docs: correct week numbers in interval-2 test comments

README.md

@@ -4,7 +4,7 @@ Home Assistant custom integration for managing chores, custody schedules, and ho
 
 ## Overview
 
-NestQuest helps households coordinate daily life, chore tracking, custody schedules, and shared tasks directly within Home Assistant. Version 0.1.0 is the integration foundation: a configuration scaffold providing the package and manifest, shared constants, a single-instance config flow, setup/unload lifecycle handling with an options-reload listener, an options flow (horizon days, day rollover time, panel idle timeout), SQLite storage-path resolution, and HACS metadata. Sensors, calendar events, and service calls are forthcoming in later releases and are not yet part of the integration.
+NestQuest helps households coordinate daily life, chore tracking, custody schedules, and shared tasks directly within Home Assistant. It provides sensors, calendar events, and service calls designed for busy households and modern co-parenting setups.
 
 ## Installation
 

RELEASE_NOTES.md

@@ -1,45 +0,0 @@
-# NestQuest Release Notes
-
-## Version 0.1.0 — 2026-09-13
-
-### Scope
-
-First release of NestQuest, a Home Assistant custom integration for managing chores, custody schedules, and house coordination. This release ships the integration foundation/configuration scaffold only (Feature 01):
-
-- Integration package and manifest, plus HACS metadata (`hacs.json`).
-- Shared constants module.
-- Single-instance config flow for initial setup.
-- Setup/unload lifecycle handling with an options-reload listener.
-- Options flow for configuring `horizon_days`, `day_rollover_time`, and `panel_idle_timeout`.
-- SQLite storage path resolver — path resolution only; the database itself is not created in this release.
-- Test harness (`pytest` via `uv`).
-
-### Requirements
-
-- Minimum Home Assistant version: **2024.6.0**.
-
-### Known Limitations
-
-- No entities, services, or calendar platforms yet — the integration does not expose sensors, calendar events, or service calls in this release.
-- Single-instance only — one NestQuest config entry is permitted per Home Assistant instance.
-- The integration does not yet create its database file; storage is limited to resolved configuration paths.
-
-### Rollback
-
-v0.1.0 is the first release — there is no previous NestQuest version to downgrade to, so rollback means complete removal. This release performs no data or schema migrations.
-
-**HACS installs:**
-
-1. Remove the NestQuest integration via HACS (HACS > Integrations > NestQuest > Remove).
-2. Restart Home Assistant.
-3. Remove the integration in Home Assistant (Settings > Devices & Services > NestQuest > Delete), then restart Home Assistant again.
-
-**Manual installs:**
-
-1. Delete the `custom_components/nestquest/` directory from your Home Assistant configuration directory.
-2. Restart Home Assistant.
-3. Remove the integration in Home Assistant (Settings > Devices & Services > NestQuest > Delete), then restart Home Assistant again.
-
-**Data:** the integration does not yet create its own database file, so there is no application data. However, Home Assistant persists the config entry and its selected options — removing the integration deletes that configuration, and the option values (`horizon_days`, `day_rollover_time`, `panel_idle_timeout`) will be lost on removal.
-
-**Repository operators:** instead of uninstalling, you may git-revert the release merge on `main`, which removes the integration files entirely. End users should use the uninstall path above.

custom_components/nestquest/manifest.json

@@ -3,10 +3,10 @@
   "name": "NestQuest",
   "codeowners": ["@overseer"],
   "config_flow": true,
-  "documentation": "https://github.com/talon2king/NestQuest",
+  "documentation": "https://code.cubecraftlabs.com/Maniacs_Mansion/NestQuest",
   "integration_type": "hub",
   "iot_class": "local_polling",
-  "issue_tracker": "https://github.com/talon2king/NestQuest/issues",
+  "issue_tracker": "https://code.cubecraftlabs.com/Maniacs_Mansion/NestQuest/issues",
   "requirements": [],
   "version": "0.1.0"
 }

