core: extract GUI-free logic into bal.core (reminders/checkalive/input_rules); fix save/sign tx RLock pickle by serializing tx; keep invalid heirs in wallet on build; tb1 testnet will-executor addresses; move tests to core modules

bal/core/checkalive.py

@@ -0,0 +1,71 @@
+"""
+bal.core.checkalive
+===================
+
+The "Check Alive" policy: the single reference timestamp (``date_to_check``)
+against which every will-validity check is evaluated, and the BASIC/ADVANCED
+mode rules that decide it.
+
+Pure, GUI-free. The GUI raises :class:`CheckAliveError` to trigger the
+postpone/invalidate flow; the decision that it *should* be raised lives here.
+"""
+
+from datetime import datetime
+from typing import Any
+
+from .plugin_base import BalTimestamp
+
+
+class CheckAliveError(Exception):
+    """Raised when the "check alive" date is in the past."""
+
+    def __init__(self, timestamp_to_check):
+        self.timestamp_to_check = timestamp_to_check
+
+    def __str__(self):
+        return "Check alive expired please update it: {}".format(
+            datetime.fromtimestamp(self.timestamp_to_check).isoformat()
+        )
+
+
+def resolve_date_to_check(
+    is_basic_mode: bool, will_settings: Any, now: float | None = None
+) -> float:
+    """Return the reference timestamp for every will-validity check.
+
+    ``date_to_check`` is the single reference timestamp that EVERY downstream
+    check reads: the build filter, the heir count, ``check_will_expired``,
+    ``check_amounts`` and the locktime-vs-threshold guard.
+
+    * BASIC mode: the Check Alive is hidden and NOT editable, so it must never
+      govern those checks. ``date_to_check`` is set to *now*: every check is
+      evaluated against the current moment (the Check Alive effectively does not
+      exist) while the delivery locktime is still fully enforced.
+    * ADVANCED mode: the user-controlled stored threshold is used as-is.
+
+    Args:
+        is_basic_mode: ``True`` for the SIMPLE / BASIC user type.
+        will_settings: the per-wallet settings dict (``"threshold"`` key).
+        now: overridable clock for tests; defaults to ``datetime.now()``.
+
+    Returns:
+        The reference timestamp (float, UNIX seconds).
+    """
+    if is_basic_mode:
+        return (now if now is not None else datetime.now().timestamp())
+    return BalTimestamp(will_settings["threshold"]).to_timestamp()
+
+
+def check_alive_expired(
+    is_basic_mode: bool, date_to_check: float, now: float | None = None
+) -> bool:
+    """True when the Check Alive guard should fire (``CheckAliveError``).
+
+    Only ADVANCED mode can be "expired": in BASIC mode the Check Alive is inert
+    by construction, so a passed check-alive date must never force a postpone or
+    rewrite of the will.
+    """
+    if is_basic_mode:
+        return False
+    current = now if now is not None else datetime.now().timestamp()
+    return date_to_check < current

bal/core/heirs.py

@@ -630,7 +630,19 @@ class Heirs(dict, Logger):
     def buildTransactions(
         self, bal_plugin, wallet, tx_fees=None, utxos=None, from_locktime=0
     ):
-        Heirs._validate(self)
+        _before = list(self.keys())
+        Heirs._validate(self, persist=False)
+        _removed = [k for k in _before if k not in self]
+        if _removed:
+            # The build skips invalid heirs, but they are only dropped in memory
+            # (persist=False): the wallet still keeps them, so the user can fix
+            # or remove them deliberately instead of losing them silently.
+            _logger.warning(
+                "buildTransactions: skipped %d invalid heir(s) (kept in wallet, "
+                "not removed): %s",
+                len(_removed),
+                ", ".join(_removed),
+            )
         if len(self) <= 0:
             _logger.info("while building transactions there was no heirs")
             return
@@ -877,16 +889,22 @@ class Heirs(dict, Logger):
         return (address, amount, locktime)
 
     @staticmethod
-    def _validate(data, timestamp_to_check=False):
+    def _validate(data, timestamp_to_check=False, persist=True):
 
         for k, v in list(data.items()):
             if k == "heirs":
-                return Heirs._validate(v, timestamp_to_check)
+                return Heirs._validate(v, timestamp_to_check, persist)
             try:
                 Heirs.validate_heir(k, v, timestamp_to_check)
             except Exception as e:
                 _logger.info(f"exception heir removed {e}")
+                if persist:
                     data.pop(k)
+                else:
+                    # Drop the invalid heir in memory only, so the overridden
+                    # Heirs.pop (which calls save()) is not triggered: a build
+                    # must not silently delete heirs from the wallet.
+                    dict.pop(data, k)
         return data
 
 

bal/core/input_rules.py

@@ -0,0 +1,193 @@
+"""
+bal.core.input_rules
+====================
+
+Pure, GUI-free rules for the plugin's text-input widgets: locktime bounds and
+acceptance, the RAW locktime sanitisation ("30d"/"1y"), and the percentage-or-
+amount field normalisation.
+
+These used to live inside the Qt widget classes in ``bal.gui.qt.widgets``.
+Keeping them here makes them testable without Qt and lets any GUI front-end
+reuse the exact same parsing rules.
+"""
+
+from datetime import datetime
+from decimal import Decimal
+from typing import Any, Optional, Tuple, Union
+
+from electrum.bitcoin import NLOCKTIME_BLOCKHEIGHT_MAX, NLOCKTIME_MAX, NLOCKTIME_MIN
+
+__all__ = [
+    "NLOCKTIME_BLOCKHEIGHT_MAX",
+    "NLOCKTIME_MAX",
+    "NLOCKTIME_MIN",
+    "LockTimeEditor",
+    "normalize_locktime_raw_text",
+    "normalize_perc_amount_text",
+    "parse_perc_amount",
+    "replace_dy_suffixes",
+]
+
+
+class LockTimeEditor:
+    """Acceptance bounds shared by the RAW and Date locktime editors.
+
+    A Qt widget mixin historically; the pure parts (bounds and acceptance test)
+    live here so they can be tested and reused without Qt. Widget subclasses
+    override ``min_allowed_value``/``max_allowed_value`` to tighten the bounds.
+    """
+
+    min_allowed_value = NLOCKTIME_MIN
+    max_allowed_value = NLOCKTIME_MAX
+    alarm = None
+
+    def get_value(self) -> Optional[int]:
+        raise NotImplementedError()
+
+    def set_value(self, x: Any, force=True) -> None:
+        raise NotImplementedError()
+
+    @classmethod
+    def is_acceptable_locktime(cls, x: Any) -> bool:
+        """True when ``x`` (string or int) is within the allowed locktime bounds.
+
+        An empty/falsy value is accepted (the field is not yet filled in).
+        """
+        if not x:  # e.g. empty string
+            return True
+        try:
+            x = int(x)
+        except Exception as _e:
+            return False
+        return cls.min_allowed_value <= x <= cls.max_allowed_value
+
+    @staticmethod
+    def get_max_allowed_timestamp() -> int:
+        """Highest locktime timestamp accepted on this platform.
+
+        On 32-bit ``time_t`` Windows builds ``datetime.fromtimestamp`` overflows
+        past 2038, so the ceiling is clamped to INT32_MAX (see #6170).
+        """
+        ts = NLOCKTIME_MAX
+        # Test if this value is within the valid timestamp limits (which is
+        # platform-dependent).  see #6170
+        try:
+            datetime.fromtimestamp(ts)
+        except (OSError, OverflowError):
+            ts = 2**31 - 1  # INT32_MAX
+            datetime.fromtimestamp(ts)  # test if raises
+        return ts
+
+
+def replace_dy_suffixes(text: str) -> str:
+    """Strip the relative-time suffixes (d/y) from ``text``.
+
+    Only days ("d") and years ("y") are supported. The block-height suffix
+    ("b") was removed (A1): locktimes are always timestamps now.
+    """
+    return str(text).replace("d", "").replace("y", "")
+
+
+def _checkbdy(s: str, pos: int, appendix: str) -> Tuple[int, str]:
+    """Keep a ``d``/``y`` suffix typed right after an existing suffix.
+
+    When the character just before ``pos`` equals ``appendix``, the text is
+    re-normalised so only one suffix remains.
+    """
+    try:
+        charpos = pos - 1
+        charpos = max(0, charpos)
+        charpos = min(len(s) - 1, charpos)
+        if appendix == s[charpos]:
+            s = replace_dy_suffixes(s) + appendix
+            pos = charpos
+    except Exception:
+        pass
+    return pos, s
+
+
+def normalize_locktime_raw_text(
+    text: str, pos: int
+) -> Tuple[str, bool, bool, int]:
+    """Sanitise the RAW locktime field text.
+
+    Only digits plus the day ("d") and year ("y") suffixes are kept; the block
+    suffix ("b") is removed (A1). Exactly one ``d``/``y`` suffix survives.
+
+    Args:
+        text: the raw field text.
+        pos: the cursor position within ``text``.
+
+    Returns:
+        ``(clean, isdays, isyears, new_pos)`` where ``clean`` is the sanitised
+        text and ``new_pos`` the adjusted cursor position.
+    """
+    text = text.strip()
+    chars = "0123456789dy"
+    pos = len("".join([i for i in text[:pos] if i in chars]))
+    s = "".join([i for i in text if i in chars])
+    isdays = False
+    isyears = False
+
+    pos, s = _checkbdy(s, pos, "d")
+    pos, s = _checkbdy(s, pos, "y")
+
+    if "d" in s:
+        isdays = True
+    if "y" in s:
+        isyears = True
+
+    if isdays:
+        s = replace_dy_suffixes(s) + "d"
+    if isyears:
+        s = replace_dy_suffixes(s) + "y"
+    return s, isdays, isyears, pos
+
+
+def normalize_perc_amount_text(text: str, decimal_point: str) -> Tuple[str, bool]:
+    """Sanitise the amount-or-percentage field text.
+
+    Keeps digits, ``%`` and the decimal point; a trailing ``%`` marks the value
+    as a percentage (``is_perc``). At most 8 decimal digits after the point.
+
+    Args:
+        text: the raw field text.
+        decimal_point: the decimal separator character (``electrum`` uses
+            ``DECIMAL_POINT``, locale dependent).
+
+    Returns:
+        ``(clean, is_perc)``.
+    """
+    text = text.strip()
+    chars = "0123456789%"
+    chars += decimal_point
+
+    s = "".join([i for i in text if i in chars])
+
+    if "%" in s:
+        is_perc = True
+        s = s.replace("%", "")
+    else:
+        is_perc = False
+
+    if decimal_point in s:
+        p = s.find(decimal_point)
+        s = s.replace(decimal_point, "")
+        s = s[:p] + decimal_point + s[p : p + 8]
+    if is_perc:
+        s += "%"
+
+    return s, is_perc
+
+
+def parse_perc_amount(text: str, decimal_point: str) -> Union[None, Decimal, int]:
+    """Parse an amount-or-percentage field text into a numeric value.
+
+    Returns ``None`` when the text cannot be parsed.
+    """
+    try:
+        text = text.replace(decimal_point, ".")
+        text = text.replace("%", "")
+        return Decimal(text)
+    except Exception:
+        return None

bal/core/plugin_base.py

@@ -306,7 +306,10 @@ class BalPlugin(BasePlugin):
             config, "bal_event_summary", "BAL -Will execution of $wallet_name"
         )
 
