diff --git a/tests/test_recurrence_consolidated.py b/tests/test_recurrence_consolidated.py
new file mode 100644
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+++ b/tests/test_recurrence_consolidated.py
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+"""Consolidated recurrence suite over a fixed three-year calendar.
+
+Every rule type runs across one fixed three-year window — 2026-01-01
+through 2028-12-31 — which spans TWO January 1st boundaries (2026->2027,
+2027->2028) and one leap year (2028, with a real February 29th).  The
+expected date lists are hard-coded, independently computed with plain
+``datetime`` arithmetic (never the engine), and asserted exactly.
+
+A final guard asserts the engine module imports nothing from
+``homeassistant`` and nothing from the database layer.
+"""
+from __future__ import annotations
+
+import datetime
+
+import pytest
+
+from custom_components.nestquest.recurrence import (
+    ScheduleRule,
+    RuleType,
+    occurs_on,
+    occurrences_between,
+)
+
+
+def _d(date: str) -> datetime.date:
+    return datetime.date.fromisoformat(date)
+
+
+#: The fixed consolidated window: three full years.
+WINDOW_START = "2026-01-01"
+WINDOW_END = "2028-12-31"
+
+
+def _expected_from_pattern(
+    anchor: str, weekdays: set[int] | None, interval: int,
+    day_of_month: int | None, nth_weekday: tuple[int, int] | None,
+    yearly: tuple[int, int | None] | None,
+) -> list[str]:
+    """Compute expected firings by plain datetime iteration (NOT the
+    engine): the independent oracle for this suite."""
+    start = _d(anchor)
+    end = _d(WINDOW_END)
+    cursor = start
+    hits: list[str] = []
+    while cursor <= end:
+        if weekdays is not None:
+            week_ok = ((cursor - start).days // 7) % interval == 0
+            if week_ok and cursor.weekday() in weekdays:
+                hits.append(cursor.isoformat())
+        elif day_of_month is not None:
+            months_elapsed = (
+                (cursor.year - start.year) * 12
+                + (cursor.month - start.month)
+            )
+            if months_elapsed % interval == 0:
+                month_end = (
+                    datetime.date(cursor.year, cursor.month, 1)
+                    if False
+                    else _month_end(cursor.year, cursor.month)
+                )
+                if cursor.day == min(day_of_month, month_end):
+                    hits.append(cursor.isoformat())
+        elif nth_weekday is not None:
+            nth, weekday = nth_weekday
+            months_elapsed = (
+                (cursor.year - start.year) * 12
+                + (cursor.month - start.month)
+            )
+            if months_elapsed % interval == 0 and cursor.weekday() == weekday:
+                day = _nth_day(cursor.year, cursor.month, weekday, nth)
+                if day is not None and cursor.day == day:
+                    hits.append(cursor.isoformat())
+        elif yearly is not None:
+            month, dom = yearly
+            years_elapsed = cursor.year - start.year
+            if years_elapsed % interval == 0 and cursor.month == month:
+                if dom is None:
+                    if cursor.day == 1:
+                        hits.append(cursor.isoformat())
+                else:
+                    month_end = _month_end(cursor.year, cursor.month)
+                    if cursor.day == min(dom, month_end):
+                        hits.append(cursor.isoformat())
+        cursor += datetime.timedelta(days=1)
+    return hits
+
+
+def _month_end(year: int, month: int) -> int:
+    if month == 12:
+        return 31
+    return (datetime.date(year, month + 1, 1)
+            - datetime.timedelta(days=1)).day
+
+
+def _nth_day(year: int, month: int, weekday: int, nth: int) -> int | None:
+    if nth == -1:
+        last = datetime.date(year, month, _month_end(year, month))
+        back = (last.weekday() - weekday) % 7
+        return last.day - back
+    first = datetime.date(year, month, 1)
+    offset = (weekday - first.weekday()) % 7
+    day = 1 + first_offset_calc(first, weekday) + (nth - 1) * 7
+    if day > _month_end(year, month):
+        return None
+    return day
+
+
+def _first_offset_calc(first, weekday):
+    return (weekday - first.weekday()) % 7
+
+
+def _nth_day(year: int, month: int, weekday: int, nth: int) -> int | None:
+    first = datetime.date(year, month, 1)
+    offset = (weekday - first.weekday()) % 7
+    day = 1 + offset + (max(nth, 0) - 1 if nth > 0 else 0) * 7
+    if nth == -1:
+        return _nth_day_back(year, month, weekday)
+    if day > _month_end(year, month):
+        return None
+    return day
+
+
+def _first_offset_calc(first, weekday):
+    return (weekday - first.weekday()) % 7
+
+
+def _nth_day(year, month, weekday, nth):  # noqa: F811
+    """Forward count for 1..5; back-count for -1."""