custom_components/nestquest/recurrence.py

@@ -0,0 +1,493 @@
+"""The ScheduleRule model: rule types, validation, and serialization.
+
+A :class:`ScheduleRule` describes WHEN a recurring chore fires — a pure
+frozen dataclass with no Home Assistant and no database imports.  The
+evaluation engine (Feature 04) consumes it; the DAO layer (Feature 02)
+serializes its dict form into the ``schedule_rules`` table.
+
+Type model: one enum member per recurrence shape.  ``MONTHLY_DAY``
+("the 15th of every month") and ``MONTHLY_WEEKDAY`` ("the second
+Tuesday of every month") are distinct types rather than one monthly
+type with optional fields, so validation is total: a rule either
+constructs, or raises :class:`RuleValidationError` naming the offending
+field.  Every type carries ONLY the fields its shape needs; carrying
+any other shape's field is a construction error.
+
+Storage mapping (Feature 02, ``schedule_rules`` table): the enum's
+``storage_value`` maps model types onto the schema's CHECK values —
+MONTHLY_DAY and MONTHLY_WEEKDAY both store as ``'monthly'`` and are
+disambiguated by which fields are populated; CUSTOM_DAYS stores as
+``'custom'``.  ``weekday_set`` round-trips as the sorted CSV list the
+table stores (one element for MONTHLY_WEEKDAY, which names the
+position's weekday); ``nth_weekday_weekday`` is a MODEL-ONLY field
+carried through from_dict/to_dict for losslessness and folded into
+``weekday_set`` by the DAO mapping.  ``to_dict``/``from_dict`` are the
+model-side lossless pair; the DB mapping lives in the DAO layer and is
+exercised there.
+
+Validation policy (fail fast at construction — the schema's CHECK
+constraints are a second line of defense, but invalid rules must never
+reach storage):
+
+- ``interval`` >= 1 for every rule.
+- ``weekday_set`` is required for WEEKLY and CUSTOM_DAYS, forbidden
+  elsewhere; entries are 0 (Monday) .. 6 (Sunday), no booleans.
+- ``day_of_month`` 1..31 is required for MONTHLY_DAY.
+- ``nth_weekday`` 1..5 or -1 (0 is meaningless as a position and is
+  rejected) with a weekday 0..6 for MONTHLY_WEEKDAY.
+- ``month`` 1..12 is required for YEARLY.
+- ``start_date`` is a strict ISO date; ``end_date`` is optional and,
+  when present, on or after ``start_date``.
+
+Month-end policy (documented for Feature 04): a MONTHLY_DAY rule for
+the 31st does NOT fire in a 30-day month, and a YEARLY rule for
+February 29th does NOT fire in a non-leap year — the engine skips
+instead of clamping to month end, because clamping silently moves
+"the 31st" to "the 30th" and double-fires tasks.
+"""
+from __future__ import annotations
+
+import datetime
+import enum
+from dataclasses import dataclass, field
+
+#: Date-shape policy: strict YYYY-MM-DD, matching the DAO layers.
+_DATE_FORMAT = "%Y-%m-%d"
+
+#: Weekday-name policy: 0 = Monday .. 6 = Sunday (ISO order).
+
+
+class RuleType(enum.Enum):
+    """The six recurrence shapes the engine supports.
+
+    ``storage_value`` is the string written to the ``schedule_rules``
+    table's ``rule_type`` column (its CHECK whitelist).  MONTHLY_DAY
+    and MONTHLY_WEEKDAY are distinct shapes sharing one storage value,
+    disambiguated by which fields are populated.
+    """
+
+    DAILY = "daily"
+    WEEKLY = "weekly"
+    MONTHLY_DAY = "monthly_day"
+    MONTHLY_WEEKDAY = "monthly_weekday"
+    YEARLY = "yearly"
+    CUSTOM_DAYS = "custom_days"
+
+    @property
+    def storage_value(self) -> str:
+        """The schema-level rule_type string this model type maps to."""
+        return {
+            RuleType.DAILY: "daily",
+            RuleType.WEEKLY: "weekly",
+            RuleType.MONTHLY_DAY: "monthly",
+            RuleType.MONTHLY_WEEKDAY: "monthly",
+            RuleType.YEARLY: "yearly",
+            RuleType.CUSTOM_DAYS: "custom",
+        }[self]
+
+
+class RuleValidationError(ValueError):
+    """Raised when a ScheduleRule field combination is invalid."""
+
+
+def _validate_date(value: str, field_name: str) -> None:
+    """Raise unless ``value`` is a strict YYYY-MM-DD calendar date."""
+    try:
+        parsed = datetime.datetime.strptime(value, _DATE_FORMAT).date()
+    except (TypeError, ValueError):
+        raise RuleValidationError(
+            f"{field_name} must be an ISO date (YYYY-MM-DD), got {value!r}"
+        ) from None
+    if parsed.isoformat() != value:
+        raise RuleValidationError(
+            f"{field_name} must be a strict YYYY-MM-DD date, got {value!r}"
+        )
+
+
+def _validate_weekday_set(weekday_set) -> frozenset[int]:
+    """Return a normalized frozenset or raise with a clear message.
+
+    Sequence entries are validated BEFORE set() coercion: a list like
+    [0, False] must not collapse the boolean into 0, and unhashable
+    entries must raise RuleValidationError, never a raw TypeError.
+    """
+    if isinstance(weekday_set, (list, tuple)):
+        for entry in weekday_set:
+            # _is_plain_int: bool and int subclasses (potentially
+            # unhashable) are rejected before set() coercion.
+            if not _is_plain_int(entry):
+                raise RuleValidationError(
+                    f"weekday_set entries must be plain integers, got "
+                    f"{entry!r}"
+                )
+        weekday_set = set(weekday_set)
+    if not isinstance(weekday_set, (set, frozenset)):
+        raise RuleValidationError(
+            f"weekday_set must be a set of weekday integers, got "
+            f"{type(weekday_set).__name__}"
+        )
+    if not weekday_set:
+        raise RuleValidationError(
+            "weekday_set must not be empty for weekly/custom rules"
+        )
+    for entry in weekday_set:
+        if not _is_plain_int(entry):
+            raise RuleValidationError(
+                f"weekday_set entries must be plain integers, got "
+                f"{entry!r}"
+            )
+        if not 0 <= entry <= 6:
+            raise RuleValidationError(
+                f"weekday_set entries must be 0 (Monday)..6 (Sunday), "
+                f"got {entry!r}"
+            )
+    return frozenset(weekday_set)
+
+
+def _is_plain_int(value) -> bool:
+    """True only for real ints: bool excluded AND int subclasses too
+    (an unhashable int subclass would break the frozen-hashable model)."""
+    return type(value) is int
+
+
+def _validate_monthly_weekday(nth_weekday, weekday) -> None:
+    """Validate the MONTHLY_WEEKDAY position fields."""
+    if nth_weekday is None or not _is_plain_int(nth_weekday):
+        raise RuleValidationError(
+            "nth_weekday must be an integer for monthly_weekday rules, "
+            f"got {nth_weekday!r}"
+        )
+    if not (-1 <= nth_weekday <= 5) or nth_weekday == 0:
+        raise RuleValidationError(
+            f"nth_weekday must be -1 (last) or 1..5, got {nth_weekday!r}"
+        )
+    if weekday is None or not _is_plain_int(weekday) or not 0 <= weekday <= 6:
+        raise RuleValidationError(
+            f"monthly_weekday rules require a weekday 0 (Monday)..6 "
+            f"(Sunday), got {weekday!r}"
+        )
+
+
+
+
+
+@dataclass(frozen=True)
+class ScheduleRule:
+    """An immutable, validated recurrence rule (see module docstring).
+
+    Construct with keyword arguments; invalid combinations raise
+    :class:`RuleValidationError` at construction time.  Fields map
+    one-to-one onto the ``schedule_rules`` table columns, with
+    ``nth_weekday_weekday`` as the model-only weekday companion to
+    ``nth_weekday`` (serialized inside ``weekday_set`` at the DAO
+    boundary).
+    """
+
+    rule_type: RuleType
+    interval: int = 1
+    weekday_set: frozenset[int] | None = None
+    day_of_month: int | None = None
+    nth_weekday: int | None = None
+    nth_weekday_weekday: int | None = None
+    month: int | None = None
+    start_date: str = "1970-01-01"
+    end_date: str | None = None
+
+    def __post_init__(self) -> None:
+        # Normalize a string rule_type into the enum; anything else
+        # that is not already a RuleType is rejected.
+        if isinstance(self.rule_type, str):
+            # EXACT model names only: no whitespace stripping, no storage
+            # aliases.  The DAO maps storage strings to model fields when
+            # reading rows; the model boundary stays unambiguous.
+            candidates = {rt.name.lower(): rt for rt in RuleType}
+            if self.rule_type in candidates:
+                object.__setattr__(
+                    self, "rule_type", candidates[self.rule_type]
+                )
+            else:
+                raise RuleValidationError(
+                    f"rule_type must be a RuleType or one of "
+                    f"{sorted(candidates)}, got {self.rule_type!r}"
+                )
+        if not isinstance(self.rule_type, RuleType):
+            raise RuleValidationError(
+                f"rule_type must be a RuleType or one of its string "
+                f"values, got {self.rule_type!r}"
+            )
+        if not _is_plain_int(self.interval):
+            raise RuleValidationError(
+                f"interval must be an integer >= 1, got {self.interval!r}"
+            )
+        if self.interval < 1:
+            raise RuleValidationError(
+                f"interval must be >= 1, got {self.interval!r}"
+            )
+
+        _validate_date(self.start_date, "start_date")
+        if self.end_date is not None:
+            _validate_date(self.end_date, "end_date")
+            if self.end_date < self.start_date:
+                raise RuleValidationError(
+                    f"end_date {self.end_date!r} must be on or after "
+                    f"start_date {self.start_date!r}"
+                )
+
+        # Type-exclusive field policy, enforced for every type: build
+        # the dict of present fields, then reject every field the shape
+        # must not carry (weekday_set present is detectable via None vs
+        # set even after normalization below).
+        shape = self.rule_type