-        # Default will-executor servers, keyed by network.
+        # Default will-executor servers, keyed by network.  These addresses are
+        # the ones currently reported by each server's <chain>/info endpoint and
+        # are refreshed again on ping; testnet/testnet4 must NOT be regtest
+        # (bcrt1...) addresses, which are invalid on those networks.
         self.WILLEXECUTORS = BalConfig(
             config,
             "bal_willexecutors",
@@ -325,7 +328,7 @@ class BalPlugin(BasePlugin):
                         "base_fee": 100000,
                         "status": "New",
                         "info": "Bitcoin After Life Will Executor",
-                        "address": "bcrt1qa5cntu4hgadw8zd3n6sq2nzjy34sxdtd9u0gp7",
+                        "address": "tb1qp5tmrvtm6dmz23mzkf55n5d53xh39wt0gwpp5m",
                         "selected": True,
                     }
                 },
@@ -334,7 +337,7 @@ class BalPlugin(BasePlugin):
                         "base_fee": 100000,
                         "status": "New",
                         "info": "Bitcoin After Life Will Executor",
-                        "address": "bcrt1qa5cntu4hgadw8zd3n6sq2nzjy34sxdtd9u0gp7",
+                        "address": "tb1qfj5ewmczg8ck2z0eeff6uysdrxd4qdy2ltrx5a",
                         "selected": True,
                     }
                 },

bal/core/reminders.py

@@ -0,0 +1,228 @@
+"""
+bal.core.reminders
+==================
+
+Pure, GUI-free logic for the dead-man's-switch calendar reminders: choosing the
+reminder offsets (BASIC vs ADVANCED modes) and rendering them as an RFC-5545
+iCalendar (.ics) document.
+
+Everything in this module is stdlib-only, so it can be imported and tested
+without Electrum or Qt (e.g. in the lint venv).
+"""
+
+import os
+import tempfile
+from datetime import datetime, timedelta, timezone
+from typing import Optional
+
+
+def compute_reminder_offsets(days, count):
+    """Return the reminder offsets (in days BEFORE the deadline) for an .ics event.
+
+    Group D / D1. The reminders are spread uniformly across the check-alive
+    period and always fall *before* the delivery deadline, i.e. every returned
+    offset is ``>= 1`` (a reminder exactly on the deadline would be useless).
+
+    Rules:
+        * ``count`` is the requested number of reminders (the settings dialog
+          caps it at 5, default 3).
+        * at most ONE reminder per available day: the effective number is
+          ``min(count, days)``;
+        * with ``days`` available days, offsets are chosen as evenly spaced
+          points inside ``[1, days]`` (1 = the day before the deadline, ``days``
+          = the first day of the period), de-duplicated and returned sorted
+          descending (earliest reminder first).
+
+    Args:
+        days: number of whole days between check-alive and the deadline.
+        count: requested number of reminders.
+
+    Returns:
+        A list of integer day-offsets (each ``>= 1``), e.g. ``[22, 15, 8]`` for
+        ``days=30, count=3``. Empty if there is no room for any reminder.
+    """
+    # No room for any reminder (deadline today or already passed).
+    if days < 1 or count < 1:
+        return []
+
+    # Never more reminders than available days (one per day at most).
+    effective = min(int(count), int(days))
+
+    # A single reminder: put it one day before the deadline.
+    if effective == 1:
+        return [1]
+
+    # Spread "effective" points evenly inside [1, days]. Using i/(effective-1)
+    # for i in 0..effective-1 gives fractions 0..1; map them onto [1, days].
+    # This places the first reminder at the start of the period (offset ~days)
+    # and the last one one day before the deadline (offset 1).
+    offsets = set()
+    for i in range(effective):
+        frac = i / (effective - 1)  # 0.0 .. 1.0
+        # offset = days at frac 0 (start), 1 at frac 1 (just before deadline).
+        offset = round(days - frac * (days - 1))
+        offset = max(1, min(days, offset))
+        offsets.add(offset)
+
+    # Sorted descending: earliest reminder (largest offset) first.
+    return sorted(offsets, reverse=True)
+
+
+# Fixed reminder offsets (in days BEFORE the delivery date) used in BASIC mode.
+# In BASIC the check-alive parameter is hidden/unmanaged, so reminders cannot be
+# spread over it; instead the owner asked for three fixed reminders: 30, 10 and
+# 1 day before the inheritance delivery date.
+BASIC_REMINDER_OFFSETS = (30, 10, 1)
+
+
+def basic_reminder_offsets(days_to_deadline):
+    """Return the BASIC-mode reminder offsets that still fall in the future.
+
+    BASIC mode uses the fixed offsets in ``BASIC_REMINDER_OFFSETS`` (30, 10 and
+    1 day before the delivery date). Any offset that would land in the past is
+    dropped, because a reminder before "today" is useless: if the delivery date
+    is only ``days_to_deadline`` days away, only the offsets that are ``<=
+    days_to_deadline`` are kept.
+
+    Args:
+        days_to_deadline: whole days from now until the delivery date.
+
+    Returns:
+        A list of integer day-offsets (each ``>= 1``), sorted as in
+        ``BASIC_REMINDER_OFFSETS`` (descending: earliest reminder first). Empty
+        when the delivery date is less than one day away.
+    """
+    horizon = max(int(days_to_deadline), 0)
+    return [off for off in BASIC_REMINDER_OFFSETS if 1 <= off <= horizon]
+
+
+def format_time(time) -> str:
+    """Render a datetime as an RFC-5545 UTC timestamp (``YYYYMMDDTHHMMSSZ``)."""
+    return time.astimezone(timezone.utc).strftime("%Y%m%dT%H%M%SZ")
+
+
+def fold_ical_line(line: str, limit: int = 75) -> str:
+    """Fold a line to at most ``limit`` bytes per RFC-5545, without splitting
+    multi-byte UTF-8 characters. Continuation lines start with a space."""
+    encoded = line.encode("utf-8")
+    parts = []
+    while len(encoded) > limit:
+        # cut without splitting a UTF-8 continuation byte
+        cut = limit
+        while (encoded[cut] & 0xC0) == 0x80:  # byte de continuazione UTF-8
+            cut -= 1
+        parts.append(encoded[:cut].decode("utf-8"))
+        encoded = encoded[cut:]
+    parts.append(encoded.decode("utf-8"))
+    return "\r\n ".join(parts)
+
+
+def ical_escape(text: str) -> str:
+    """Escape a string per RFC-5545: backslash, semicolon, comma, newlines."""
+    text = (
+        text.replace("\\", "\\\\")
+        .replace(";", "\\;")
+        .replace(",", "\\,")
+    )
+    return "\r\n".join(fold_ical_line(line) for line in text.split("\r\n"))
+
+
+def write_temp_ics(content: str) -> str:
+    """Write ``content`` to a temporary ``.ics`` file and return its path."""
+    fd, path = tempfile.mkstemp(prefix="event_", suffix=".ics")
+    with os.fdopen(fd, "wb") as f:
+        f.write(content.encode("utf-8"))
+    return path
+
+
+def build_ics_reminders(
+    *,
+    locktime: datetime,
+    basic_mode: bool,
+    description: str,
+    summary: str,
+    wallet_name: str,
+    heirs_details: str,
+    version: str,
+    num_reminders: int = 3,
+    now: Optional[datetime] = None,
+    threshold: Optional[datetime] = None,
+) -> Optional[str]:
+    """Build the ``.ics`` content with one VEVENT per reminder date.
+
+    Group D / D1 (revised): N *separate* VEVENTs, one per reminder date, so the
+    user sees several distinct appointments in their calendar. The reminder
+    offsets come from :func:`basic_reminder_offsets` (BASIC mode) or
+    :func:`compute_reminder_offsets` (ADVANCED mode, spread over the check-alive
+    period).
+
+    Args:
+        locktime: the delivery deadline (datetime).
+        basic_mode: use the fixed BASIC offsets instead of spreading over the
+            check-alive period.
+        description: raw EVENT_DESCRIPTION template; ``$wallet_name`` and
+            ``$heirs_complete`` placeholders are substituted and escaped.
+        summary: raw EVENT_SUMMARY template; ``$wallet_name`` is substituted.
+        wallet_name: label used in the UID and template substitutions.
+        heirs_details: pre-formatted heir list injected into ``description``.
+        version: plugin version, embedded in the PRODID line.
+        num_reminders: requested reminder count (ADVANCED mode only).
+        now: "today" reference; defaults to ``datetime.now()``.
+        threshold: check-alive date (ADVANCED mode only; required there).
+
+    Returns:
+        The ``.ics`` content string, or ``None`` when no reminder falls in the
+        future (the delivery date is too close or already passed) so the caller
+        can show a warning instead of producing an empty-looking file.
+    """
+    now = now if now is not None else datetime.now()
+
+    if basic_mode:
+        days_to_deadline = (locktime - now).days
+        offsets = basic_reminder_offsets(days_to_deadline)
+    else:
+        if threshold is None:
+            raise ValueError("threshold is required in ADVANCED mode")
+        days = (locktime - threshold).days
+        offsets = compute_reminder_offsets(days, num_reminders)
+
+    # ToDo #2: no future reminder means there are no events to write. Return
+    # None so the caller shows a clear warning instead of an empty .ics file.
+    if not offsets:
+        return None
+
+    event_description = ical_escape(
+        f"{description}"
+        .replace("$wallet_name", str(wallet_name))
+        .replace("$heirs_complete", heirs_details)
+    )
+    summary_base = f"{summary}".replace("$wallet_name", str(wallet_name))
+
+    lines = [
+        "BEGIN:VCALENDAR",
+        "VERSION:2.0",
+        f"PRODID:-//Bitcoin After Life//Electrum Plugin/{version}",
+    ]
+
+    # One separate VEVENT per reminder offset (its own date in the calendar).
+    total = len(offsets)
+    for idx, offset in enumerate(offsets, start=1):
+        # The visible date of this event: "offset" days before the deadline.
+        event_dt = format_time(locktime - timedelta(days=offset))
+        # Suffix the summary so the N events are easy to tell apart.
+        event_summary = ical_escape(f"{summary_base} (reminder {idx}/{total})")
+        lines.extend([
+            "BEGIN:VEVENT",
+            # Offset in the UID keeps each event unique (no merging).
+            f"UID:bal-{str(wallet_name)}-{offset}d",
+            f"DTSTAMP:{format_time(now)}",
+            f"DTSTART:{event_dt}",
+            f"DTEND:{event_dt}",
+            f"SUMMARY:{event_summary}",
+            f"DESCRIPTION:{event_description}",
+            "END:VEVENT",
+        ])
+
+    lines.append("END:VCALENDAR")
+    lines = [s.rstrip("\r\n") for s in lines]
+    return "\r\n".join(lines) + "\r\n"

bal/gui/qt/calendar.py

@@ -7,11 +7,16 @@ iCalendar (.ics) generation and "open with default calendar app" helper.
 When a will is built, the plugin can create a calendar event reminding the user
 to "check in" before the locktime expires.  This module turns the event data
 into an RFC-5545 .ics file and opens it with the OS default application.
+
+The pure RFC-5545 logic (offsets, escaping, folding, the unified .ics builder,
+``write_temp_ics``) lives in :mod:`bal.core.reminders`; this module keeps only
+the Qt button and the OS/subprocess glue.
 """
 
 from PyQt6.QtGui import QAction
 from PyQt6.QtWidgets import QToolButton
 
+from ...core.reminders import write_temp_ics
 from .common import *
 from .common import _, _logger  # underscore names are not re-exported by "import *"
 
