1.5, True):
+        database = MagicMock()
+        database.fetch_one = AsyncMock(return_value=(bad,))
+        with pytest.raises(RuntimeError, match="not an integer"):
+            _run(read_schema_version(database))
+
+
+def test_zero_version_row_is_unstorable(tmp_path) -> None:
+    """The CHECK makes sub-1 versions impossible through SQL.
+
+    PRAGMA writable_schema does not bypass CHECKs on ordinary tables,
+    so the negative/zero read guard above is pure defense-in-depth;
+    here we prove the storage-level rule the normal path relies on.
+    """
+    database = _open_db(tmp_path / "zero-version.db")
+    try:
+        _run(database.execute(VERSION_TABLE_DDL))
+        for bad in (0, -1):
+            with pytest.raises(sqlite3.IntegrityError, match="CHECK"):
+                _run(
+                    database.execute(
+                        f"INSERT INTO {VERSION_TABLE} (id, version) "
+                        "VALUES (1, ?)",
+                        (bad,),
+                    )
+                )
+    finally:
+        _run(database.close())
+
+
+def test_version_table_enforces_singleton_row(tmp_path) -> None:
+    database = _open_db(tmp_path / "singleton.db")
+    try:
+        _run(database.execute(VERSION_TABLE_DDL))
+        _run(
+            database.execute(
+                f"INSERT INTO {VERSION_TABLE} (id, version) VALUES (1, 1)"
+            )
+        )
+        with pytest.raises(sqlite3.IntegrityError, match="CHECK"):
+            _run(
+                database.execute(
+                    f"INSERT INTO {VERSION_TABLE} (id, version) "
+                    "VALUES (2, 1)"
+                )
+            )
+    finally:
+        _run(database.close())
+
+
+def test_version_table_check_rejects_version_zero_and_negative(
+    tmp_path,
+) -> None:
+    database = _open_db(tmp_path / "version-check.db")
+    try:
+        _run(database.execute(VERSION_TABLE_DDL))
+        for bad in (0, -1):
+            with pytest.raises(sqlite3.IntegrityError, match="CHECK"):
+                _run(
+                    database.execute(
+                        f"INSERT INTO {VERSION_TABLE} (id, version) "
+                        "VALUES (1, ?)",
+                        (bad,),
+                    )
+                )
+    finally:
+        _run(database.close())
+
+
+def test_concurrent_runners_serialize_and_apply_once(tmp_path) -> None:
+    """Two concurrent runners on one connection apply each step once.
+
+    Deterministic race: runner B starts while runner A is queued into
+    its migration.  A applies everything and stamps; B then acquires
+    the migration lock, re-reads the already-stamped version, and
+    applies nothing.  Without serialization B's transaction() would
+    raise RuntimeError (the wrapper forbids concurrent transactions),
+    so this also proves the queueing works.
+    """
+    migrations = [
+        ["CREATE TABLE IF NOT EXISTS step_a (id INTEGER PRIMARY KEY)"],
+        ["CREATE TABLE IF NOT EXISTS step_b (id INTEGER PRIMARY KEY)"],
+    ]
+    results: dict[str, int] = {}
+
+    async def _main(tmp_name: str) -> None:
+        database = NestQuestDatabase(_make_hass_mock())
+        await database.open(tmp_name)
+        try:
+            # Start A, yield so it acquires the lock and enters its
+            # first transaction, then start B while A is mid-apply.
+            task_a = asyncio.ensure_future(
+                apply_migrations(database, migrations)
+            )
+            await asyncio.sleep(0)
+            task_b = asyncio.ensure_future(
+                apply_migrations(database, migrations)
+            )
+            results["a"], results["b"] = await asyncio.gather(
+                task_a, task_b
+            )
+
+            tables = {
+                row[0]
+                for row in await database.fetch_all(
+                    "SELECT name FROM sqlite_master WHERE type = 'table' "
+                    "AND name NOT LIKE 'sqlite_%'"
+                )
+            }
+            assert {"step_a", "step_b"} <= tables
+            # Each migration's statements ran exactly once: the CREATE
+            # IF NOT EXISTS would hide double-runs, so count via sqlite
+            # sequence/DDL fingerprint instead — re-check version and
+            # that both runners reported the same final version.