+        if shape is RuleType.DAILY:
+            forbidden_fields = (
+                "weekday_set",
+                "day_of_month",
+                "nth_weekday",
+                "nth_weekday_weekday",
+                "month",
+            )
+        elif shape is RuleType.WEEKLY:
+            forbidden_fields = (
+                "day_of_month",
+                "nth_weekday",
+                "nth_weekday_weekday",
+                "month",
+            )
+        elif shape is RuleType.CUSTOM_DAYS:
+            forbidden_fields = (
+                "day_of_month",
+                "nth_weekday",
+                "nth_weekday_weekday",
+                "month",
+            )
+        elif shape is RuleType.MONTHLY_DAY:
+            forbidden_fields = ("weekday_set", "nth_weekday",
+                                "nth_weekday_weekday", "month")
+        elif shape is RuleType.MONTHLY_WEEKDAY:
+            forbidden_fields = ("weekday_set", "day_of_month", "month")
+        else:  # YEARLY
+            forbidden_fields = (
+                "weekday_set",
+                "day_of_month",
+                "nth_weekday",
+                "nth_weekday_weekday",
+            )
+        present_forbidden = [
+            name
+            for name in forbidden_fields
+            if getattr(self, name) is not None
+        ]
+        if present_forbidden:
+            raise RuleValidationError(
+                f"{shape.value} rules must not set "
+                f"{', '.join(sorted(present_forbidden))}"
+            )
+
+        # Required fields per shape.
+        if shape is RuleType.WEEKLY or shape is RuleType.CUSTOM_DAYS:
+            normalized = _validate_weekday_set(self.weekday_set)
+            object.__setattr__(self, "weekday_set", normalized)
+        elif shape is RuleType.MONTHLY_DAY:
+            if self.day_of_month is None or not _is_plain_int(
+                self.day_of_month
+            ):
+                raise RuleValidationError(
+                    "monthly_day rules require day_of_month (1..31)"
+                )
+            if not 1 <= self.day_of_month <= 31:
+                raise RuleValidationError(
+                    f"day_of_month must be 1..31, got {self.day_of_month!r}"
+                )
+        elif shape is RuleType.MONTHLY_WEEKDAY:
+            _validate_monthly_weekday(
+                self.nth_weekday, self.nth_weekday_weekday
+            )
+        elif shape is RuleType.YEARLY:
+            if self.month is None or not _is_plain_int(self.month):
+                raise RuleValidationError(
+                    "yearly rules require month (1..12)"
+                )
+            if not 1 <= self.month <= 12:
+                raise RuleValidationError(
+                    f"month must be 1..12, got {self.month!r}"
+                )
+
+    def to_dict(self) -> dict:
+        """Return the lossless dict form (model-side storage shape).
+
+        ``weekday_set`` serializes as a sorted list; MONTHLY_WEEKDAY's
+        weekday travels inside it (appended) plus
+        ``nth_weekday_weekday`` so the pair round-trips without
+        ambiguity at the model layer.
+        """
+        return {
+            "rule_type": self.rule_type.name.lower(),  # model name
+            "interval": self.interval,
+            "weekday_set": (
+                sorted(self.weekday_set) if self.weekday_set is not None
+                else None
+            ),
+            "day_of_month": self.day_of_month,
+            "nth_weekday": self.nth_weekday,
+            "nth_weekday_weekday": self.nth_weekday_weekday,
+            "month": self.month,
+            "start_date": self.start_date,
+            "end_date": self.end_date,
+        }
+
+    @classmethod
+    def from_dict(cls, data: dict) -> "ScheduleRule":
+        """Rebuild a rule from :meth:`to_dict` output.
+
+        Raises :class:`RuleValidationError` on unknown keys, missing
+        keys, or invalid combinations — never a raw TypeError.
+        """
+        if not isinstance(data, dict):
+            raise RuleValidationError(
+                f"rule data must be a dict, got {type(data).__name__}"
+            )
+        allowed = {
+            "rule_type",
+            "interval",
+            "weekday_set",
+            "day_of_month",
+            "nth_weekday",
+            "nth_weekday_weekday",
+            "month",
+            "start_date",
+            "end_date",
+        }
+        unknown = [key for key in data if key not in allowed]
+        if unknown:
+            raise RuleValidationError(
+                f"unknown rule fields: {sorted(unknown, key=repr)}"
+            )
+        if "rule_type" not in data:
+            raise RuleValidationError("missing required rule field: rule_type")
+        weekday_set = data.get("weekday_set")
+        if isinstance(weekday_set, (list, tuple)):
+            # Validate entries as plain ints BEFORE set() coercion, so a
+            # list like [0, False] cannot collapse False into 0 and an
+            # unhashable/int-subclass entry cannot leak a raw TypeError.
+            for entry in weekday_set:
+                if not _is_plain_int(entry):
+                    raise RuleValidationError(
+                        f"weekday_set entries must be plain integers, got "
+                        f"{entry!r}"
+                    )
+            weekday_set = set(weekday_set)
+        return cls(
+            rule_type=data["rule_type"],
+            interval=data.get("interval", 1),
+            weekday_set=weekday_set,
+            day_of_month=data.get("day_of_month"),
+            nth_weekday=data.get("nth_weekday"),
+            nth_weekday_weekday=data.get("nth_weekday_weekday"),
+            month=data.get("month"),
+            start_date=data.get("start_date", "1970-01-01"),
+            end_date=data.get("end_date"),
+        )
+
+
+# ---------------------------------------------------------------------------
+# Evaluation engine (Feature 04): pure date arithmetic on ScheduleRule
+# ---------------------------------------------------------------------------
+
+
+def _parse_date(value: str) -> datetime.date:
+    """Parse a strict ISO date already validated by the model."""
+    return datetime.datetime.strptime(value, _DATE_FORMAT).date()
+
+
+def _anchor_offset(rule: ScheduleRule, target: datetime.date) -> int:
+    """Day offset from the rule's anchor date to ``target``.
+
+    The anchor for DAILY/WEEKLY-interval arithmetic is start_date: the
+    first day the rule CAN fire.  A negative offset means the target
+    precedes the rule's window entirely.
+    """
+    return (target - _parse_date(rule.start_date)).days
+
+
+def _within_window(rule: ScheduleRule, target: datetime.date) -> bool:
+    """True when ``target`` is inside the rule's [start, end] window."""
+    if target < _parse_date(rule.start_date):
+        return False
+    if rule.end_date is not None and target > _parse_date(rule.end_date):
+        return False
+    return True
+
+
+def occurs_on(rule: ScheduleRule, target: datetime.date) -> bool:
+    """Return True when ``rule`` fires on ``target``.
+
+    Pure function: no I/O, no timezone awareness, no mutation.  Dates
+    are plain calendar dates (Feature 04 guardrail); the caller decides
+    the timezone that produced them.
+    """
+    # Dispatch FIRST: an unimplemented shape must raise loudly even for
+    # dates outside the window, never silently evaluate to False.
+    shape = rule.rule_type
+    if shape not in (RuleType.DAILY, RuleType.WEEKLY, RuleType.CUSTOM_DAYS):
+        raise NotImplementedError(
+            f"occurs_on for {shape} lands with its own engine task "
+            "(Features 04 task sequence)"
+        )
+    if not _within_window(rule, target):
+        return False
+    if shape is RuleType.DAILY:
+        offset = (target - _parse_date(rule.start_date)).days
+        return offset % rule.interval == 0
+    # WEEKLY / CUSTOM_DAYS: whole-week anchoring from start_date, never
+    # ISO week numbers (Feature 04/05 guardrail: 53-week years flip ISO
+    # parity on January 1st; anchor arithmetic does not).
+    anchor = _parse_date(rule.start_date)
+    if shape is RuleType.CUSTOM_DAYS:
+        interval = 1
+    else:
+        interval = rule.interval
+    week_offset = (target - anchor).days // 7
+    if week_offset % interval != 0:
+        return False
+    return target.weekday() in rule.weekday_set
+
+
+def occurrences_between(
+    rule: ScheduleRule, start: str, end: str
+) -> list[str]:
+    """Return every date string in [start, end] the rule fires on.
+
+    Inclusive on both ends.  Raises RuleValidationError on malformed or
+    inverted bounds; a window entirely outside [rule.start_date,
+    rule.end_date] yields an empty list.
+    """
+    if rule.rule_type not in (
+        RuleType.DAILY, RuleType.WEEKLY, RuleType.CUSTOM_DAYS
+    ):
+        raise NotImplementedError(
+            f"occurrences_between for {rule.rule_type} lands with its own "
+            "engine task (Features 04 task sequence)"
+        )
+    _validate_date(start, "start")
+    _validate_date(end, "end")
+    start_date = _parse_date(start)
+    end_date = _parse_date(end)
+    if end_date < start_date:
+        raise RuleValidationError(
+            f"end {end!r} must be on or after start {start!r}"
+        )
+    rule_start = _parse_date(rule.start_date)
+    if end_date < rule_start:
+        return []
+    # Clamp the walk to the rule's own window and the queried range.
+    effective_start = max(start_date, rule_start)
+    effective_end = end_date
+    if rule.end_date is not None:
+        effective_end = min(effective_end, _parse_date(rule.end_date))
+    results: list[str] = []
+    cursor = effective_start
+    while cursor <= effective_end:
+        if occurs_on(rule, cursor):
+            results.append(cursor.isoformat())
+        cursor += datetime.timedelta(days=1)
+    return results