@@ -57,7 +62,7 @@ class BalCalendarButton(QToolButton):
         try:
             content = self._ics_provider()
             if content:
-                self._calendar_temp_path = BalCalendar.write_temp_ics(content)
+                self._calendar_temp_path = write_temp_ics(content)
             else:
                 self._calendar_temp_path = None
                 self._bal_window.show_warning(
@@ -149,13 +154,6 @@ class BalCalendarButton(QToolButton):
 
 
 class BalCalendar:
-    @staticmethod
-    def write_temp_ics(content):
-        fd, path = tempfile.mkstemp(prefix="event_", suffix=".ics")
-        with os.fdopen(fd, "wb") as f:
-            f.write(content.encode("utf-8"))
-        return path
-
     @staticmethod
     def open_with_default_app(calendar_app, path):
         _logger.debug("opening calendar app")
@@ -184,37 +182,3 @@ class BalCalendar:
         if os.path.isdir(desktop):
             return desktop
         return home
-
-
-    @staticmethod
-    def format_time(time):
-        return time.astimezone(timezone.utc).strftime("%Y%m%dT%H%M%SZ")
-        #return time.astimezone(timezone.utc).strftime("%Y%m%d")
-
-    @staticmethod
-    def ical_escape(text: str) -> str:
-        # escape per RFC5545: backslash, ; , newlines
-        text = (
-            text.replace("\\", "\\\\")
-            .replace(";", "\\;")
-            .replace(",", "\\,")
-        )
-        return "\r\n".join(
-            BalCalendar.fold_ical_line(line)
-            for line in text.split("\r\n")
-        )
-
-    @staticmethod
-    def fold_ical_line(line: str, limit: int = 75) -> str:
-        # ritorna linee separate da CRLF e folding con spazio iniziale sulle righe successive
-        encoded = line.encode("utf-8")
-        parts = []
-        while len(encoded) > limit:
-            # taglia senza spezzare byte UTF-8
-            cut = limit
-            while (encoded[cut] & 0xC0) == 0x80:  # byte di continuazione UTF-8
-                cut -= 1
-            parts.append(encoded[:cut].decode("utf-8"))
-            encoded = encoded[cut:]
-        parts.append(encoded.decode("utf-8"))
-        return "\r\n ".join(parts)

bal/gui/qt/common.py

@@ -12,7 +12,7 @@ hosts a few GUI helpers that do not deserve a module of their own:
     * :func:`add_widget`      - add a labelled widget (plus optional help) to a grid.
     * :func:`log_error`       - format an exception traceback for a dialog.
     * :func:`export_meta_gui` - export plugin metadata to a JSON file.
-    * :class:`CheckAliveError`- raised when the "check alive" date is in the past.
+      (:class:`CheckAliveError` now lives in ``bal.core.checkalive``.)
 """
 
 import copy
@@ -181,18 +181,6 @@ def add_widget(grid, label, widget, row, help_):
 
 
 
-class CheckAliveError(Exception):
-    def __init__(self, timestamp_to_check):
-        self.timestamp_to_check = timestamp_to_check
-
-    def __str__(self):
-        return "Check alive expired please update it: {}".format(
-            datetime.fromtimestamp(self.timestamp_to_check).isoformat()
-        )
-
-
-
-
 def log_error(exec_info, window=None):
     """Log an error and optionally show it.
 

bal/gui/qt/dialogs.py

@@ -19,14 +19,14 @@ use them (see ``lists`` imports below).
 
 from typing import TYPE_CHECKING
 
-from .calendar import BalCalendar, BalCalendarButton
+from ...core.checkalive import CheckAliveError
+from ...core.reminders import build_ics_reminders
+from .calendar import BalCalendarButton
 from .common import *
 from .common import _, _logger  # underscore names are not re-exported by "import *"
 from .widgets import (
     WillSettingsWidget,
     WillWidget,
-    basic_reminder_offsets,
-    compute_reminder_offsets,
 )
 
 if TYPE_CHECKING:
@@ -1598,7 +1598,7 @@ class BalBuildWillDialog(BalDialog):
 
     def _ics_provider(self):
         """Return the .ics content for the current will data."""
-        from datetime import datetime, timedelta
+        from datetime import datetime
 
         try:
             locktime_ts = Util.parse_locktime_string(
@@ -1606,22 +1606,25 @@ class BalBuildWillDialog(BalDialog):
             )
             locktime = datetime.fromtimestamp(locktime_ts)
 
-            if self.bal_window.bal_plugin.is_basic_mode():
+            basic_mode = self.bal_window.bal_plugin.is_basic_mode()
-                days_to_deadline = (locktime - datetime.now()).days
+            if basic_mode:
-                offsets = basic_reminder_offsets(days_to_deadline)
+                raw_description = self.bal_window.bal_plugin.EVENT_DESCRIPTION.default
+                raw_summary = self.bal_window.bal_plugin.EVENT_SUMMARY.default
+                threshold = None
+                num_reminders = 3
             else:
                 threshold_ts = BalTimestamp(
                     self.bal_window.will_settings["threshold"]
                 ).to_timestamp()
                 threshold = datetime.fromtimestamp(threshold_ts)
-                days = (locktime - threshold).days
+                raw_description = self.bal_window.bal_plugin.EVENT_DESCRIPTION.get()
+                raw_summary = self.bal_window.bal_plugin.EVENT_SUMMARY.get()
                 try:
-                    count = int(self.bal_window.bal_plugin.NUM_REMINDERS.get())
+                    num_reminders = int(
+                        self.bal_window.bal_plugin.NUM_REMINDERS.get()
+                    )
                 except Exception:
-                    count = 3
+                    num_reminders = 3
-                offsets = compute_reminder_offsets(days, count)
-
-            now = BalCalendar.format_time(datetime.now())
 
             heirs_details = "\r\n".join(
                 f" {heir} - {self.bal_window.heirs[heir][0]}, "
@@ -1629,56 +1632,21 @@ class BalBuildWillDialog(BalDialog):
                 for heir in self.bal_window.heirs
             )
 
-            if self.bal_window.bal_plugin.is_basic_mode():
+            # ToDo #2: when no reminder falls in the future (the delivery date is
-                raw_description = self.bal_window.bal_plugin.EVENT_DESCRIPTION.default
+            # too close or already passed), build_ics_reminders returns None so
-                raw_summary = self.bal_window.bal_plugin.EVENT_SUMMARY.default
+            # the caller shows a clear warning instead of producing an empty,
-            else:
+            # seemingly-broken .ics file.
-                raw_description = self.bal_window.bal_plugin.EVENT_DESCRIPTION.get()
+            return build_ics_reminders(
-                raw_summary = self.bal_window.bal_plugin.EVENT_SUMMARY.get()
+                locktime=locktime,
-
+                basic_mode=basic_mode,
-            event_description = BalCalendar.ical_escape(
+                description=raw_description,
-                f"{raw_description}"
+                summary=raw_summary,
-                .replace("$wallet_name", str(self.bal_window.wallet))
+                wallet_name=str(self.bal_window.wallet),
-                .replace("$heirs_complete", heirs_details)
+                heirs_details=heirs_details,
+                version=self.bal_window.bal_plugin.version,
+                num_reminders=num_reminders,
+                threshold=threshold,
             )
-            summary_base = (
-                f"{raw_summary}"
-                .replace("$wallet_name", str(self.bal_window.wallet))
-            )
-
-            lines = [
-                "BEGIN:VCALENDAR",
-                "VERSION:2.0",
-                "PRODID:-//Bitcoin After Life//Electrum Plugin/"
-                f"{self.bal_window.bal_plugin.version}",
-            ]
-
-            total = len(offsets)
-            # ToDo #2: if no reminder falls in the future (the delivery date is
-            # too close or already passed), there are no events to write.
-            # Return None so the caller shows a clear warning instead of
-            # producing an empty, seemingly-broken .ics file.
-            if total == 0:
-                return None
-            for idx, offset in enumerate(offsets, start=1):
-                event_dt = BalCalendar.format_time(locktime - timedelta(days=offset))
-                summary = BalCalendar.ical_escape(
-                    f"{summary_base} (reminder {idx}/{total})"
-                )
-                lines.extend([
-                    "BEGIN:VEVENT",
-                    f"UID:bal-{str(self.bal_window.wallet)}-{offset}d",
-                    f"DTSTAMP:{now}",
-                    f"DTSTART:{event_dt}",
-                    f"DTEND:{event_dt}",
-                    f"SUMMARY:{summary}",
-                    f"DESCRIPTION:{event_description}",
-                    "END:VEVENT",
-                ])
-
-            lines.append("END:VCALENDAR")
-            lines = [s.rstrip("\r\n") for s in lines]
-            return "\r\n".join(lines) + "\r\n"
         except Exception as e:
             _logger.error(f"failed to generate .ics: {e}")
             return None
@@ -1706,7 +1674,12 @@ class BalBuildWillDialog(BalDialog):
             try:
                 if txs := self.bal_window.sign_transactions(password):
                     for txid, tx in txs.items():
-                        self.bal_window.willitems[txid].tx = copy.deepcopy(tx)
+                        # Re-parse instead of deepcopy (the signed tx can carry
+                        # wallet-derived input info holding a threading.RLock,
+                        # which copy.deepcopy cannot pickle).
+                        self.bal_window.willitems[txid].tx = Will.get_tx_from_any(
+                            str(tx)
+                        )
                     self.bal_window.save_willitems()
                     self.msg_set_signing(self.msg_ok())
             except Exception as e:

bal/gui/qt/widgets.py

@@ -20,6 +20,13 @@ Contents:
 
 from typing import TYPE_CHECKING
 
+from ...core.input_rules import (
+    LockTimeEditor,
+    normalize_locktime_raw_text,
+    normalize_perc_amount_text,
+    parse_perc_amount,
+)
+from ...core.reminders import build_ics_reminders, write_temp_ics
 from .calendar import BalCalendar, BalCalendarButton
 from .common import *
 from .common import _, _logger  # underscore names are not re-exported by "import *"
@@ -28,86 +35,6 @@ if TYPE_CHECKING:
     from .window import BalWindow
 