+            row = await database.fetch_one(
+                f"SELECT version FROM {VERSION_TABLE}"
+            )
+            assert row == (2,)
+        finally:
+            await database.close()
+
+    loop = asyncio.new_event_loop()
+    try:
+        loop.run_until_complete(_main(str(tmp_path / "concurrent.db")))
+    finally:
+        loop.close()
+
+    assert results["a"] == 2
+    assert results["b"] == 2
+
+
+def test_multiple_pending_migrations_apply_in_order(tmp_path) -> None:
+    database = _open_db(tmp_path / "multi-step.db")
+    try:
+        migrations = [
+            ["CREATE TABLE IF NOT EXISTS step_a (id INTEGER PRIMARY KEY)"],
+            ["CREATE TABLE IF NOT EXISTS step_b (id INTEGER PRIMARY KEY)"],
+            ["CREATE TABLE IF NOT EXISTS step_c (id INTEGER PRIMARY KEY)"],
+        ]
+        final = _run(apply_migrations(database, migrations))
+        assert final == 3
+        assert _version(database) == 3
+        assert {"step_a", "step_b", "step_c"} <= _tables(database)
+    finally:
+        _run(database.close())
+
+
+def test_partial_pending_migrations_resume_from_current_version(
+    tmp_path,
+) -> None:
+    database = _open_db(tmp_path / "resume.db")
+    try:
+        migrations = [
+            ["CREATE TABLE IF NOT EXISTS step_a (id INTEGER PRIMARY KEY)"],
+            ["CREATE TABLE IF NOT EXISTS step_b (id INTEGER PRIMARY KEY)"],
+        ]
+        # Advance to version 1 only, by applying a truncated list of the
+        # same migrations: patch apply_migrations' latest by passing a
+        # single-migration list first, then the full list.
+        _run(apply_migrations(database, migrations[:1]))
+        assert _version(database) == 1
+        final = _run(apply_migrations(database, migrations))
+        assert final == 2
+        assert _version(database) == 2
+        assert "step_b" in _tables(database)
+    finally:
+        _run(database.close())
+
+
+# ---------------------------------------------------------------------------
+# Startup wiring: setup runs the migration runner, not raw DDL
+# ---------------------------------------------------------------------------
+
+
+async def _setup_entry(hass, entry, registry) -> object:
+    from tests.test_lifecycle import _wire  # reuse the established wiring
+
+    entry = _wire(entry, registry)
+    from custom_components.nestquest import async_setup_entry
+
+    await async_setup_entry(hass, entry)
+    return entry
+
+
+async def test_setup_entry_migrates_fresh_database(hass, make_entry) -> None:
+    import sqlite3 as sqlite3_mod
+
+    from custom_components.nestquest.migrations import read_schema_version
+    from custom_components.nestquest.store import async_get_db_path
+
+    entry = await _setup_entry(hass, make_entry(), hass.registry)
+    database = entry.runtime_data.database
+    assert await read_schema_version(database) == 1
+    # The v1 tables exist because the runner applied migration 1.
+    names = {
+        row[0]
+        for row in await database.fetch_all(
+            "SELECT name FROM sqlite_master WHERE type = 'table' "
+            "AND name NOT LIKE 'sqlite_%'"
+        )
+    }
+    assert "children" in names and "completion_events" in names
+    # The version table exists with its singleton row stamped.