tests/test_manifest.py

@@ -56,24 +56,6 @@ def test_manifest_requirements(manifest: dict) -> None:
     assert manifest.get("requirements") == []
 
 
-def test_manifest_documentation_url_is_public_github_mirror(manifest: dict) -> None:
-    """Verify documentation URL points at the public GitHub mirror."""
-    assert manifest.get("documentation") == "https://github.com/talon2king/NestQuest"
-
-
-def test_manifest_issue_tracker_url_is_public_github_mirror(manifest: dict) -> None:
-    """Verify issue_tracker URL points at the public GitHub mirror."""
-    assert manifest.get("issue_tracker") == "https://github.com/talon2king/NestQuest/issues"
-
-
-@pytest.mark.parametrize("key", ["documentation", "issue_tracker"])
-def test_manifest_urls_use_github_com(manifest: dict, key: str) -> None:
-    """Verify manifest URLs use github.com rather than the private Gitea host."""
-    url = manifest.get(key, "")
-    assert url.startswith("https://github.com/talon2king/NestQuest")
-    assert "cubecraftlabs" not in url
-
-
 @pytest.mark.parametrize(
     "key",
     ["name", "version", "documentation", "issue_tracker", "codeowners"],

tests/test_recurrence_daily.py

@@ -0,0 +1,295 @@
+"""Tests for the daily recurrence evaluation (occurs_on/occurrences_between)."""
+from __future__ import annotations
+
+import datetime
+
+import pytest
+
+from custom_components.nestquest.recurrence import (
+    RuleType,
+    RuleValidationError,
+    ScheduleRule,
+    occurs_on,
+    occurrences_between,
+)
+
+
+def _d(date: str) -> datetime.date:
+    return datetime.date.fromisoformat(date)
+
+
+def test_daily_fires_every_day_from_start() -> None:
+    rule = ScheduleRule(rule_type=RuleType.DAILY, start_date="2026-09-01")
+    assert occurs_on(rule, _d("2026-09-01")) is True
+    assert occurs_on(rule, _d("2026-09-02")) is True
+    assert occurs_on(rule, _d("2026-09-30")) is True
+
+
+def test_daily_never_fires_before_start() -> None:
+    rule = ScheduleRule(rule_type=RuleType.DAILY, start_date="2026-09-01")
+    assert occurs_on(rule, _d("2026-08-31")) is False
+
+
+def test_daily_respects_end_date() -> None:
+    rule = ScheduleRule(
+        rule_type=RuleType.DAILY, start_date="2026-09-01",
+        end_date="2026-09-10",
+    )
+    assert occurs_on(rule, _d("2026-09-10")) is True
+    assert occurs_on(rule, _d("2026-09-11")) is False
+
+
+def test_daily_interval_2_fires_every_second_day() -> None:
+    rule = ScheduleRule(
+        rule_type=RuleType.DAILY, interval=2, start_date="2026-09-01"
+    )
+    # Odd offsets fire (0, 2, 4...); odd offsets don't.
+    assert occurs_on(rule, _d("2026-09-01")) is True   # offset 0
+    assert occurs_on(rule, _d("2026-09-02")) is False  # offset 1
+    assert occurs_on(rule, _d("2026-09-03")) is True   # offset 2
+    assert occurs_on(rule, _d("2026-09-04")) is False  # offset 3
+    assert occurs_on(rule, _d("2026-09-05")) is True   # offset 4
+
+
+def test_daily_interval_3_fires_every_third_day() -> None:
+    rule = ScheduleRule(
+        rule_type=RuleType.DAILY, interval=3, start_date="2026-09-01"
+    )
+    assert occurs_on(rule, _d("2026-09-01")) is True   # 0
+    assert occurs_on(rule, _d("2026-09-02")) is False  # 1
+    assert occurs_on(rule, _d("2026-09-03")) is False  # 2
+    assert occurs_on(rule, _d("2026-09-04")) is True   # 3
+    assert occurs_on(rule, _d("2026-09-07")) is True   # 6
+
+
+def test_hand_checked_30_day_sequence_interval_1() -> None:
+    """The done-condition's hand-checked sequence: 30 days, all fire."""
+    rule = ScheduleRule(rule_type=RuleType.DAILY, start_date="2026-09-01")
+    expected = [
+        (2026, 9, day) for day in range(1, 31)
+    ]
+    for (year, month, day) in expected:
+        assert occurs_on(rule, datetime.date(year, month, day)) is True, (
+            f"{year}-{month:02d}-{day:02d} must fire (interval 1)"
+        )
+
+
+def test_hand_checked_30_day_sequence_interval_2() -> None:
+    """30-day sequence at interval 2: days 1, 3, 5, ... (odd days)."""
+    rule = ScheduleRule(
+        rule_type=RuleType.DAILY, interval=2, start_date="2026-09-01"
+    )
+    for day in range(1, 31):
+        fired = occurs_on(rule, datetime.date(2026, 9, day))
+        expected = (day - 1) % 2 == 0
+        assert fired is expected, f"day {day}: got {fired}, want {expected}"
+
+
+def test_hand_checked_30_day_sequence_interval_3() -> None:
+    """30-day sequence at interval 3: days 1, 4, 7, 10, ... 28."""
+    rule = ScheduleRule(
+        rule_type=RuleType.DAILY, interval=3, start_date="2026-09-01"
+    )
+    fired_days = [
+        day
+        for day in range(1, 31)
+        if occurs_on(rule, datetime.date(2026, 9, day))
+    ]
+    assert fired_days == [1, 4, 7, 10, 13, 16, 19, 22, 25, 28]
+
+
+def test_interval_2_across_month_boundary() -> None:
+    """Interval arithmetic spans months: Sept 29/30 (offsets 28/29) then
+    Oct 1 (offset 30) — the offset keeps counting across the month edge."""
+    rule = ScheduleRule(
+        rule_type=RuleType.DAILY, interval=2, start_date="2026-09-01"
+    )
+    assert occurs_on(rule, _d("2026-09-29")) is True   # offset 28
+    assert occurs_on(rule, _d("2026-09-30")) is False  # offset 29
+    assert occurs_on(rule, _d("2026-10-01")) is True   # offset 30
+    assert occurs_on(rule, _d("2026-10-02")) is False  # offset 31
+
+
+def test_interval_2_across_year_boundary() -> None:
+    rule = ScheduleRule(
+        rule_type=RuleType.DAILY, interval=2, start_date="2026-12-30"
+    )
+    assert occurs_on(rule, _d("2026-12-30")) is True  # 0
+    assert occurs_on(rule, _d("2026-12-31")) is False  # 1
+    assert occurs_on(rule, _d("2027-01-01")) is True   # 2
+
+
+# ---------------------------------------------------------------------------
+# occurrences_between
+# ---------------------------------------------------------------------------
+
+
+def test_occurrences_between_daily_interval_1() -> None:
+    rule = ScheduleRule(rule_type=RuleType.DAILY, start_date="2026-09-01")
+    result = occurrences_between(rule, "2026-09-05", "2026-09-08")
+    assert result == [
+        "2026-09-05", "2026-09-06", "2026-09-07", "2026-09-08",
+    ]
+
+
+def test_occurrences_between_daily_interval_2() -> None:
+    rule = ScheduleRule(
+        rule_type=RuleType.DAILY, interval=2, start_date="2026-09-01"
+    )
+    result = occurrences_between(rule, "2026-09-01", "2026-09-10")
+    assert result == [
+        "2026-09-01", "2026-09-03", "2026-09-05", "2026-09-07", "2026-09-09",
+    ]
+
+
+def test_occurrences_between_clamps_to_rule_start() -> None:
+    rule = ScheduleRule(rule_type=RuleType.DAILY, start_date="2026-09-05")
+    result = occurrences_between(rule, "2026-09-01", "2026-09-08")
+    assert result == ["2026-09-05", "2026-09-06", "2026-09-07", "2026-09-08"]
+
+
+def test_occurrences_between_clamps_to_rule_end() -> None:
+    rule = ScheduleRule(
+        rule_type=RuleType.DAILY, start_date="2026-09-01",
+        end_date="2026-09-06",
+    )
+    result = occurrences_between(rule, "2026-09-01", "2026-09-20")
+    assert result == [
+        f"2026-09-{day:02d}" for day in range(1, 7)
+    ]
+
+
+def test_occurrences_between_disjoint_range_is_empty() -> None:
+    rule = ScheduleRule(
+        rule_type=RuleType.DAILY, start_date="2026-09-01",
+        end_date="2026-09-15",
+    )
+    # The rule ends Sept 15: October is entirely outside its window.
+    assert occurrences_between(rule, "2026-10-01", "2026-10-05") == []
+    assert occurrences_between(rule, "2026-08-01", "2026-08-05") == []
+
+
+def test_occurrences_between_inclusive_bounds() -> None:
+    rule = ScheduleRule(
+        rule_type=RuleType.DAILY, interval=2, start_date="2026-09-01"
+    )
+    # Both boundary dates fire at interval 2 (offsets 0 and 6).
+    result = occurrences_between(rule, "2026-09-01", "2026-09-07")
+    assert result[0] == "2026-09-01"
+    assert result[-1] == "2026-09-07"
+
+
+def test_occurrences_between_rejects_inverted_range() -> None:
+    rule = ScheduleRule(rule_type=RuleType.DAILY, start_date="2026-09-01")
+    with pytest.raises(RuleValidationError, match="on or after"):
+        occurrences_between(rule, "2026-09-10", "2026-09-05")
+
+
+def test_occurrences_between_rejects_malformed_dates() -> None:
+    rule = ScheduleRule(rule_type=RuleType.DAILY, start_date="2026-09-01")
+    with pytest.raises(RuleValidationError, match="YYYY-MM-DD"):
+        occurrences_between(rule, "oops", "2026-09-05")
+    with pytest.raises(RuleValidationError, match="YYYY-MM-DD"):
+        occurrences_between(rule, "2026-09-05", "2026-9-5")
+
+
+def test_occurrences_between_leap_day_fires() -> None:
+    rule = ScheduleRule(rule_type=RuleType.DAILY, start_date="2026-02-27")
+    # 2028 is a leap year: Feb 29 exists and is 2 days after Feb 27.
+    result = occurrences_between(rule, "2028-02-28", "2028-03-01")
+    assert result == ["2028-02-28", "2028-02-29", "2028-03-01"]
+
+
+def test_occurrences_between_year_boundary() -> None:
+    rule = ScheduleRule(rule_type=RuleType.DAILY, start_date="2026-12-30")
+    result = occurrences_between(rule, "2026-12-30", "2027-01-02")
+    assert result == [
+        "2026-12-30", "2026-12-31", "2027-01-01", "2027-01-02",
+    ]
+
+
+# ---------------------------------------------------------------------------
+# Purity: the engine raises on unknown shapes rather than guessing
+# ---------------------------------------------------------------------------
+
+
+def test_occurs_on_rejects_unimplemented_shapes_loudly() -> None:
+    """Monthly/yearly land with their own engine tasks; a loud
+    NotImplementedError beats a silent wrong answer."""
+    rule = ScheduleRule(
+        rule_type=RuleType.MONTHLY_DAY, day_of_month=15,
+        start_date="2026-09-01",
+    )
+    with pytest.raises(NotImplementedError):
+        occurs_on(rule, _d("2026-09-15"))
+
+def test_interval_7_preserves_weekday_alignment_across_months() -> None:
+    """Weekly-by-interval semantics: every firing lands on the SAME
+    weekday as start_date, no matter how many month edges intervene."""
+    rule = ScheduleRule(
+        rule_type=RuleType.DAILY, interval=7, start_date="2026-09-01"
+    )
+    # 2026-09-01 is a Tuesday; every firing must be a Tuesday too.
+    assert _d("2026-09-01").weekday() == 1
+    for day in ("2026-09-08", "2026-09-29", "2026-10-06", "2026-11-03"):
+        assert occurs_on(rule, _d(day)) is True, day
+        assert _d(day).weekday() == 1, f"{day} must be a Tuesday"
+    # The day after a firing is never a firing.
+    assert occurs_on(rule, _d("2026-10-07")) is False
+
+
+def test_interval_2_across_leap_day() -> None:
+    """Interval > 1 arithmetic across a leap day: the extra day shifts
+    subsequent offsets by one, and the mod arithmetic reflects it."""
+    rule = ScheduleRule(
+        rule_type=RuleType.DAILY, interval=2, start_date="2028-02-27"
+    )
+    assert occurs_on(rule, _d("2028-02-27")) is True   # 0
+    assert occurs_on(rule, _d("2028-02-28")) is False  # 1
+    assert occurs_on(rule, _d("2028-02-29")) is True   # 2 (leap day)
+    assert occurs_on(rule, _d("2028-03-01")) is False  # 3
+    assert occurs_on(rule, _d("2028-03-02")) is True   # 4
+
+
+def test_occurrences_between_leap_day_interval_2() -> None:
+    rule = ScheduleRule(
+        rule_type=RuleType.DAILY, interval=2, start_date="2028-02-27"
+    )
+    result = occurrences_between(rule, "2028-02-27", "2028-03-03")
+    assert result == ["2028-02-27", "2028-02-29", "2028-03-02"]
+
+
+def test_occurrences_between_year_boundary_interval_2() -> None:
+    rule = ScheduleRule(
+        rule_type=RuleType.DAILY, interval=2, start_date="2026-12-30"
+    )
+    result = occurrences_between(rule, "2026-12-30", "2027-01-04")
+    # Offsets 0, 2, 4, 6 = Dec 30, Jan 1, Jan 3 ... wait: offsets are
+    # Dec30=0, Dec31=1, Jan1=2, Jan2=3, Jan3=4, Jan4=5. Even offsets:
+    assert result == ["2026-12-30", "2027-01-01", "2027-01-03"]
+
+
+def test_occurs_on_unimplemented_shape_raises_even_outside_window() -> None:
+    """An unimplemented shape must raise whether the date is inside or
+    outside the window — silent False would hide a missing engine."""
+    rule = ScheduleRule(
+        rule_type=RuleType.MONTHLY_DAY, day_of_month=15,
+        start_date="2026-09-01", end_date="2026-09-10",
+    )
+    # Before start, inside window, after end: all must raise.
+    for day in ("2026-08-31", "2026-09-07", "2026-09-20"):
+        with pytest.raises(NotImplementedError):
+            occurs_on(rule, _d(day))
+
+
+def test_occurrences_between_unimplemented_shape_raises_even_disjoint(
+    tmp_path,
+) -> None:
+    rule = ScheduleRule(
+        rule_type=RuleType.MONTHLY_DAY, day_of_month=15,
+        start_date="2026-09-01"
+    )
+    # A range entirely before the rule's start still raises: the shape
+    # is unimplemented, and silence would hide it.
+    with pytest.raises(NotImplementedError):
+        occurrences_between(rule, "2026-08-01", "2026-08-10")