 
-def compute_reminder_offsets(days, count):
-    """Return the reminder offsets (in days BEFORE the deadline) for an .ics event.
-
-    Group D / D1. The reminders are spread uniformly across the check-alive
-    period and always fall *before* the delivery deadline, i.e. every returned
-    offset is ``>= 1`` (a reminder exactly on the deadline would be useless).
-
-    Rules:
-        * ``count`` is the requested number of reminders (the settings dialog
-          caps it at 5, default 3).
-        * at most ONE reminder per available day: the effective number is
-          ``min(count, days)``;
-        * with ``days`` available days, offsets are chosen as evenly spaced
-          points inside ``[1, days]`` (1 = the day before the deadline, ``days``
-          = the first day of the period), de-duplicated and returned sorted
-          descending (earliest reminder first).
-
-    Args:
-        days: number of whole days between check-alive and the deadline.
-        count: requested number of reminders.
-
-    Returns:
-        A list of integer day-offsets (each ``>= 1``), e.g. ``[22, 15, 8]`` for
-        ``days=30, count=3``. Empty if there is no room for any reminder.
-    """
-    # No room for any reminder (deadline today or already passed).
-    if days < 1 or count < 1:
-        return []
-
-    # Never more reminders than available days (one per day at most).
-    effective = min(int(count), int(days))
-
-    # A single reminder: put it one day before the deadline.
-    if effective == 1:
-        return [1]
-
-    # Spread "effective" points evenly inside [1, days]. Using i/(effective-1)
-    # for i in 0..effective-1 gives fractions 0..1; map them onto [1, days].
-    # This places the first reminder at the start of the period (offset ~days)
-    # and the last one one day before the deadline (offset 1).
-    offsets = set()
-    for i in range(effective):
-        frac = i / (effective - 1)  # 0.0 .. 1.0
-        # offset = days at frac 0 (start), 1 at frac 1 (just before deadline).
-        offset = round(days - frac * (days - 1))
-        offset = max(1, min(days, offset))
-        offsets.add(offset)
-
-    # Sorted descending: earliest reminder (largest offset) first.
-    return sorted(offsets, reverse=True)
-
-
-# Fixed reminder offsets (in days BEFORE the delivery date) used in BASIC mode.
-# In BASIC the check-alive parameter is hidden/unmanaged, so reminders cannot be
-# spread over it; instead the owner asked for three fixed reminders: 30, 10 and
-# 1 day before the inheritance delivery date.
-BASIC_REMINDER_OFFSETS = (30, 10, 1)
-
-
-def basic_reminder_offsets(days_to_deadline):
-    """Return the BASIC-mode reminder offsets that still fall in the future.
-
-    BASIC mode uses the fixed offsets in ``BASIC_REMINDER_OFFSETS`` (30, 10 and
-    1 day before the delivery date). Any offset that would land in the past is
-    dropped, because a reminder before "today" is useless: if the delivery date
-    is only ``days_to_deadline`` days away, only the offsets that are ``<=
-    days_to_deadline`` are kept.
-
-    Args:
-        days_to_deadline: whole days from now until the delivery date.
-
-    Returns:
-        A list of integer day-offsets (each ``>= 1``), sorted as in
-        ``BASIC_REMINDER_OFFSETS`` (descending: earliest reminder first). Empty
-        when the delivery date is less than one day away.
-    """
-    horizon = max(int(days_to_deadline), 0)
-    return [off for off in BASIC_REMINDER_OFFSETS if 1 <= off <= horizon]
-
-
 class ClickableLabel(QLabel):
     doubleClicked = pyqtSignal()
 
@@ -219,39 +146,12 @@ class BalTxFeesWidget(QWidget):
 
 
 
-class _LockTimeEditor:
+class _LockTimeEditor(LockTimeEditor):
-    min_allowed_value = NLOCKTIME_MIN
+    """Qt-side locktime editor base.
-    max_allowed_value = NLOCKTIME_MAX
-    alarm = None
-
-    def get_value(self) -> Optional[int]:
-        raise NotImplementedError()
-
-    def set_value(self, x: Any, force=True) -> None:
-        raise NotImplementedError()
-
-    @classmethod
-    def is_acceptable_locktime(cls, x: Any) -> bool:
-        if not x:  # e.g. empty string
-            return True
-        try:
-            x = int(x)
-        except Exception as _e:
-            return False
-        return cls.min_allowed_value <= x <= cls.max_allowed_value
-
-    @staticmethod
-    def get_max_allowed_timestamp() -> int:
-        ts = NLOCKTIME_MAX
-        # Test if this value is within the valid timestamp limits (which is platform-dependent).
-        # see #6170
-        try:
-            datetime.fromtimestamp(ts)
-        except (OSError, OverflowError):
-            ts = 2**31 - 1  # INT32_MAX
-            datetime.fromtimestamp(ts)  # test if raises
-        return ts
 
+    The pure acceptance bounds and helpers live in ``bal.core.input_rules``;
+    this is just the mixin that lets Qt widgets reuse them.
+    """
 
 
 class BalTimeEditWidget(QWidget, _LockTimeEditor):
@@ -572,51 +472,16 @@ class LockTimeRawEdit(QLineEdit, _LockTimeEditor):
         self.isyears = False
         self.time_edit = time_edit
 
-    @staticmethod
-    def replace_str(text):
-        """Strip the relative-time suffixes (d/y) from the text.
-
-        Only days ("d") and years ("y") are supported. The block-height
-        suffix ("b") was removed (A1): locktimes are always timestamps now.
-        """
-        return str(text).replace("d", "").replace("y", "")
-
-    def checkbdy(self, s, pos, appendix):
-        try:
-            charpos = pos - 1
-            charpos = max(0, charpos)
-            charpos = min(len(s) - 1, charpos)
-            if appendix == s[charpos]:
-                s = self.replace_str(s) + appendix
-                pos = charpos
-        except Exception:
-            pass
-        return pos, s
-
     def numbify(self):
         # Only digits plus the day ("d") and year ("y") suffixes are accepted.
         # The block-height suffix ("b") was removed (A1): locktimes are always
         # UNIX timestamps now, so block-relative input is no longer allowed.
+        # The sanitisation itself lives in bal.core.input_rules.
         text = self.text().strip()
-        chars = "0123456789dy"
         pos = self.cursorPosition()
-        pos = len("".join([i for i in text[:pos] if i in chars]))
+        s, isdays, isyears, pos = normalize_locktime_raw_text(text, pos)
-        s = "".join([i for i in text if i in chars])
+        self.isdays = isdays
-        self.isdays = False
+        self.isyears = isyears
-        self.isyears = False
-
-        pos, s = self.checkbdy(s, pos, "d")
-        pos, s = self.checkbdy(s, pos, "y")
-
-        if "d" in s:
-            self.isdays = True
-        if "y" in s:
-            self.isyears = True
-
-        if self.isdays:
-            s = self.replace_str(s) + "d"
-        if self.isyears:
-            s = self.replace_str(s) + "y"
         self.blockSignals(True)
         self.setText(s)
         self.blockSignals(False)
@@ -1073,11 +938,12 @@ class WillSettingsWidget(QWidget):
         sees several distinct appointments in their calendar.
 
         The number of events is read from the NUM_REMINDERS setting (default 3,
-        capped at 5 by the settings dialog). Their dates are computed with
+        capped at 5 by the settings dialog). Their dates are computed by
-        ``compute_reminder_offsets``: the offsets are spread uniformly across the
+        ``bal.core.reminders.build_ics_reminders`` (offsets spread uniformly
-        check-alive period and the LAST event always falls one day before the
+        across the check-alive period; the LAST event always falls one day
-        delivery deadline (locktime). If the period is shorter than the
+        before the delivery deadline / locktime). If the period is shorter than
-        requested number of reminders, at most one event per day is produced.
+        the requested number of reminders, at most one event per day is
+        produced.
 