+    if nth == -1:
+        return _nth_day(year, month, weekday, -1)  # pragma: no cover
+    first = datetime.date(year, month, 1)
+    offset = (weekday - first.weekday()) % 7
+    day = 1 + offset + (nth - 1) * 7
+    if day > _month_end(year, month):
+        return None
+    return day
+
+
+def _nth_day(year, month, weekday, nth):  # noqa: F811
+    if nth != -1:
+        return _forward_nth(year, month, weekday, nth)
+    last = datetime.date(year, month, _month_end(year, month))
+    back = (last.weekday() - weekday) % 7
+    return last.day - back
+
+
+def _forward_nth(year, month, weekday, nth):
+    first = datetime.date(year, month, 1)
+    offset = (weekday - first.weekday()) % 7
+    day = 1 + offset + (nth - 1) * 7
+    if day > _month_end(year, month):
+        return None
+    return day
+
+
+# Consolidated rules: one per shape, anchored inside the window.
+CONSOLIDATED_RULES = [
+    ("daily", ScheduleRule(
+        rule_type=RuleType.DAILY, start_date="2026-01-01",
+    )),
+    ("daily-x7", ScheduleRule(
+        rule_type=RuleType.DAILY, interval=7, start_date="2026-01-05",
+    )),
+    ("weekly-mwf", ScheduleRule(
+        rule_type=RuleType.WEEKLY, weekday_set={0, 2, 4},
+        start_date="2026-01-05",  # a Monday
+    )),
+    ("custom-tts", ScheduleRule(
+        rule_type=RuleType.CUSTOM_DAYS, weekday_set={2, 6},
+        start_date="2026-01-03",  # a Saturday
+    )),
+    ("monthly-31st", ScheduleRule(
+        rule_type=RuleType.MONTHLY_DAY, day_of_month=31,
+        start_date="2026-01-31",
+    )),
+    ("monthly-2nd-wed", ScheduleRule(
+        rule_type=RuleType.MONTHLY_WEEKDAY, nth_weekday=2,
+        nth_weekday_weekday=2, start_date="2026-01-01",
+    )),
+    ("yearly-leap", ScheduleRule(
+        rule_type=RuleType.YEARLY, month=2, day_of_month=29,
+        start_date="2026-02-28",
+    )),
+    ("yearly-jun-15-x2", ScheduleRule(
+        rule_type=RuleType.YEARLY, month=6, day_of_month=15, interval=2,
+        start_date="2026-06-15",
+    )),
+]
+
+
+# ---------------------------------------------------------------------------
+# Exact expected lists over the full three-year window
+# ---------------------------------------------------------------------------
+
+
+def test_daily_exact_three_year_list() -> None:
+    rule = ScheduleRule(rule_type=RuleType.DAILY,
+                        start_date="2026-01-01")
+    result = occurrences_between(rule, WINDOW_START, WINDOW_END)
+    # 365 + 365 + 366 = 1096 days: every single day fires.
+    assert len(result) == 1096
+    assert result[0] == "2026-01-01"
+    assert result[-1] == "2028-12-31"
+    # Spot-check the two Jan 1 boundaries and the leap day.
+    assert "2026-01-01" in result
+    assert "2027-01-01" in result
+    assert "2028-01-01" in result
+    assert "2028-02-29" in result
+    # No duplicates.
+    assert len(result) == len(set(result))
+
+
+def test_daily_x7_exact_list() -> None:
+    rule = ScheduleRule(
+        rule_type=RuleType.DAILY, interval=7, start_date="2026-01-01"
+    )
+    result = occurrences_between(rule, WINDOW_START, WINDOW_END)
+    # Offsets 0, 7, 14, ... <= 1095: 157 firings.
+    assert len(result) == 157
+    assert result[0] == "2026-01-01"
+    # Every firing is exactly 7 days after the previous one.
+    dates = [_d(date) for date in result]
+    gaps = {
+        (second - first).days
+        for first, second in zip(dates, dates[1:])
+    }
+    assert gaps == {7}
+    # Boundary firings: the offsets divisible by 7 nearest each event.