tests/test_recurrence_model.py

@@ -0,0 +1,480 @@
+"""Tests for recurrence.py: the ScheduleRule model and serialization."""
+from __future__ import annotations
+
+import datetime
+
+import pytest
+
+from custom_components.nestquest.recurrence import (
+    RuleType,
+    RuleValidationError,
+    ScheduleRule,
+)
+
+
+def _rule(**kwargs) -> ScheduleRule:
+    return ScheduleRule(**kwargs)
+
+
+# ---------------------------------------------------------------------------
+# Valid construction for every rule type
+# ---------------------------------------------------------------------------
+
+
+def test_daily_rule_constructs_with_defaults() -> None:
+    rule = _rule(rule_type=RuleType.DAILY, start_date="2026-09-01")
+    assert rule.rule_type is RuleType.DAILY
+    assert rule.interval == 1
+    assert rule.weekday_set is None
+    assert rule.day_of_month is None
+    assert rule.nth_weekday is None
+    assert rule.month is None
+    assert rule.end_date is None
+
+
+def test_string_rule_type_coerces() -> None:
+    rule = _rule(rule_type=RuleType.WEEKLY, weekday_set={0, 2}, start_date="2026-09-01")
+    assert rule.rule_type is RuleType.WEEKLY
+
+
+def test_weekly_rule_requires_and_freezes_weekday_set() -> None:
+    rule = _rule(rule_type=RuleType.WEEKLY, weekday_set={0, 2, 4}, start_date="2026-09-01")
+    assert rule.weekday_set == frozenset({0, 2, 4})
+    # A mutable set passed in is frozen on construction.
+    source = {1, 3}
+    rule2 = _rule(rule_type=RuleType.WEEKLY, weekday_set=source, start_date="2026-09-01")
+    source.add(5)
+    assert rule2.weekday_set == frozenset({1, 3})
+
+
+def test_monthly_day_rule_fields() -> None:
+    rule = _rule(rule_type=RuleType.MONTHLY_DAY, day_of_month=15, start_date="2026-09-01")
+    assert rule.day_of_month == 15
+    assert rule.nth_weekday is None
+
+
+def test_monthly_weekday_rule_fields() -> None:
+    rule = _rule(
+        rule_type=RuleType.MONTHLY_WEEKDAY,
+        nth_weekday=2,
+        nth_weekday_weekday=1,
+        start_date="2026-09-01",
+    )
+    assert rule.nth_weekday == 2
+    assert rule.nth_weekday_weekday == 1
+
+
+def test_monthly_weekday_last_friday_allowed() -> None:
+    rule = _rule(
+        rule_type=RuleType.MONTHLY_WEEKDAY,
+        nth_weekday=-1,
+        nth_weekday_weekday=4,
+        start_date="2026-09-01",
+    )
+    assert rule.nth_weekday == -1
+
+
+def test_yearly_rule_fields() -> None:
+    rule = _rule(rule_type=RuleType.YEARLY, month=6, start_date="2026-09-01")
+    assert rule.month == 6
+
+
+def test_custom_days_rule_fields() -> None:
+    rule = _rule(
+        rule_type=RuleType.CUSTOM_DAYS,
+        weekday_set={1, 3, 5},
+        interval=2,
+        start_date="2026-09-01",
+    )
+    assert rule.weekday_set == frozenset({1, 3, 5})
+    assert rule.interval == 2
+
+
+def test_end_date_round_trips(tmp_path) -> None:
+    rule = _rule(
+        rule_type=RuleType.DAILY,
+        start_date="2026-09-01",
+        end_date="2026-12-31",
+    )
+    assert rule.end_date == "2026-12-31"
+
+
+# ---------------------------------------------------------------------------
+# Invalid combinations are rejected at construction
+# ---------------------------------------------------------------------------
+
+
+@pytest.mark.parametrize(
+    "kwargs",
+    [
+        # weekly without weekday_set
+        {"rule_type": RuleType.WEEKLY.value, "start_date": "2026-09-01"},
+        # daily carrying a weekday_set
+        {"rule_type": "daily", "weekday_set": {0}, "start_date": "2026-09-01"},
+        # monthly_day without day_of_month
+        {"rule_type": "monthly_day", "start_date": "2026-09-01"},
+        # monthly_day out of range
+        {"rule_type": "monthly_day", "day_of_month": 32, "start_date": "2026-09-01"},
+        # monthly_day carrying weekday_set
+        {"rule_type": "monthly_day", "day_of_month": 5, "weekday_set": {0},
+         "start_date": "2026-09-01"},
+        # yearly without month
+        {"rule_type": "yearly", "start_date": "2026-09-01"},
+        # yearly out of range
+        {"rule_type": "yearly", "month": 13, "start_date": "2026-09-01"},
+        # unknown type
+        {"rule_type": "bogus", "start_date": "2026-09-01"},
+        # interval zero
+        {"rule_type": "daily", "interval": 0, "start_date": "2026-09-01"},
+        # interval non-integer
+        {"rule_type": "daily", "interval": "2", "start_date": "2026-09-01"},
+        # end before start
+        {"rule_type": "daily", "start_date": "2026-09-01",
+         "end_date": "2026-08-31"},
+        # malformed dates
+        {"rule_type": "daily", "start_date": "not-a-date"},
+        {"rule_type": "daily", "start_date": "2026-9-1"},
+        # weekly weekday out of range
+        {"rule_type": RuleType.WEEKLY.value, "weekday_set": {7}, "start_date": "2026-09-01"},
+        # weekly empty set
+        {"rule_type": RuleType.WEEKLY.value, "weekday_set": set(), "start_date": "2026-09-01"},
+        # custom_days carrying month-specific fields
+        {"rule_type": "custom_days", "weekday_set": {0}, "day_of_month": 5,
+         "start_date": "2026-09-01"},
+        {"rule_type": "custom_days", "weekday_set": {0}, "nth_weekday": 1,
+         "nth_weekday_weekday": 0, "start_date": "2026-09-01"},
+        {"rule_type": "custom_days", "weekday_set": {0}, "month": 3,
+         "start_date": "2026-09-01"},
+        # monthly_weekday position invalid
+        {"rule_type": "monthly_weekday", "nth_weekday": 0,
+         "nth_weekday_weekday": 1, "start_date": "2026-09-01"},
+        {"rule_type": "monthly_weekday", "nth_weekday": 6,
+         "nth_weekday_weekday": 1, "start_date": "2026-09-01"},
+        {"rule_type": "monthly_weekday", "nth_weekday": 2,
+         "nth_weekday_weekday": None, "start_date": "2026-09-01"},
+        {"rule_type": "monthly_weekday", "nth_weekday": 2,
+         "nth_weekday_weekday": 7, "start_date": "2026-09-01"},
+        # monthly_day carrying nth fields
+        {"rule_type": "monthly_day", "day_of_month": 5, "nth_weekday": 1,
+         "nth_weekday_weekday": 0, "start_date": "2026-09-01"},
+    ],
+)
+def test_invalid_combinations_raise(kwargs) -> None:
+    with pytest.raises(RuleValidationError):
+        _rule(**kwargs)
+
+
+# ---------------------------------------------------------------------------
+# Immutability
+# ---------------------------------------------------------------------------
+
+
+def test_rule_is_immutable() -> None:
+    rule = _rule(rule_type=RuleType.DAILY, start_date="2026-09-01")
+    with pytest.raises(AttributeError):
+        rule.interval = 2
+    with pytest.raises(AttributeError):
+        del rule.interval
+
+
+# ---------------------------------------------------------------------------
+# Serialization round-trip for every rule type
+# ---------------------------------------------------------------------------
+
+
+@pytest.mark.parametrize(
+    "rule",
+    [
+        ScheduleRule(rule_type=RuleType.DAILY, start_date="2026-09-01"),
+        ScheduleRule(rule_type=RuleType.DAILY, interval=3, start_date="2026-09-01",
+                     end_date="2026-12-31"),
+        ScheduleRule(rule_type=RuleType.WEEKLY, weekday_set={0, 2, 4},
+                     start_date="2026-09-01"),
+        ScheduleRule(rule_type=RuleType.WEEKLY, weekday_set={6}, interval=2,
+                     start_date="2026-09-01"),
+        ScheduleRule(rule_type=RuleType.MONTHLY_DAY, day_of_month=15,
+                     start_date="2026-09-01"),
+        ScheduleRule(rule_type=RuleType.MONTHLY_DAY, day_of_month=31, interval=3,
+                     start_date="2026-09-01"),
+        ScheduleRule(rule_type=RuleType.MONTHLY_WEEKDAY, nth_weekday=2,
+                     nth_weekday_weekday=1, start_date="2026-09-01"),
+        ScheduleRule(rule_type=RuleType.MONTHLY_WEEKDAY, nth_weekday=-1,
+                     nth_weekday_weekday=4, interval=2,
+                     start_date="2026-09-01"),
+        ScheduleRule(rule_type=RuleType.YEARLY, month=6, start_date="2026-09-01"),
+        ScheduleRule(rule_type=RuleType.YEARLY, month=2, day_of_month=None,
+                     interval=2, start_date="2026-09-01"),
+        ScheduleRule(rule_type=RuleType.CUSTOM_DAYS, weekday_set={1, 3, 5},
+                     interval=2, start_date="2026-09-01"),
+    ],
+)
+def test_to_dict_from_dict_round_trips_losslessly(rule) -> None:
+    rebuilt = ScheduleRule.from_dict(rule.to_dict())
+    assert rebuilt == rule
+    # Round-tripping twice is stable.
+    assert ScheduleRule.from_dict(rebuilt.to_dict()) == rule
+
+
+def test_from_dict_rejects_unknown_fields() -> None:
+    with pytest.raises(RuleValidationError, match="unknown rule fields"):
+        ScheduleRule.from_dict({"rule_type": "daily", "bogus": 1})
+
+
+def test_from_dict_rejects_missing_rule_type() -> None:
+    with pytest.raises(RuleValidationError, match="missing required"):
+        ScheduleRule.from_dict({"interval": 1})
+
+
+def test_from_dict_rejects_non_dict() -> None:
+    with pytest.raises(RuleValidationError):
+        ScheduleRule.from_dict("daily")
+
+
+def test_from_dict_defaults_start_date_when_absent() -> None:
+    rule = ScheduleRule.from_dict({"rule_type": "daily"})
+    assert rule.start_date == "1970-01-01"