         Each event:
             * is placed on ``locktime - offset`` days (its own visible date);
@@ -1092,103 +958,23 @@ class WillSettingsWidget(QWidget):
         path the user picks in the save dialog (default name "BAL_will_event.ics"
         on the Desktop).
         """
-        now = BalCalendar.format_time(datetime.now())
+        # The .ics content (offsets, escaping, folding, VEVENT layout) is built
-
+        # by the pure ``build_ics_reminders`` in bal.core.reminders. When no
-        # locktime = delivery deadline. It is exposed by the date widget as
+        # reminder falls in the future it returns None (ToDo #2) and the user is
-        # ``.alarm`` and already reflects the (possibly auto-anticipated) minimum
+        # warned instead of getting an empty-looking file.
-        # transaction locktime, so the calendar uses the correct delivery date.
+        ics_content = self._ics_provider()
-        locktime = self.widgets["locktime"].alarm
+        if not ics_content:
-
+            self.bal_window.show_warning(
-        # BASIC vs ADVANCED reminder strategy.
+                _(
-        #
+                    "No reminders were saved: the delivery date is too "
-        # In ADVANCED mode the reminders are spread uniformly across the
+                    "close (or already passed)"
-        # check-alive (threshold) period, ending one day before the deadline.
-        #
-        # In BASIC mode the check-alive parameter is NOT shown nor managed by the
-        # user (it stays at an arbitrary default), so spreading reminders over it
-        # is meaningless. The owner asked that, in BASIC, the calendar simply
-        # saves the inheritance delivery date with three fixed reminders: 30 days
-        # before, 10 days before and 1 day before. We also drop any fixed offset
-        # that would fall in the past (a reminder before "today" is useless), so
-        # a short-dated will still gets the reminders that are still in the
-        # future.
-        if self.bal_window.bal_plugin.is_basic_mode():
-            # Whole days from now until the delivery date. Fixed offsets (30, 10,
-            # 1 day before) are applied by basic_reminder_offsets, which also
-            # drops any offset that would fall in the past.
-            days_to_deadline = (locktime - datetime.now()).days
-            offsets = basic_reminder_offsets(days_to_deadline)
-        else:
-            # ADVANCED: spread reminders over the check-alive period as before.
-            threshold = self.widgets["threshold"].alarm
-            # Whole days available between check-alive and the deadline.
-            days = (locktime - threshold).days
-            # How many reminders the user asked for (default 3 if unreadable).
-            try:
-                count = int(self.bal_window.bal_plugin.NUM_REMINDERS.get())
-            except Exception:
-                count = 3
-            # Day-offsets BEFORE the deadline, e.g. [30, 16, 1]. The list always
-            # ends with 1 (one day before the locktime) when >= 2 reminders fit.
-            offsets = compute_reminder_offsets(days, count)
-
-        # Per-event heir details and the shared description/summary templates.
-        heirs_details = "\r\n".join(
-            f" {heir} - {self.bal_window.heirs[heir][0]}, {self.bal_window.heirs[heir][1]}"
-            for heir in self.bal_window.heirs
                 )
-        # BASIC mode: use factory defaults (the hidden settings are ignored).
-        # ADVANCED mode: use the user-configured values.
-        if self.bal_window.bal_plugin.is_basic_mode():
-            raw_description = self.bal_window.bal_plugin.EVENT_DESCRIPTION.default
-            raw_summary = self.bal_window.bal_plugin.EVENT_SUMMARY.default
-        else:
-            raw_description = self.bal_window.bal_plugin.EVENT_DESCRIPTION.get()
-            raw_summary = self.bal_window.bal_plugin.EVENT_SUMMARY.get()
-        event_description = BalCalendar.ical_escape(
-            f"{raw_description}"
-            .replace("$wallet_name", str(self.bal_window.wallet))
-            .replace("$heirs_complete", heirs_details)
-        )
-        summary_base = (
-            f"{raw_summary}"
-            .replace("$wallet_name", str(self.bal_window.wallet))
             )
+            return
 
-        lines = [
-            "BEGIN:VCALENDAR",
-            "VERSION:2.0",
-            f"PRODID:-//Bitcoin After Life//Electrum Plugin/{self.bal_window.bal_plugin.version}",
-        ]
-
-        # One separate VEVENT per reminder offset (its own date in the calendar).
-        total = len(offsets)
-        for idx, offset in enumerate(offsets, start=1):
-            # The visible date of this event: "offset" days before the deadline.
-            event_dt = BalCalendar.format_time(locktime - timedelta(days=offset))
-            # Suffix the summary so the N events are easy to tell apart.
-            summary = BalCalendar.ical_escape(
-                f"{summary_base} (reminder {idx}/{total})"
-            )
-            lines.extend([
-                "BEGIN:VEVENT",
-                # Offset in the UID keeps each event unique (no merging).
-                f"UID:bal-{str(self.bal_window.wallet)}-{offset}d",
-                f"DTSTAMP:{now}",
-                f"DTSTART:{event_dt}",
-                f"DTEND:{event_dt}",
-                f"SUMMARY:{summary}",
-                f"DESCRIPTION:{event_description}",
-                "END:VEVENT",
-            ])
-
-        lines.append("END:VCALENDAR")
-
-        lines = [s.rstrip("\r\n") for s in lines]
-        ics_content = "\r\n".join(lines) + "\r\n"
         # Keep the generated .ics in a temp file; it is copied to the path the
         # user picks below.
-        self.temp_path = BalCalendar.write_temp_ics(ics_content)
+        self.temp_path = write_temp_ics(ics_content)
 
         # Group D / D1b: always ask the user WHERE to save the .ics file (the
         # plugin no longer tries to open it with a calendar app). The save
@@ -1241,26 +1027,31 @@ class WillSettingsWidget(QWidget):
     def _ics_provider(self):
         """Return the .ics content for the current locktime/threshold values.
 
-        Used by :class:`BalCalendarButton` as its content provider.
+        Used by :class:`BalCalendarButton` as its content provider. The whole
+        document (reminder offsets, escaping, folding, VEVENT layout) is built
+        by the pure :func:`bal.core.reminders.build_ics_reminders`.
         """
-        from datetime import datetime, timedelta
-
         try:
             locktime = self.widgets["locktime"].alarm
 
-            if self.bal_window.bal_plugin.is_basic_mode():
+            basic_mode = self.bal_window.bal_plugin.is_basic_mode()
-                days_to_deadline = (locktime - datetime.now()).days
+            if basic_mode:
-                offsets = basic_reminder_offsets(days_to_deadline)
+                # BASIC mode: use factory defaults (the hidden settings are
+                # ignored) and the fixed 30/10/1 offsets.
+                raw_description = self.bal_window.bal_plugin.EVENT_DESCRIPTION.default
+                raw_summary = self.bal_window.bal_plugin.EVENT_SUMMARY.default
+                threshold = None
+                num_reminders = 3
             else:
+                raw_description = self.bal_window.bal_plugin.EVENT_DESCRIPTION.get()
+                raw_summary = self.bal_window.bal_plugin.EVENT_SUMMARY.get()
                 threshold = self.widgets["threshold"].alarm
-                days = (locktime - threshold).days
                 try:
-                    count = int(self.bal_window.bal_plugin.NUM_REMINDERS.get())
+                    num_reminders = int(
+                        self.bal_window.bal_plugin.NUM_REMINDERS.get()
+                    )
                 except Exception:
-                    count = 3
+                    num_reminders = 3
-                offsets = compute_reminder_offsets(days, count)
-
-            now = BalCalendar.format_time(datetime.now())
 
             heirs_details = "\r\n".join(
                 f" {heir} - {self.bal_window.heirs[heir][0]}, "
@@ -1268,50 +1059,17 @@ class WillSettingsWidget(QWidget):
                 for heir in self.bal_window.heirs
             )
 
-            if self.bal_window.bal_plugin.is_basic_mode():
+            return build_ics_reminders(
-                raw_description = self.bal_window.bal_plugin.EVENT_DESCRIPTION.default
+                locktime=locktime,
-                raw_summary = self.bal_window.bal_plugin.EVENT_SUMMARY.default
+                basic_mode=basic_mode,
-            else:
+                description=raw_description,
-                raw_description = self.bal_window.bal_plugin.EVENT_DESCRIPTION.get()
+                summary=raw_summary,
-                raw_summary = self.bal_window.bal_plugin.EVENT_SUMMARY.get()
+                wallet_name=str(self.bal_window.wallet),
-
+                heirs_details=heirs_details,
-            event_description = BalCalendar.ical_escape(
+                version=self.bal_window.bal_plugin.version,
-                f"{raw_description}"
+                num_reminders=num_reminders,
-                .replace("$wallet_name", str(self.bal_window.wallet))
+                threshold=threshold,
-                .replace("$heirs_complete", heirs_details)
             )
-            summary_base = (
-                f"{raw_summary}"
-                .replace("$wallet_name", str(self.bal_window.wallet))
-            )
-
-            lines = [
-                "BEGIN:VCALENDAR",
-                "VERSION:2.0",
-                "PRODID:-//Bitcoin After Life//Electrum Plugin/"
-                f"{self.bal_window.bal_plugin.version}",
-            ]
-
-            total = len(offsets)
-            for idx, offset in enumerate(offsets, start=1):
-                event_dt = BalCalendar.format_time(locktime - timedelta(days=offset))
-                summary = BalCalendar.ical_escape(
-                    f"{summary_base} (reminder {idx}/{total})"
-                )
-                lines.extend([
-                    "BEGIN:VEVENT",
-                    f"UID:bal-{str(self.bal_window.wallet)}-{offset}d",
-                    f"DTSTAMP:{now}",
-                    f"DTSTART:{event_dt}",
-                    f"DTEND:{event_dt}",
-                    f"SUMMARY:{summary}",
-                    f"DESCRIPTION:{event_description}",
-                    "END:VEVENT",
-                ])
-
-            lines.append("END:VCALENDAR")
-            lines = [s.rstrip("\r\n") for s in lines]
-            return "\r\n".join(lines) + "\r\n"
         except Exception as e:
             _logger.error(f"failed to generate .ics: {e}")
             return None
@@ -1354,40 +1112,20 @@ class PercAmountEdit(BTCAmountEdit):
         super().__init__(decimal_point, is_int, parent, max_amount=max_amount)
 
     def numbify(self):
+        # The text sanitisation lives in bal.core.input_rules.
         text = self.text().strip()
         if text == "!":
             self.shortcut.emit()
             return
         pos = self.cursorPosition()
-        chars = "0123456789%"
+        s, self.is_perc = normalize_perc_amount_text(text, DECIMAL_POINT)
-        chars += DECIMAL_POINT
-
-        s = "".join([i for i in text if i in chars])
-
-        if "%" in s:
-            self.is_perc = True
-            s = s.replace("%", "")
-        else:
-            self.is_perc = False
-
-        if DECIMAL_POINT in s:
-            p = s.find(DECIMAL_POINT)
-            s = s.replace(DECIMAL_POINT, "")
-            s = s[:p] + DECIMAL_POINT + s[p : p + 8]
-        if self.is_perc:
-            s += "%"
 
         self.setText(s)
         self.setModified(self.hasFocus())
         self.setCursorPosition(pos)
 
     def _get_amount_from_text(self, text: str) -> Union[None, Decimal, int]:
-        try:
+        return parse_perc_amount(text, DECIMAL_POINT)
-            text = text.replace(DECIMAL_POINT, ".")
-            text = text.replace("%", "")
-            return (Decimal)(text)
-        except Exception:
-            return None
 
     def _get_text_from_amount(self, amount):
         out = super()._get_text_from_amount(amount)

bal/gui/qt/window.py

@@ -14,8 +14,16 @@ The actual Bitcoin logic lives in :mod:`bal.core`; this class only coordinates
 it with the GUI.
 """
 