+    columns = await database.fetch_all(f"PRAGMA table_info({VERSION_TABLE})")
+    assert [(row[1], row[3]) for row in columns] == [("id", 1), ("version", 1)]
+    db_path = await async_get_db_path(hass)
+    conn = sqlite3_mod.connect(db_path)
+    try:
+        conn.execute(f"INSERT INTO {VERSION_TABLE} (id, version) VALUES (2, 1)")
+        violated = False
+    except sqlite3_mod.IntegrityError:
+        violated = True
+    finally:
+        conn.close()
+    assert violated, "singleton-row CHECK must be live in the setup-created DB"
+    await database.close()
+
+
+async def test_options_reload_reopens_and_rechecks_version(
+    hass, make_entry
+) -> None:
+    """A listener-triggered reload re-runs setup against the same file.
+
+    Unload then setup is the reload lifecycle: the old connection is
+    closed, apply_migrations runs again on the persisted file, keeps
+    version and rows intact, and the reopened connection is live.
+    """
+    from custom_components.nestquest import async_unload_entry
+    from custom_components.nestquest.migrations import read_schema_version
+
+    entry = await _setup_entry(hass, make_entry(), hass.registry)
+    database_a = entry.runtime_data.database
+    await database_a.execute(
+        "INSERT INTO children (display_name, created_at) VALUES (?, ?)",
+        ("Ada", "2026-09-13T00:00:00+00:00"),
+    )
+    assert await async_unload_entry(hass, entry) is True
+    assert not database_a.connected
+
+    entry_reloaded = await _setup_entry(hass, make_entry(), hass.registry)
+    database_b = entry_reloaded.runtime_data.database
+    assert database_b is not database_a
+    try:
+        assert await read_schema_version(database_b) == 1
+        row = await database_b.fetch_one("SELECT COUNT(*) FROM children")
+        assert row == (1,)
+    finally:
+        await database_b.close()
+
+
+async def test_setup_entry_failure_closes_database(
+    hass, make_entry, monkeypatch
+) -> None:
+    """A failing migration closes the opened connection before re-raising.
+
+    Spies on the real wrapper instance: records whether close() ran and
+    whether the connection is left disconnected, rather than inferring
+    from hass.data (a failed setup never stores a runtime record).
+    """
+    import pytest as pytest_module
+
+    import custom_components.nestquest as nestquest_module
+    from custom_components.nestquest.db import NestQuestDatabase
+    from custom_components.nestquest.migrations import (
+        MIGRATIONS as _MIGRATIONS,
+    )
+
+    async def _failing(database, migrations=_MIGRATIONS):
+        raise RuntimeError("boom")
+
+    monkeypatch.setattr(
+        nestquest_module, "apply_migrations", _failing, raising=True
+    )
+
+    close_calls: list[bool] = []
+    original_close = NestQuestDatabase.close
+
+    async def _spy_close(self):
+        close_calls.append(True)
+        return await original_close(self)
+
+    monkeypatch.setattr(NestQuestDatabase, "close", _spy_close)
+
+    entry = make_entry()
+    with pytest_module.raises(RuntimeError, match="boom"):
+        await _setup_entry(hass, entry, hass.registry)
+
+    assert close_calls == [True], (
+        "failed setup must close the connection it opened"
+    )
+    record = hass.data["nestquest"].get(entry.entry_id)
+    assert record is None, "failed setup must not store runtime data"

tests/test_store.py

@@ -100,11 +100,14 @@ def test_executor_helper_creates_directory(tmp_path) -> None:
     assert nested.is_dir()
 
 
-def test_no_sqlite3_import_in_package() -> None:
+def test_no_sqlite3_import_outside_db_module() -> None:
+    """sqlite3 is banned package-wide except db.py, the connection wrapper."""
     pkg_dir = Path(store.__file__).parent
     py_files = list(pkg_dir.glob("*.py"))
     assert py_files
     for py_file in py_files:
+        if py_file.name == "db.py":
+            continue
         tree = ast.parse(py_file.read_text(encoding="utf-8"), filename=str(py_file))
         for node in ast.walk(tree):
             if isinstance(node, ast.Import):