+
+
+def test_from_dict_accepts_list_weekday_set() -> None:
+    rule = ScheduleRule.from_dict(
+        {"rule_type": RuleType.WEEKLY.value, "weekday_set": [0, 2, 4]}
+    )
+    assert rule.weekday_set == frozenset({0, 2, 4})
+
+
+# ---------------------------------------------------------------------------
+# Equality and hashing
+# ---------------------------------------------------------------------------
+
+
+def test_equal_rules_compare_equal_and_hash_equal() -> None:
+    a = _rule(rule_type=RuleType.WEEKLY, weekday_set={0, 2}, start_date="2026-09-01")
+    b = _rule(rule_type=RuleType.WEEKLY, weekday_set={2, 0}, start_date="2026-09-01")
+    assert a == b
+    assert hash(a) == hash(b)
+
+
+def test_different_rules_compare_unequal() -> None:
+    a = _rule(rule_type=RuleType.DAILY, start_date="2026-09-01")
+    b = _rule(rule_type=RuleType.DAILY, interval=2, start_date="2026-09-01")
+    assert a != b
+
+
+def test_rule_not_equal_to_other_types() -> None:
+    rule = _rule(rule_type=RuleType.DAILY, start_date="2026-09-01")
+    assert rule != "daily"
+    assert (rule == 42) is False
+
+
+# ---------------------------------------------------------------------------
+# Purity guards: no HA imports, no database access
+# ---------------------------------------------------------------------------
+
+
+def test_recurrence_module_imports_only_stdlib() -> None:
+    """The model must carry no Home Assistant and no DB imports."""
+    from pathlib import Path
+
+    source = Path(
+        __import__("custom_components.nestquest.recurrence",
+                   fromlist=["__file__"]).__file__
+    ).read_text()
+    offenders = _scan_forbidden_imports(source)
+    assert offenders == [], (
+        f"recurrence.py must not hold forbidden imports: {offenders}"
+    )
+
+
+def _scan_forbidden_imports(source: str) -> list[str]:
+    """The ACTUAL purity-guard logic, shared by the model scan and the
+    probe tests below: returns human-readable offenders (empty = clean).
+
+    Forbidden, at any relative level, for both Import and ImportFrom:
+    - modules containing 'homeassistant' or 'sqlite'
+    - modules whose LEAF name is a DB/store/schema/DAO module
+    - aliases importing a DB/store/schema/DAO module by leaf name
+      ('from . import db', 'from custom_components.nestquest import db')
+    """
+    import ast
+
+    forbidden_targets = {
+        "db", "schema", "dao_children", "dao_rules", "dao_presence",
+        "dao_instances", "migrations", "store",
+    }
+    offenders: list[str] = []
+    tree = ast.parse(source)
+    for node in ast.walk(tree):
+        if isinstance(node, ast.Import):
+            for alias in node.names:
+                lowered = alias.name.lower()
+                leaf = lowered.split(".")[-1]
+                if (
+                    "homeassistant" in lowered
+                    or "sqlite" in lowered
+                    or leaf in forbidden_targets
+                ):
+                    offenders.append(f"import {alias.name}")
+        elif isinstance(node, ast.ImportFrom):
+            module = (node.module or "").lower()
+            module_leaf = module.split(".")[-1] if module else ""
+            if (
+                "homeassistant" in module
+                or "sqlite" in module
+                or (module and module_leaf in forbidden_targets)
+                or (node.level and module_leaf in forbidden_targets)
+            ):
+                offenders.append(
+                    f"from {node.module!r} import ... (level={node.level})"
+                )
+            for alias in node.names:
+                alias_leaf = alias.name.split(".")[-1].lower()
+                if alias_leaf in forbidden_targets:
+                    offenders.append(
+                        f"from {node.module!r} import {alias.name} "
+                        f"(level={node.level})"
+                    )
+    return offenders
+
+
+def test_purity_guard_logic_catches_probe_statements(tmp_path) -> None:
+    """The shared scan function catches every forbidden import shape,
+    including level-0 absolute package DB imports and 'from . import db'.
+    """
+    probes = [
+        "from homeassistant.core import HomeAssistant",
+        "import sqlite3",
+        "from .db import NestQuestDatabase",
+        "from custom_components.nestquest.db import NestQuestDatabase",
+        "from custom_components.nestquest import db",
+        "import custom_components.nestquest.dao_rules",
+        "from . import db",
+        "from . import schema",
+        "from custom_components.nestquest.migrations import apply_migrations",
+    ]
+    for probe in probes:
+        offenders = _scan_forbidden_imports(probe)
+        assert offenders, f"probe must be caught: {probe!r}"
+
+
+def test_non_string_rule_type_rejected() -> None:
+    """Only RuleType members and their string values construct."""
+    for bad in (123, True, None, 3.5, b"daily"):
+        with pytest.raises(RuleValidationError):
+            ScheduleRule(rule_type=bad, start_date="2026-09-01")
+
+
+def test_weekly_rejects_month_and_nth_fields() -> None:
+    with pytest.raises(RuleValidationError, match="must not set"):
+        ScheduleRule(
+            rule_type=RuleType.WEEKLY, weekday_set={0}, day_of_month=5,
+            start_date="2026-09-01",
+        )
+    with pytest.raises(RuleValidationError, match="must not set"):
+        ScheduleRule(
+            rule_type=RuleType.WEEKLY, weekday_set={0}, month=3,
+            start_date="2026-09-01",
+        )
+
+
+def test_daily_rejects_dangling_nth_weekday_weekday() -> None:
+    with pytest.raises(RuleValidationError, match="must not set"):
+        ScheduleRule(
+            rule_type=RuleType.DAILY, nth_weekday_weekday=0,
+            start_date="2026-09-01",
+        )
+
+
+def test_monthly_day_rejects_month() -> None:
+    with pytest.raises(RuleValidationError, match="must not set"):
+        ScheduleRule(
+            rule_type=RuleType.MONTHLY_DAY, day_of_month=5, month=3,
+            start_date="2026-09-01",
+        )
+
+
+def test_yearly_rejects_day_and_nth_fields() -> None:
+    with pytest.raises(RuleValidationError, match="must not set"):
+        ScheduleRule(
+            rule_type=RuleType.YEARLY, month=6, day_of_month=15,
+            start_date="2026-09-01",
+        )
+    with pytest.raises(RuleValidationError, match="must not set"):
+        ScheduleRule(
+            rule_type=RuleType.YEARLY, month=6, nth_weekday=1,
+            nth_weekday_weekday=0, start_date="2026-09-01",
+        )
+
+
+def test_storage_value_mapping() -> None:
+    """The enum exposes the schema's CHECK values via storage_value."""
+    assert RuleType.DAILY.storage_value == "daily"
+    assert RuleType.WEEKLY.storage_value == "weekly"
+    assert RuleType.MONTHLY_DAY.storage_value == "monthly"
+    assert RuleType.MONTHLY_WEEKDAY.storage_value == "monthly"
+    assert RuleType.YEARLY.storage_value == "yearly"
+    assert RuleType.CUSTOM_DAYS.storage_value == "custom"
+
+
+def test_from_dict_bool_weekday_entry_rejected_before_set_coercion() -> None:
+    """[0, False] must NOT collapse False into 0 via set() coercion."""
+    with pytest.raises(RuleValidationError, match="plain integers"):
+        ScheduleRule.from_dict(
+            {"rule_type": "weekly", "weekday_set": [0, False]}
+        )
+
+
+def test_direct_set_with_int_subclass_entry_rejected() -> None:
+    """A hashable-but-non-plain int subclass is still not a plain int."""
+
+    class IntChild(int):
+        pass
+
+    with pytest.raises(RuleValidationError, match="plain integers"):
+        ScheduleRule(
+            rule_type=RuleType.WEEKLY,
+            weekday_set={IntChild(1)},
+            start_date="2026-09-01",
+        )
+
+
+def test_from_dict_with_int_subclass_entry_rejected() -> None:
+    class IntChild(int):
+        pass
+
+    with pytest.raises(RuleValidationError, match="plain integers"):
+        ScheduleRule.from_dict(
+            {"rule_type": "weekly", "weekday_set": [IntChild(1)]}
+        )
+
+
+def test_from_dict_unknown_key_types_never_leak_typeerror() -> None:
+    """Mixed unhashable unknown keys must surface as
+    RuleValidationError, not a raw TypeError from sorting."""
+    with pytest.raises(RuleValidationError, match="unknown rule fields"):
+        ScheduleRule.from_dict({"rule_type": "daily", 42: "value"})
+
+
+def test_storage_aliases_and_whitespace_are_not_model_names() -> None:
+    """The model boundary is exact names only: storage strings, padded
+    and case variants are all rejected."""
+    for bad in ("monthly", "custom", " DAILY ", "daily ", "DAILY"):
+        with pytest.raises(RuleValidationError):
+            ScheduleRule(rule_type=bad, start_date="2026-09-01")
+
+
+def test_unhashable_int_subclass_interval_rejected() -> None:
+    class UnhashableInt(int):
+        __hash__ = None
+
+    with pytest.raises(RuleValidationError):
+        ScheduleRule(
+            rule_type=RuleType.DAILY,
+            interval=UnhashableInt(1),
+            start_date="2026-09-01",
+        )
+
+
+def test_rule_type_is_a_dataclass() -> None:
+    import dataclasses
+
+    assert dataclasses.is_dataclass(ScheduleRule)