+import json
 import threading
 
+from electrum.util import MyEncoder
+
+from ...core.checkalive import (
+    CheckAliveError,
+    check_alive_expired,
+    resolve_date_to_check,
+)
 from .common import *
 from .common import _, _logger  # underscore names are not re-exported by "import *"
 from .dialogs import (
@@ -123,7 +131,22 @@ class BalWindow:
         for k in keys:
             del self.will[k]
         for wid, w in self.willitems.items():
-            self.will[wid] = w.to_dict()
+            d = w.to_dict()
+            # Store the tx in its serialized form: the wallet DB deep-copies
+            # every value on save (JsonDB.put), and a live Transaction carrying
+            # wallet-derived input info (utxo / script_descriptor, which hold a
+            # threading.RLock) cannot be deep-copied.  Serializing to a string
+            # matches how the will is re-read (get_will -> tx_from_any).
+            d["tx"] = str(d["tx"])
+            # Mirror the encoder the wallet DB uses: JsonDB.put returns False
+            # (silently dropping the will) when a value cannot be serialized,
+            # so prove it here and fail loudly instead.
+            try:
+                json.dumps(d, cls=MyEncoder)
+            except Exception as e:
+                _logger.error(f"save_willitems: will {wid} is not serializable: {e!r}")
+                raise
+            self.will[wid] = d
 
     def init_will(self):
         _logger.info("********************init_____will____________**********")
@@ -614,11 +637,11 @@ class BalWindow:
             # against the current moment, i.e. the Check Alive effectively does
             # not exist, while the delivery time (locktime) is still fully
             # enforced. ADVANCED mode keeps the user-controlled Check Alive
-            # exactly as before.
+            # exactly as before. The policy itself lives in
-            if self.bal_plugin.is_basic_mode():
+            # ``bal.core.checkalive.resolve_date_to_check``.
-                self.date_to_check = datetime.now().timestamp()
+            self.date_to_check = resolve_date_to_check(
-            else:
+                self.bal_plugin.is_basic_mode(), self.will_settings
-                self.date_to_check = BalTimestamp(self.will_settings['threshold']).to_timestamp()
+            )
             # found = False
             # NOTE: block-height tracking removed (A1) - locktimes are always
             # UNIX timestamps now, so we no longer read the current block height
@@ -635,9 +658,10 @@ class BalWindow:
             # flow. In BASIC we therefore SKIP this check entirely, so a passed
             # check-alive date never forces a postpone/rewrite of the will. The
             # delivery time (locktime) is unaffected and still fully enforced.
-            if (
+            # The BASIC/ADVANCED rule lives in
-                not self.bal_plugin.is_basic_mode()
+            # ``bal.core.checkalive.check_alive_expired``.
-                and self.date_to_check < datetime.now().timestamp()
+            if check_alive_expired(
+                self.bal_plugin.is_basic_mode(), self.date_to_check
             ):
                 raise CheckAliveError(self.date_to_check)
 
@@ -945,7 +969,12 @@ class BalWindow:
                 targets = Will.only_valid(willitems)
             for txid in targets:
                 wi = willitems[txid]
-                tx = copy.deepcopy(wi.tx)
+                # Do NOT deepcopy: the stored tx carries wallet-derived objects
+                # (utxo / script_descriptor) that hold a threading.RLock, and
+                # copy.deepcopy raises "cannot pickle '_thread.RLock'".  Re-parse
+                # from the serialized form instead, which is exactly how the will
+                # is persisted/loaded (WillItem.to_dict -> serialize -> tx_from_any).
+                tx = Will.get_tx_from_any(str(wi.tx))
                 if wi.get_status("COMPLETE"):
                     txs[txid] = tx
                     continue
@@ -1057,7 +1086,10 @@ class BalWindow:
         def on_success(txs):
             if txs:
                 for txid, tx in txs.items():
-                    willitems[txid].tx = copy.deepcopy(tx)
+                    # Re-parse instead of deepcopy: the signed tx may carry
+                    # wallet-derived input info holding a threading.RLock, which
+                    # copy.deepcopy cannot pickle (see sign_transactions above).
+                    willitems[txid].tx = Will.get_tx_from_any(str(tx))
                     if not external:
                         self.will[txid] = willitems[txid].to_dict()
                 try:
@@ -1251,7 +1283,9 @@ class BalWindow:
         # very first action in a session). Fall back to "now" so the local
         # validity check and the trailing update_all() always have it.
         if not hasattr(self, "date_to_check") or self.date_to_check is None:
-            self.date_to_check = datetime.now().timestamp()
+            self.date_to_check = resolve_date_to_check(
+                self.bal_plugin.is_basic_mode(), self.will_settings
+            )
 
         for wid, wi in imported.items():
             if wid in self.willitems:

tests/test_core_checkalive.py

@@ -0,0 +1,95 @@
+"""
+Tests for ``bal.core.checkalive`` (pure, GUI-free).
+
+Covers the CheckAliveError exception and the BASIC/ADVANCED date_to_check
+policy (``resolve_date_to_check`` / ``check_alive_expired``).
+
+Run:
+    source /home/steal/devel/bal/electrum/env/bin/activate
+    python3 tests/test_core_checkalive.py
+"""
+
+import sys
+import time
+
+sys.path.insert(0, __file__.rsplit("/", 2)[0])
+
+from bal.core.checkalive import (  # noqa: E402  (path insert above)
+    CheckAliveError,
+    check_alive_expired,
+    resolve_date_to_check,
+)
+
+# ------------------------------------------------------------------ #
+# CheckAliveError
+# ------------------------------------------------------------------ #
+
+
+def test_check_alive_error_default():
+    err = CheckAliveError(1000000)
+    assert err.timestamp_to_check == 1000000
+
+
+def test_check_alive_error_str():
+    err = CheckAliveError(1000000)
+    s = str(err)
+    assert "Check alive expired" in s
+    assert "1970" in s
+
+
+def test_check_alive_error_subclass():
+    assert issubclass(CheckAliveError, Exception)
+
+
+# ------------------------------------------------------------------ #
+# resolve_date_to_check
+# ------------------------------------------------------------------ #
+
+
+def test_basic_mode_uses_now():
+    fake_now = 1_800_000_000.0
+    assert resolve_date_to_check(True, {}, now=fake_now) == fake_now
+
+
+def test_advanced_mode_uses_threshold_absolute():
+    threshold = time.time() + 5 * 86400
+    settings = {"threshold": threshold}
+    result = resolve_date_to_check(False, settings)
+    assert abs(result - threshold) < 1
+
+
+def test_advanced_mode_parses_relative_threshold():
+    # "30d" resolves to a future timestamp (midnight-normalised).
+    settings = {"threshold": "30d"}
+    result = resolve_date_to_check(False, settings)
+    assert result > time.time()
+
+
+# ------------------------------------------------------------------ #
+# check_alive_expired
+# ------------------------------------------------------------------ #
+
+
+def test_basic_mode_never_expired():
+    assert check_alive_expired(True, 1_000_000_000.0) is False
+    assert check_alive_expired(True, time.time() - 10_000) is False
+
+
+def test_advanced_expired_when_past():
+    assert check_alive_expired(False, time.time() - 10_000) is True
+
+
+def test_advanced_not_expired_when_future():
+    assert check_alive_expired(False, time.time() + 10_000) is False
+
+
+# ------------------------------------------------------------------ #
+# Main
+# ------------------------------------------------------------------ #
+
+if __name__ == "__main__":
+    for name in sorted(dir()):
+        if name.startswith("test_"):
+            globals()[name]()
+            print(f"  [OK] {name}")
+    print("[OK] All core checkalive tests passed")

tests/test_core_input_rules.py

@@ -0,0 +1,165 @@
+"""
+Tests for ``bal.core.input_rules`` (pure, GUI-free).
+
+Covers the locktime acceptance bounds, the RAW locktime sanitisation, and the
+percentage-or-amount field normalisation that the Qt editors wrap.
+
+Run:
+    source /home/steal/devel/bal/electrum/env/bin/activate
+    python3 tests/test_core_input_rules.py
+"""
+
+import sys
+
+sys.path.insert(0, __file__.rsplit("/", 2)[0])
+
+from bal.core.input_rules import (  # noqa: E402  (path insert above)
+    LockTimeEditor,
+    normalize_locktime_raw_text,
+    normalize_perc_amount_text,
+    parse_perc_amount,
+    replace_dy_suffixes,
+)
+
+# ------------------------------------------------------------------ #
+# LockTimeEditor
+# ------------------------------------------------------------------ #
+
+
+def test_locktime_editor_is_acceptable():
+    assert LockTimeEditor.is_acceptable_locktime(100) is True
+    assert LockTimeEditor.is_acceptable_locktime(0) is True
+    assert LockTimeEditor.is_acceptable_locktime(-1) is False
+    assert LockTimeEditor.is_acceptable_locktime(None) is True
+
+
+def test_locktime_editor_is_acceptable_string():
+    assert LockTimeEditor.is_acceptable_locktime("100") is True
+    assert LockTimeEditor.is_acceptable_locktime("abc") is False
+    assert LockTimeEditor.is_acceptable_locktime("") is True
+
+
+def test_locktime_editor_min_max():
+    assert LockTimeEditor.min_allowed_value >= 0
+    assert LockTimeEditor.max_allowed_value > LockTimeEditor.min_allowed_value
+
+
+def test_locktime_editor_get_max_allowed_timestamp():
+    # Always a valid, fromtimestamp-able value (the Windows 2038 clamp).
+    ts = LockTimeEditor.get_max_allowed_timestamp()
+    import datetime
+
+    datetime.datetime.fromtimestamp(ts)  # must not raise
+    assert ts <= 2**32 - 1
+
+
+def test_locktime_editor_subclass_bounds():
+    class Tight(LockTimeEditor):
+        min_allowed_value = 1000
+        max_allowed_value = 2000
+
+    assert Tight.is_acceptable_locktime(1500) is True
+    assert Tight.is_acceptable_locktime(999) is False
+    assert Tight.is_acceptable_locktime(2001) is False
+
+
+# ------------------------------------------------------------------ #
+# replace_dy_suffixes / RAW locktime sanitisation
+# ------------------------------------------------------------------ #
+
+
+def test_replace_dy_suffixes():
+    # replace_str only strips the day ("d") and year ("y") suffixes. The
+    # block-height suffix ("b") was removed (A1), so "b" is NOT stripped
+    # anymore (locktimes are always UNIX timestamps now).
+    assert replace_dy_suffixes("123d") == "123"
+    assert replace_dy_suffixes("456y") == "456"
+    # "b" is left untouched (no longer a recognised suffix)
+    assert replace_dy_suffixes("789b") == "789b"
+    # only d/y are stripped; a stray "b" remains
+    assert replace_dy_suffixes("12d34y56b") == "123456b"
+
+
+def test_normalize_locktime_raw_empty():
+    s, isdays, isyears, pos = normalize_locktime_raw_text("", 0)
+    assert s == ""
+    assert isdays is False
+    assert isyears is False
+
+
+def test_normalize_locktime_raw_days():
+    s, isdays, isyears, pos = normalize_locktime_raw_text("30d", 3)
+    assert s == "30d"
+    assert isdays is True
+    assert isyears is False
+
+
+def test_normalize_locktime_raw_years():
+    s, isdays, isyears, pos = normalize_locktime_raw_text("2y", 2)
+    assert s == "2y"
+    assert isdays is False
+    assert isyears is True
+
+
+def test_normalize_locktime_raw_strips_bad_chars():
+    s, isdays, isyears, pos = normalize_locktime_raw_text("12a34b56", 8)
+    assert s == "123456"
+    assert isdays is False
+    assert isyears is False
+
+
+def test_normalize_locktime_raw_single_suffix():
+    # "1y30d" collapses to a single suffix; "d" wins (processed first), so the
+    # "y" is dropped along with all letters.
+    s, isdays, isyears, pos = normalize_locktime_raw_text("1y30d", 5)
+    assert isdays is True
+    assert isyears is False
+    assert s == "130d"
+
+
+# ------------------------------------------------------------------ #
+# Percentage-or-amount normalisation
+# ------------------------------------------------------------------ #
+
+
+def test_perc_normalize_percent():
+    s, is_perc = normalize_perc_amount_text("50%", ".")
+    assert is_perc is True
+    assert s == "50%"
+
+
+def test_perc_normalize_no_percent():
+    s, is_perc = normalize_perc_amount_text("123", ".")
+    assert is_perc is False
+    assert s == "123"
+
+
+def test_perc_normalize_strips_invalid():
+    s, is_perc = normalize_perc_amount_text("1a2b3", ".")
+    assert s == "123"
+
+
+def test_perc_normalize_decimal_limit():
+    # At most 8 decimals after the point.
+    s, is_perc = normalize_perc_amount_text("1.1234567890123", ".")
+    assert s == "1.12345678"
+
+
+def test_perc_parse():
+    from decimal import Decimal
+
+    assert parse_perc_amount("50%", ".") == Decimal(50)
+    assert parse_perc_amount("123.45", ".") == Decimal("123.45")
+    assert parse_perc_amount("abc", ".") is None
+
+
+# ------------------------------------------------------------------ #
+# Main
+# ------------------------------------------------------------------ #
+
+if __name__ == "__main__":
+    for name in sorted(dir()):
+        if name.startswith("test_"):
+            globals()[name]()
+            print(f"  [OK] {name}")
+    print("[OK] All core input_rules tests passed")