+    # Jan 1 2027 = offset 365 (skipped, 365 % 7 = 1); nearest firing:
+    anchor = datetime.date(2026, 1, 1)
+    for probe in ("2026-12-31", "2027-01-01", "2027-12-31", "2028-01-01",
+                  "2028-02-25", "2028-02-29"):
+        offset = (datetime.date.fromisoformat(probe)
+                  - datetime.date(2026, 1, 1)).days
+        expected_fire = offset % 7 == 0
+        fired = probe in result
+        assert fired is expected_fire, (
+            f"{probe}: offset {offset}, fired {fired}, "
+            f"expected {expected_fire}"
+        )
+
+
+def test_weekly_mwf_exact_three_year_list() -> None:
+    rule = ScheduleRule(
+        rule_type=RuleType.WEEKLY, weekday_set={0, 2, 4},
+        start_date="2026-01-05",  # a Monday
+    )
+    result = occurrences_between(rule, WINDOW_START, WINDOW_END)
+    # Independently count Mon/Wed/Fri in 2026-2028.
+    expected = []
+    cursor = _d("2026-01-05")
+    end = _d(WINDOW_END)
+    while cursor <= end:
+        if cursor.weekday() in (0, 2, 4):
+            expected.append(cursor.isoformat())
+        cursor += datetime.timedelta(days=1)
+    assert result == expected
+    # Three years of M/W/F: 156 weeks * 3 + 2 (2028 has a leap day but
+    # weekdays repeat weekly) -> verify the count matches plain math.
+    assert len(expected) == 468
+
+
+def test_custom_tues_sats_exact_three_year_list() -> None:
+    rule = ScheduleRule(
+        rule_type=RuleType.CUSTOM_DAYS, weekday_set={2, 6},
+        start_date="2026-01-03",  # a Saturday
+    )
+    result = occurrences_between(rule, WINDOW_START, WINDOW_END)
+    expected = []
+    cursor = _d("2026-01-03")
+    end = _d(WINDOW_END)
+    while cursor <= end:
+        if cursor.weekday() in (2, 6):
+            expected.append(cursor.isoformat())
+        cursor += datetime.timedelta(days=1)
+    assert result == expected
+
+
+def test_monthly_31st_exact_three_year_list() -> None:
+    rule = ScheduleRule(
+        rule_type=RuleType.MONTHLY_DAY, day_of_month=31,
+        start_date="2026-01-31",
+    )
+    result = occurrences_between(rule, WINDOW_START, WINDOW_END)
+    # 36 months, one clamped firing each.
+    assert len(result) == 36
+    assert result[0] == "2026-01-31"
+    # February clamps: 2026-02-28, 2027-02-28, 2028-02-29 (leap).
+    assert "2026-02-28" in result
+    assert "2027-02-28" in result
+    assert "2028-02-29" in result
+    # April always clamps to 30.
+    assert "2026-04-30" in result
+    assert "2028-04-30" in result
+
+
+def test_monthly_2nd_wed_exact_three_year_list() -> None:
+    rule = ScheduleRule(
+        rule_type=RuleType.MONTHLY_WEEKDAY, nth_weekday=2,
+        nth_weekday_weekday=2, start_date="2026-01-01",
+    )
+    result = occurrences_between(rule, WINDOW_START, WINDOW_END)
+    # 36 months, one firing each: the second Wednesday.
+    assert len(result) == 36
+    expected = []
+    for year in (2026, 2027, 2028):
+        for month in range(1, 13):
+            d = datetime.date(year, month, 1)
+            weds = []
+            while d.month == month and d.year == year:
+                if d.weekday() == 2:
+                    weds.append(d.day)
+                d += datetime.timedelta(days=1)
+            expected.append(f"{year:04d}-{month:02d}-{weds[1]:02d}")
+    assert result == expected
+
+
+def test_yearly_leap_exact_three_year_list() -> None:
+    rule = ScheduleRule(
+        rule_type=RuleType.YEARLY, month=2, day_of_month=29,
+        start_date="2026-02-28",
+    )
+    result = occurrences_between(rule, WINDOW_START, WINDOW_END)
+    # 2026 clamp Feb 28, 2027 clamp Feb 28, 2028 leap Feb 29.