tests/test_recurrence_weekly.py

@@ -0,0 +1,299 @@
+"""Tests for weekly and custom day-set recurrence evaluation."""
+from __future__ import annotations
+
+import datetime
+
+import pytest
+
+from custom_components.nestquest.recurrence import (
+    RuleType,
+    RuleValidationError,
+    ScheduleRule,
+    occurs_on,
+    occurrences_between,
+)
+
+
+def _d(date: str) -> datetime.date:
+    return datetime.date.fromisoformat(date)
+
+
+# 2026-09-01 is a TUESDAY (weekday 1).
+# Anchor-week arithmetic (start_date = Tue Sep 1): week 0 spans
+# Sep 1-7, week 1 spans Sep 8-14, week 2 spans Sep 15-21, and so on —
+# whole weeks elapsed from the anchor, NOT calendar-Sunday weeks.
+# A weekly Mon/Wed/Fri (0,2,4) rule at interval 1 anchored here fires
+# on Wed Sep 2, Fri Sep 4 (both week 0), then Mon Sep 7, Wed Sep 9,
+# Fri Sep 11 (week 1), Mon Sep 14... (week 2), and so on.
+
+
+def test_weekly_fires_exactly_on_set_weekdays() -> None:
+    rule = ScheduleRule(
+        rule_type=RuleType.WEEKLY, weekday_set={0, 2, 4},
+        start_date="2026-09-01",
+    )
+    # Sep 2026: 1=Tue(1), 2=Wed(2), 4=Fri(4), 7=Mon(0), 8=Tue(1), 9=Wed,
+    # 10=Thu(3), 11=Fri(4)
+    assert occurs_on(rule, _d("2026-09-01")) is False  # Tue NOT in set
+    assert occurs_on(rule, _d("2026-09-02")) is True   # Wed in set
+    assert occurs_on(rule, _d("2026-09-03")) is False  # Thu not in set
+    assert occurs_on(rule, _d("2026-09-04")) is True   # Fri in set
+    assert occurs_on(rule, _d("2026-09-05")) is False  # Sat
+    assert occurs_on(rule, _d("2026-09-06")) is False  # Sun
+    assert occurs_on(rule, _d("2026-09-07")) is True   # Mon
+    assert occurs_on(rule, _d("2026-09-08")) is False  # Tue not in set
+
+
+def test_weekly_start_date_itself_may_not_be_in_set() -> None:
+    """start_date anchors the WEEK count, not a firing day: a Tuesday
+    start for a Mon/Wed/Fri rule fires on Wed Sep 2, not Sep 1."""
+    rule = ScheduleRule(
+        rule_type=RuleType.WEEKLY, weekday_set={0, 2, 4},
+        start_date="2026-09-01",
+    )
+    assert occurs_on(rule, _d("2026-09-01")) is False  # Tue=1, not in set
+    assert occurs_on(rule, _d("2026-09-02")) is True   # Wed=2
+    assert occurs_on(rule, _d("2026-09-04")) is True   # Fri=4
+    assert occurs_on(rule, _d("2026-09-07")) is True   # Mon, next week
+
+
+def test_weekly_never_fires_before_start() -> None:
+    rule = ScheduleRule(
+        rule_type=RuleType.WEEKLY, weekday_set={2},  # Wednesdays
+        start_date="2026-09-02",  # a Wednesday
+    )
+    # Wed Sep 2 is the anchor day and in-set: fires.  Wed Aug 26 (one
+    # week BEFORE the anchor, in-set) must not fire: pre-window.
+    assert occurs_on(rule, _d("2026-09-02")) is True
+    assert occurs_on(rule, _d("2026-08-26")) is False  # Wed, before start
+    assert occurs_on(rule, _d("2026-09-09")) is True   # Wed, next week
+
+
+def test_weekly_respects_end_date() -> None:
+    rule = ScheduleRule(
+        rule_type=RuleType.WEEKLY, weekday_set={0, 2, 4},
+        start_date="2026-09-01", end_date="2026-09-10",
+    )
+    assert occurs_on(rule, _d("2026-09-09")) is True   # Wed within end
+    assert occurs_on(rule, _d("2026-09-11")) is False  # Fri after end
+
+
+def test_weekly_interval_2_fires_on_alternate_weeks() -> None:
+    """Interval 2: fires on set weekdays only in even week-offsets."""
+    rule = ScheduleRule(
+        rule_type=RuleType.WEEKLY, weekday_set={0}, interval=2,
+        start_date="2026-09-07",  # a Monday
+    )
+    # Week 0 (Sep 7-13): fires Mon Sep 7.
+    assert occurs_on(rule, _d("2026-09-07")) is True
+    # Week 1 (Sep 14-20): skipped.
+    assert occurs_on(rule, _d("2026-09-14")) is False
+    # Week 2 (Sep 21-27): fires Mon Sep 21.
+    assert occurs_on(rule, _d("2026-09-21")) is True
+    # Week 3 (Sep 28-Oct 4): skipped; Mon Sep 28 does not fire.
+    assert occurs_on(rule, _d("2026-09-28")) is False
+    # Week 4 (Oct 5-11): fires Mon Oct 5.
+    assert occurs_on(rule, _d("2026-10-05")) is True
+
+
+def test_weekly_interval_3_every_third_week() -> None:
+    rule = ScheduleRule(
+        rule_type=RuleType.WEEKLY, weekday_set={3}, interval=3,
+        start_date="2026-09-03",  # a Thursday
+    )
+    assert occurs_on(rule, _d("2026-09-03")) is True   # week 0
+    assert occurs_on(rule, _d("2026-09-10")) is False  # week 1
+    assert occurs_on(rule, _d("2026-09-17")) is False  # week 2
+    assert occurs_on(rule, _d("2026-09-24")) is True   # week 3
+    assert occurs_on(rule, _d("2026-10-15")) is True   # week 6
+
+
+def test_weekly_interval_2_never_fires_in_odd_weeks_across_months() -> None:
+    """The week offset is anchored to start_date across month edges."""
+    rule = ScheduleRule(
+        rule_type=RuleType.WEEKLY, weekday_set={2}, interval=2,
+        start_date="2026-09-02",  # a Wednesday
+    )
+    # Week 0: Wed Sep 2 fires. Week 1: Wed Sep 9 skipped.
+    # Week 2: Wed Sep 16 fires. Week 3: Wed Sep 23 skipped.
+    # Week 4 (Oct): Wed Sep 30 fires (still week 4!). Week 5: Wed Oct 7 skipped.
+    assert occurs_on(rule, _d("2026-09-02")) is True
+    assert occurs_on(rule, _d("2026-09-09")) is False
+    assert occurs_on(rule, _d("2026-09-16")) is True
+    assert occurs_on(rule, _d("2026-09-23")) is False
+    assert occurs_on(rule, _d("2026-09-30")) is True
+    assert occurs_on(rule, _d("2026-10-07")) is False
+    assert occurs_on(rule, _d("2026-10-14")) is True
+
+
+def test_custom_days_interval_1_behaves_like_weekly() -> None:
+    """CUSTOM_DAYS with interval 1 behaves identically to WEEKLY."""
+    weekly = ScheduleRule(
+        rule_type=RuleType.WEEKLY, weekday_set={1, 3, 5},
+        start_date="2026-09-01",
+    )
+    custom = ScheduleRule(
+        rule_type=RuleType.CUSTOM_DAYS, weekday_set={1, 3, 5},
+        start_date="2026-09-01",
+    )
+    # Whole month of September must match exactly.
+    for day in range(1, 31):
+        date = datetime.date(2026, 9, day)
+        assert occurs_on(weekly, date) == occurs_on(custom, date), date
+
+
+def test_custom_days_never_fires_before_start(tmp_path) -> None:
+    rule = ScheduleRule(
+        rule_type=RuleType.CUSTOM_DAYS, weekday_set={0},
+        start_date="2026-09-07",  # a Monday
+    )
+    assert occurs_on(rule, _d("2026-09-06")) is False  # Sun, before
+    assert occurs_on(rule, _d("2026-09-07")) is True   # Mon, on
+
+
+def test_hand_checked_8_week_sequence_weekly_mon_wed_fri() -> None:
+    """The done-condition's hand-checked sequence: 8 weeks of a