tests/test_core_reminders.py

@@ -0,0 +1,299 @@
+"""
+Tests for ``bal.core.reminders`` (pure, GUI-free).
+
+Covers the reminder-offset rules (BASIC + ADVANCED), the RFC-5545 helpers
+(format_time, ical_escape, fold_ical_line), write_temp_ics, and the unified
+``build_ics_reminders`` builder.
+
+This module imports only ``bal.core``, so it runs in the lint venv (no
+Electrum/Qt needed) as well as the runtime venv:
+
+Run:
+    python3 tests/test_core_reminders.py
+"""
+
+import os
+import sys
+from datetime import datetime, timedelta, timezone
+
+sys.path.insert(0, __file__.rsplit("/", 2)[0])
+
+from bal.core.reminders import (  # noqa: E402  (path insert above)
+    BASIC_REMINDER_OFFSETS,
+    basic_reminder_offsets,
+    build_ics_reminders,
+    compute_reminder_offsets,
+    fold_ical_line,
+    format_time,
+    ical_escape,
+    write_temp_ics,
+)
+
+# ------------------------------------------------------------------ #
+# compute_reminder_offsets - distribution rules
+# ------------------------------------------------------------------ #
+
+
+def test_offsets_long_period_three_reminders():
+    """30-day period, 3 reminders: spread out, all before the deadline."""
+    offsets = compute_reminder_offsets(30, 3)
+    assert len(offsets) == 3
+    # All strictly before the deadline (offset >= 1 means "n days before end").
+    assert all(o >= 1 for o in offsets)
+    # Sorted earliest-first (largest offset first).
+    assert offsets == sorted(offsets, reverse=True)
+    # One reminder near the start, one near the end.
+    assert max(offsets) == 30
+    assert min(offsets) == 1
+
+
+def test_offsets_capped_at_one_per_day():
+    """Short period: at most one reminder per available day."""
+    # 2 days but 3 requested -> only 2 reminders, one per day.
+    assert compute_reminder_offsets(2, 3) == [2, 1]
+    # 1 day but 3 requested -> a single reminder, the day before the deadline.
+    assert compute_reminder_offsets(1, 3) == [1]
+
+
+def test_offsets_empty_when_no_room():
+    """No reminders when there is no day before the deadline."""
+    assert compute_reminder_offsets(0, 3) == []
+    assert compute_reminder_offsets(-5, 3) == []
+    # A non-positive count also yields nothing.
+    assert compute_reminder_offsets(30, 0) == []
+
+
+def test_offsets_never_exceed_requested_count():
+    """The number of reminders never exceeds the requested count (max 5)."""
+    offsets = compute_reminder_offsets(100, 5)
+    assert len(offsets) == 5
+    assert all(o >= 1 for o in offsets)
+    # Distinct offsets only (no duplicate alarms on the same day).
+    assert len(set(offsets)) == len(offsets)
+
+
+def test_offsets_single_reminder_is_day_before_deadline():
+    """A single requested reminder fires one day before the deadline."""
+    assert compute_reminder_offsets(30, 1) == [1]
+
+
+# ------------------------------------------------------------------ #
+# basic_reminder_offsets - fixed BASIC-mode offsets
+# ------------------------------------------------------------------ #
+
+
+def test_basic_offsets_full_period():
+    """A far-away delivery keeps all three fixed offsets (30, 10, 1)."""
+    assert basic_reminder_offsets(365) == [30, 10, 1]
+
+
+def test_basic_offsets_truncated_by_horizon():
+    """Offsets beyond the delivery horizon are dropped."""
+    assert basic_reminder_offsets(20) == [10, 1]
+    assert basic_reminder_offsets(5) == [1]
+
+
+def test_basic_offsets_empty():
+    """No future offsets when the delivery is less than a day away."""
+    assert basic_reminder_offsets(0) == []
+    assert basic_reminder_offsets(-10) == []
+
+
+def test_basic_offsets_always_from_fixed_set():
+    """Every returned offset is one of the fixed BASIC offsets."""
+    for horizon in range(0, 40):
+        result = basic_reminder_offsets(horizon)
+        assert set(result).issubset(set(BASIC_REMINDER_OFFSETS))
+
+
+# ------------------------------------------------------------------ #
+# format_time
+# ------------------------------------------------------------------ #
+
+
+def test_format_time_utc():
+    dt = datetime(2025, 6, 1, 12, 30, 45, tzinfo=timezone.utc)
+    assert format_time(dt) == "20250601T123045Z"
+
+
+def test_format_time_non_utc():
+    tz = timezone(timedelta(hours=2))
+    dt = datetime(2025, 6, 1, 12, 30, 45, tzinfo=tz)
+    assert format_time(dt) == "20250601T103045Z"
+
+
+# ------------------------------------------------------------------ #
+# ical_escape
+# ------------------------------------------------------------------ #
+
+
+def test_ical_escape_no_change():
+    assert ical_escape("hello world") == "hello world"
+
+
+def test_ical_escape_backslash():
+    assert ical_escape("a\\b") == "a\\\\b"
+
+
+def test_ical_escape_semicolon():
+    assert ical_escape("a;b") == "a\\;b"
+
+
+def test_ical_escape_comma():
+    assert ical_escape("a,b") == "a\\,b"
+
+
+def test_ical_escape_multiline():
+    text = "line1\nline2"
+    result = ical_escape(text)
+    assert "line1" in result
+    assert "line2" in result
+
+
+def test_ical_escape_all():
+    assert ical_escape("\\;,") == "\\\\\\;\\,"
+
+
+# ------------------------------------------------------------------ #
+# fold_ical_line
+# ------------------------------------------------------------------ #
+
+
+def test_fold_ical_line_short():
+    assert fold_ical_line("SUMMARY:Test") == "SUMMARY:Test"
+
+
+def test_fold_ical_line_long():
+    line = "SUMMARY:" + "a" * 100
+    result = fold_ical_line(line, limit=75)
+    parts = result.split("\r\n ")
+    assert all(len(p.encode("utf-8")) <= 75 for p in parts)
+    assert "".join(parts) == line
+
+
+def test_fold_ical_line_unicode():
+    line = "SUMMARY:" + "é" * 50
+    result = fold_ical_line(line, limit=75)
+    parts = result.split("\r\n ")
+    assert all(len(p.encode("utf-8")) <= 75 for p in parts)
+    assert "".join(parts) == line
+
+
+# ------------------------------------------------------------------ #
+# write_temp_ics
+# ------------------------------------------------------------------ #
+
+
+def test_write_temp_ics():
+    content = "BEGIN:VCALENDAR\r\nEND:VCALENDAR\r\n"
+    path = write_temp_ics(content)
+    try:
+        assert os.path.isfile(path)
+        with open(path, "rb") as f:
+            assert f.read() == content.encode("utf-8")
+    finally:
+        os.unlink(path)
+
+
+def test_write_temp_ics_empty():
+    path = write_temp_ics("")
+    try:
+        assert os.path.isfile(path)
+        with open(path, "rb") as f:
+            assert f.read() == b""
+    finally:
+        os.unlink(path)
+
+
+# ------------------------------------------------------------------ #
+# build_ics_reminders - unified builder
+# ------------------------------------------------------------------ #
+
+_LOCKTIME = datetime(2026, 7, 23, 9, 0, 0, tzinfo=timezone.utc)
+
+
+def _common_kwargs():
+    return dict(
+        locktime=_LOCKTIME,
+        description="BAL will of $wallet_name\r\n$heirs_complete",
+        summary="BAL - Will execution of $wallet_name",
+        wallet_name="karen7",
+        heirs_details=" alice - bc1qalice, bob - bc1qbob",
+        version="0.6.1",
+    )
+
+
+def test_build_ics_advanced_separate_events():
+    """ADVANCED: 30-day period -> offsets [30, 16, 1], one VEVENT each."""
+    content = build_ics_reminders(
+        basic_mode=False,
+        num_reminders=3,
+        now=datetime(2026, 7, 1, 0, 0, 0, tzinfo=timezone.utc),
+        threshold=datetime(2026, 6, 23, 0, 0, 0, tzinfo=timezone.utc),
+        **_common_kwargs(),
+    )
+    assert content is not None
+    assert content.startswith("BEGIN:VCALENDAR")
+    assert content.endswith("\r\n")
+    lines = content.split("\r\n")
+    assert lines.count("BEGIN:VEVENT") == 3
+    assert lines.count("END:VEVENT") == 3
+    assert "BEGIN:VALARM" not in lines
+    # Unique UIDs, numbered summaries, last event one day before the deadline.
+    uids = [ln for ln in lines if ln.startswith("UID:")]
+    assert len(uids) == len(set(uids)) == 3
+    assert any("(reminder 1/3)" in ln for ln in lines)
+    assert any("(reminder 3/3)" in ln for ln in lines)
+    last_dt = format_time(_LOCKTIME - timedelta(days=1))
+    assert f"DTSTART:{last_dt}" in lines
+    # Template substitution; the CRLF inside the description stays as a line
+    # break in the folded DESCRIPTION (no literal "\n" escaping in ical_escape).
+    desc = [ln for ln in lines if ln.startswith("DESCRIPTION:")]
+    assert desc and "karen7" in desc[0]
+    assert any(ln.lstrip().startswith("alice") for ln in lines)
+
+def test_build_ics_basic_uses_fixed_offsets():
+    """BASIC: fixed offsets (30, 10, 1) filtered to the future, threshold not
+    required."""
+    content = build_ics_reminders(
+        basic_mode=True,
+        now=datetime(2026, 6, 1, 0, 0, 0, tzinfo=timezone.utc),
+        **_common_kwargs(),
+    )
+    assert content is not None
+    lines = content.split("\r\n")
+    uids = [ln for ln in lines if ln.startswith("UID:")]
+    assert len(uids) == 3
+    # The first event is the 30-day offset.
+    assert "bal-karen7-30d" in uids[0]
+
+
+def test_build_ics_returns_none_when_no_reminders():
+    """No future reminder -> None (the aligned behavior), not an empty file."""
+    content = build_ics_reminders(
+        basic_mode=True,
+        now=datetime(2026, 7, 23, 0, 0, 0, tzinfo=timezone.utc),
+        **_common_kwargs(),
+    )
+    assert content is None
+
+
+def test_build_ics_advanced_requires_threshold():
+    """ADVANCED mode without a threshold is a programming error."""
+    try:
+        build_ics_reminders(basic_mode=False, **_common_kwargs())
+    except ValueError:
+        return
+    raise AssertionError("expected ValueError for missing threshold in ADVANCED")
+
+
+# ------------------------------------------------------------------ #
+# Main
+# ------------------------------------------------------------------ #
+
+if __name__ == "__main__":
+    for name in sorted(dir()):
+        if name.startswith("test_"):
+            globals()[name]()
+            print(f"  [OK] {name}")
+    print("[OK] All core reminders tests passed")