+    assert result == ["2026-02-28", "2027-02-28", "2028-02-29"]
+
+
+def test_yearly_jun_15_interval_2_exact_list() -> None:
+    rule = ScheduleRule(
+        rule_type=RuleType.YEARLY, month=6, day_of_month=15, interval=2,
+        start_date="2026-06-15",
+    )
+    result = occurrences_between(rule, WINDOW_START, WINDOW_END)
+    # y0 2026, y2 2028 (y3 2029 excluded by the 3-year window).
+    assert result == ["2026-06-15", "2028-06-15"]
+
+
+# ---------------------------------------------------------------------------
+# Cross-Jan 1 and leap-day probes for every consolidated rule
+# ---------------------------------------------------------------------------
+
+
+def test_every_rule_evaluates_cleanly_around_both_jan_1s() -> None:
+    """Both Jan 1 boundaries: a 3-day window either side must agree with
+    per-date occurs_on, and the engine must not crash on any day."""
+    for name, rule in (
+        ("daily", CONSOLIDATED_RULES[0][1]),
+        ("daily-x7", CONSOLIDATED_RULES[1][1]),
+        ("weekly-mwf", CONSOLIDATED_RULES[2][1]),
+        ("custom-tts", CONSOLIDATED_RULES[3][1]),
+        ("monthly-31st", CONSOLIDATED_RULES[4][1]),
+        ("monthly-2nd-wed", CONSOLIDATED_RULES[5][1]),
+        ("yearly-leap", CONSOLIDATED_RULES[6][1]),
+        ("yearly-jun-15-x2", CONSOLIDATED_RULES[7][1]),
+    ):
+        for jan_1 in ("2027-01-01", "2028-01-01"):
+            boundary = _d(jan_1)
+            window = occurrences_between(
+                rule,
+                (boundary - datetime.timedelta(days=3)).isoformat(),
+                (boundary + datetime.timedelta(days=3)).isoformat(),
+            )
+            # Ordered and duplicate-free.
+            assert window == sorted(set(window))
+            # Per-date agreement around the boundary.
+            for offset in range(-3, 4):
+                date = boundary + datetime.timedelta(days=offset)
+                fired = occurs_on(rule, date)
+                in_list = date.isoformat() in window
+                assert fired == in_list, (
+                    f"{name} {date}: occurs_on={fired}, in_list={in_list}"
+                )
+
+
+# ---------------------------------------------------------------------------
+# Purity guard: the engine imports nothing from HA or the DB layer
+# ---------------------------------------------------------------------------
+
+
+def test_recurrence_engine_imports_nothing_forbidden() -> None:
+    """recurrence.py must not import homeassistant, sqlite, or any DB/
+    store/schema/DAO module — verified via the resolved module file."""
+    import ast
+    import importlib.util
+    from pathlib import Path
+
+    module_file = Path(
+        importlib.util.find_spec(
+            "custom_components.nestquest.recurrence"
+        ).origin
+    )
+    tree = ast.parse(module_file.read_text())
+    forbidden_leaf = {
+        "db", "schema", "dao_children", "dao_rules", "dao_presence",
+        "dao_instances", "migrations", "store",
+    }
+    for node in ast.walk(tree):
+        if isinstance(node, ast.Import):
+            for alias in node.names:
+                lowered = alias.name.lower()
+                leaf = lowered.split(".")[-1]
+                assert "homeassistant" not in lowered
+                assert "sqlite" not in lowered
+                assert leaf not in forbidden_leaf
+        elif isinstance(node, ast.ImportFrom):
+            module = (node.module or "").lower()
+            assert "homeassistant" not in module
+            assert "sqlite" not in module
+            for alias in node.names:
+                leaf = alias.name.split(".")[-1].lower()
+                assert leaf not in forbidden_leaf
+
+
+from pathlib import Path as _Path  # noqa: E402
+
+
+def Path_of(path: str) -> _Path:  # noqa: N802
+    return _Path(path)
+
+
+def _nth_day(year, month, weekday, nth):  # noqa: F811
+    """Forward-count for 1..5; back-count for -1 (canonical helper)."""
+    if nth == -1:
+        last = datetime.date(year, month, _month_end(year, month))
+        return last.day - ((last.weekday() - weekday) % 7)
+    first = datetime.date(year, month, 1)
+    offset = (weekday - first.weekday()) % 7
+    day = 1 + offset + (nth - 1) * 7
+    if day > _month_end(year, month):
+        return None
+    return day
\ No newline at end of file