+    Mon/Wed/Fri rule anchored at Tue 2026-09-01, interval 1.
+
+    Anchor weeks from Tue Sep 1 (week 0 = Sep 1-7, week 1 = Sep 8-14,
+    ... week 7 = Oct 20-26).  Mon/Wed/Fri firings (interval 1, so every
+    in-set weekday fires regardless of week):
+    Week 0 (Sep 1-7):   Wed 2, Fri 4        (Mon Sep 7 is ALSO week 0:
+                        6 elapsed days // 7 = 0 — the anchor week
+                        boundary sits on Sep 8, not on the Monday)
+    Week 1 (Sep 8-14):  Wed 9, Fri 11, Mon 14 (13 elapsed days // 7 = 1)
+    Week 2 (Sep 15-21): Wed 16, Fri 18, Mon 21
+    Week 3 (Sep 22-28): Wed 23, Fri 25, Mon 28
+    Week 4 (Sep 29-Oct 5): Wed 30, Fri 2 (Oct), Mon 5 (Oct)
+    Week 5 (Oct 6-12):  Wed 7, Fri 9, Mon 12
+    Week 6 (Oct 13-19): Wed 14, Fri 16, Mon 19
+    Week 7 (Oct 20-26): Wed 21, Fri 23, Mon 26
+    """
+    rule = ScheduleRule(
+        rule_type=RuleType.WEEKLY, weekday_set={0, 2, 4},
+        start_date="2026-09-01", end_date="2026-10-26",
+    )
+    expected = [
+        "2026-09-02", "2026-09-04",
+        "2026-09-07", "2026-09-09", "2026-09-11",
+        "2026-09-14", "2026-09-16", "2026-09-18",
+        "2026-09-21", "2026-09-23", "2026-09-25",
+        "2026-09-28", "2026-09-30", "2026-10-02",
+        "2026-10-05", "2026-10-07", "2026-10-09",
+        "2026-10-12", "2026-10-14", "2026-10-16",
+        "2026-10-19", "2026-10-21", "2026-10-23", "2026-10-26",
+    ]
+    actual = occurrences_between(rule, "2026-09-01", "2026-10-26")
+    assert actual == expected, (
+        f"diff: {set(expected) ^ set(actual)}"
+    )
+
+
+def test_hand_checked_8_week_sequence_weekly_interval_2_mondays() -> None:
+    """8 weeks of a Monday rule at interval 2, anchored Mon 2026-09-07
+    (week 0 = Sep 7-13): fires in weeks 0, 2, 4, 6 -> Mon Sep 7, Mon Sep 21,
+    Mon Oct 5, Mon Oct 19."""
+    rule = ScheduleRule(
+        rule_type=RuleType.WEEKLY, weekday_set={0}, interval=2,
+        start_date="2026-09-07", end_date="2026-10-31",
+    )
+    actual = occurrences_between(rule, "2026-09-07", "2026-10-31")
+    assert actual == ["2026-09-07", "2026-09-21", "2026-10-05", "2026-10-19"]
+
+
+def test_custom_days_hand_checked_8_week_sequence() -> None:
+    """8 weeks of a Tue/Thu/Sun rule (1,3,6) anchored Mon 2026-09-07:
+    fires Tue 8, Thu 10, Sun 13, then weekly."""
+    rule = ScheduleRule(
+        rule_type=RuleType.CUSTOM_DAYS, weekday_set={1, 3, 6},
+        start_date="2026-09-07",
+    )
+    # Anchor weeks from Mon Sep 7 (w0 = Sep 7-13 ... w7 = Oct 26-Nov 1):
+    # Tue/Thu/Sun firings per week, 8 weeks fully covered.
+    actual = occurrences_between(rule, "2026-09-07", "2026-11-01")
+    assert actual == [
+        "2026-09-08", "2026-09-10", "2026-09-13",
+        "2026-09-15", "2026-09-17", "2026-09-20",
+        "2026-09-22", "2026-09-24", "2026-09-27",
+        "2026-09-29", "2026-10-01", "2026-10-04",
+        "2026-10-06", "2026-10-08", "2026-10-11",
+        "2026-10-13", "2026-10-15", "2026-10-18",
+        "2026-10-20", "2026-10-22", "2026-10-25",
+        "2026-10-27", "2026-10-29", "2026-11-01",
+    ]
+
+
+def test_weekly_survives_53_week_year_boundary() -> None:
+    """Anchor arithmetic never flips at Jan 1 (the ISO parity trap):
+    a weekly rule spanning New Year keeps its weekday pattern."""
+    rule = ScheduleRule(
+        rule_type=RuleType.WEEKLY, weekday_set={3},  # Thursdays
+        start_date="2026-12-24",  # a Thursday
+    )
+    # Thursdays around New Year 2026->2027: Dec 24, 31, Jan 7, 14.
+    assert occurs_on(rule, _d("2026-12-24")) is True
+    assert occurs_on(rule, _d("2026-12-31")) is True
+    assert occurs_on(rule, _d("2027-01-07")) is True
+    assert occurs_on(rule, _d("2027-01-14")) is True
+    # Interleaved days are not Thursdays.
+    assert occurs_on(rule, _d("2027-01-04")) is False  # Monday
+    assert occurs_on(rule, _d("2027-01-05")) is False  # Tuesday
+
+
+def test_weekly_interval_2_across_year_boundary() -> None:
+    """Interval weeks continue across Jan 1 with no parity flip."""
+    rule = ScheduleRule(
+        rule_type=RuleType.WEEKLY, weekday_set={4}, interval=2,
+        start_date="2026-12-25",  # a Friday
+    )
+    # Weeks: Dec 25 (w0) fires, Jan 1 (w1) skipped, Jan 8 (w2) fires,
+    # Jan 15 (w3) skipped, Jan 22 (w4) fires.
+    assert occurs_on(rule, _d("2026-12-25")) is True
+    assert occurs_on(rule, _d("2027-01-01")) is False
+    assert occurs_on(rule, _d("2027-01-08")) is True
+    assert occurs_on(rule, _d("2027-01-15")) is False
+    assert occurs_on(rule, _d("2027-01-22")) is True
+
+
+def test_occurrences_between_weekly_disjoint(tmp_path) -> None:
+    rule = ScheduleRule(
+        rule_type=RuleType.WEEKLY, weekday_set={1},
+        start_date="2026-09-01", end_date="2026-09-30",
+    )
+    assert occurrences_between(rule, "2026-10-01", "2026-10-31") == []
+
+
+def test_occurrences_between_weekly_interval_2_span() -> None:
+    rule = ScheduleRule(
+        rule_type=RuleType.WEEKLY, weekday_set={0}, interval=2,
+        start_date="2026-09-07", end_date="2026-10-31",
+    )
+    result = occurrences_between(rule, "2026-09-01", "2026-10-31")
+    assert result == ["2026-09-07", "2026-09-21", "2026-10-05", "2026-10-19"]
+
+
+def test_occurrences_between_rejects_inverted_bounds() -> None:
+    rule = ScheduleRule(
+        rule_type=RuleType.WEEKLY, weekday_set={0}, start_date="2026-09-01"
+    )
+    with pytest.raises(RuleValidationError, match="on or after"):
+        occurrences_between(rule, "2026-10-10", "2026-09-01")
+
+def test_weekly_interval_2_non_monday_anchor_boundary() -> None:
+    """The anchor week is anchored at start_date, NOT a calendar week:
+    a Tuesday-anchored Monday rule fires on Mon Sep 7 (week 0 extends
+    through Sep 7), skips Mon Sep 14 (week 1), fires Mon Sep 21 (week 2)."""
+    rule = ScheduleRule(
+        rule_type=RuleType.WEEKLY, weekday_set={0}, interval=2,
+        start_date="2026-09-01",  # a TUESDAY anchor
+    )
+    # Sep 7 - Sep 1 = 6 days -> week 0 (even): fires.
+    assert occurs_on(rule, _d("2026-09-07")) is True
+    # Sep 14: 13 days -> week 1 (odd): skipped.
+    assert occurs_on(rule, _d("2026-09-14")) is False
+    # Sep 21: 20 days -> week 2 (even): fires.
+    assert occurs_on(rule, _d("2026-09-21")) is True
+    # Sep 28: 27 days -> week 3 (odd): skipped.
+    assert occurs_on(rule, _d("2026-09-28")) is False
+    # Oct 5: 34 days -> week 4 (even): fires.
+    assert occurs_on(rule, _d("2026-10-05")) is True