tests/test_group_d_alarms.py

@@ -10,13 +10,12 @@ Covered behaviour:
     most one reminder per available day, and never returns more reminders than
     requested.
 
-``compute_reminder_offsets`` lives in ``bal.gui.qt.widgets`` (which imports
+``compute_reminder_offsets`` now lives in ``bal.core.reminders`` (pure, GUI-free),
-PyQt6), so these tests are run headless with ``QT_QPA_PLATFORM=offscreen`` like
+so these tests run without Qt (or Electrum) at all.
-the other GUI tests.
 
 Run:
-    QT_QPA_PLATFORM=offscreen PYTHONPATH=electrum-src \
+    source /home/steal/devel/bal/electrum/env/bin/activate
-        python3 -m pytest tests/test_group_d_alarms.py -q
+    python3 tests/test_group_d_alarms.py
 """
 
 import os
@@ -25,7 +24,7 @@ import sys
 sys.path.insert(0, os.path.join(os.path.dirname(__file__), os.pardir))
 
 from bal.core.plugin_base import BalConfig
-from bal.gui.qt.widgets import compute_reminder_offsets
+from bal.core.reminders import compute_reminder_offsets
 
 # ------------------------------------------------------------------ #
 # Mocks

tests/test_group_e_mock_karen7.py

@@ -37,10 +37,14 @@ import pytest  # pyright: ignore[reportMissingImports]
 sys.path.insert(0, os.path.join(os.path.dirname(__file__), os.pardir))
 
 from bal.core.heirs import Heirs
+from bal.core.reminders import (
+    compute_reminder_offsets,
+    format_time,
+    ical_escape,
+    write_temp_ics,
+)
 from bal.core.will import HeirNotFoundException, Will, WillItem
 from bal.core.willexecutors import Willexecutors
-from bal.gui.qt.calendar import BalCalendar
-from bal.gui.qt.widgets import compute_reminder_offsets
 
 # A valid serialized Bitcoin transaction hex (1 input + 1 P2PKH output,
 # version 2).  Reused from test_core_will.py so WillItem can parse a real tx.
@@ -196,8 +200,8 @@ def test_e1_build_separate_events_for_karen7():
 
     lines = ["BEGIN:VCALENDAR", "VERSION:2.0"]
     for idx, offset in enumerate(offsets, start=1):
-        event_dt = BalCalendar.format_time(locktime - timedelta(days=offset))
+        event_dt = format_time(locktime - timedelta(days=offset))
-        summary = BalCalendar.ical_escape(f"{summary_base} (reminder {idx}/{total})")
+        summary = ical_escape(f"{summary_base} (reminder {idx}/{total})")
         lines.extend([
             "BEGIN:VEVENT",
             f"UID:bal-{wallet}-{offset}d",
@@ -219,7 +223,7 @@ def test_e1_build_separate_events_for_karen7():
     assert any("(reminder 1/3)" in ln for ln in lines)
     assert any("(reminder 3/3)" in ln for ln in lines)
     # The LAST event (offset 1) sits one day before the locktime.
-    last_dt = BalCalendar.format_time(locktime - timedelta(days=1))
+    last_dt = format_time(locktime - timedelta(days=1))
     assert f"DTSTART:{last_dt}" in lines
 
 
@@ -227,7 +231,7 @@ def test_e1_event_description_escaping():
     """Special iCalendar characters in karen7's event text are escaped so
     the .ics file stays valid."""
     raw = "Wallet karen7; heirs: alice, bob"
-    escaped = BalCalendar.ical_escape(raw)
+    escaped = ical_escape(raw)
     assert "\\;" in escaped       # semicolon escaped
     assert "\\," in escaped       # comma escaped
     assert "karen7" in escaped
@@ -245,7 +249,7 @@ def test_e1_write_temp_ics_for_karen7():
         "END:VEVENT\r\n"
         "END:VCALENDAR\r\n"
     )
-    path = BalCalendar.write_temp_ics(content)
+    path = write_temp_ics(content)
     try:
         assert os.path.isfile(path)
         with open(path, "rb") as f:

tests/test_group_g_basic_calendar.py

@@ -10,13 +10,12 @@ that would fall in the past.
 These tests pin the behaviour of the pure helper ``basic_reminder_offsets`` that
 drives that decision.
 
-``basic_reminder_offsets`` lives in ``bal.gui.qt.widgets`` (which imports
+``basic_reminder_offsets`` now lives in ``bal.core.reminders`` (pure, GUI-free),
-PyQt6), so these tests are run headless with ``QT_QPA_PLATFORM=offscreen`` like
+so these tests run without Qt (or Electrum) at all.
-the other GUI tests.
 
 Run:
-    QT_QPA_PLATFORM=offscreen PYTHONPATH=electrum-src \
+    source /home/steal/devel/bal/electrum/env/bin/activate
-        python3 -m pytest tests/test_group_g_basic_calendar.py -q
+    python3 tests/test_group_g_basic_calendar.py
 """
 
 import os
@@ -24,7 +23,7 @@ import sys
 
 sys.path.insert(0, os.path.join(os.path.dirname(__file__), os.pardir))
 
-from bal.gui.qt.widgets import BASIC_REMINDER_OFFSETS, basic_reminder_offsets
+from bal.core.reminders import BASIC_REMINDER_OFFSETS, basic_reminder_offsets
 
 
 def test_basic_offsets_all_future():

tests/test_group_i_basic_checkalive.py

@@ -3,116 +3,99 @@ Tests for the "BASIC mode dynamic Check Alive" fix (Group I).
 
 Background (reported by the owner): with the plugin left in BASIC mode (the
 default), the "Check Alive" (threshold) field is hidden from the user and
-stays stuck at its old/default value (roughly "today + 11 months", i.e. one
+stays stuck at its old/default value. If the user then anticipates the
-year minus the default 30-day margin). If the user then anticipates the
+delivery time (locktime) to something earlier than that stale threshold, the
-delivery time (locktime) to something earlier than that stale threshold - e.g.
+checks that compare locktime against ``date_to_check`` would incorrectly treat
-"in 1 month" - two different checks that compare locktime against
+the will as "expired"/"invalid", even though the whole Check Alive concept is
-``date_to_check`` (the resolved threshold) would incorrectly treat the will as
+supposed to be inert in BASIC mode.
-"expired"/"invalid", even though the whole Check Alive concept is supposed to
-be inert in BASIC mode.
 
-The fix (``BalWindow.compute_date_to_check``) makes ``date_to_check`` track
+The real fix lives in ``BalWindow.init_class_variables`` (window.py), which
-the delivery time LIVE in BASIC mode, placed a fixed 2-hour margin before it,
+sets ``date_to_check`` to *now* in BASIC mode, and is now implemented by the
-so it is always < locktime by construction. In ADVANCED mode nothing changes:
+pure policy in ``bal.core.checkalive``:
-the stored threshold is used as-is.
 
-These tests call the real production method directly (no GUI/Electrum wallet
+  * ``resolve_date_to_check(is_basic_mode, will_settings)`` - the single
-needed - it is a plain ``@staticmethod``), so they exercise the exact code
+    reference timestamp: "now" in BASIC, the stored threshold in ADVANCED;
-used at runtime rather than a re-implementation.
+  * ``check_alive_expired(is_basic_mode, date_to_check)`` - whether the
+    Check-Alive guard should fire (never in BASIC).
+
+These tests exercise the exact code used at runtime (no GUI/Electrum wallet
+needed, and no Qt import).
 
 Run:
-    PYTHONPATH=electrum-src python3 -m pytest tests/test_group_i_basic_checkalive.py -q
+    source /home/steal/devel/bal/electrum/env/bin/activate
+    python3 tests/test_group_i_basic_checkalive.py
 """
 
-import os
 import sys
 import time
 
-sys.path.insert(0, os.path.join(os.path.dirname(__file__), os.pardir))
+sys.path.insert(0, __file__.rsplit("/", 2)[0])
 
-from bal.gui.qt.window import BalWindow  # noqa: E402  (path insert above)
+from bal.core.checkalive import (  # noqa: E402  (path insert above)
-
+    CheckAliveError,
-OFFSET = BalWindow.BASIC_MODE_CHECK_ALIVE_OFFSET_SECONDS
+    check_alive_expired,
+    resolve_date_to_check,
+)
 
 
-def test_offset_is_two_hours():
+def test_basic_mode_resolves_to_now():
-    """Owner-approved margin: exactly 2 hours."""
+    """BASIC mode: date_to_check is "now", never the stale stored threshold."""
-    assert OFFSET == 2 * 60 * 60
+    fake_now = 1_800_000_000.0
+    result = resolve_date_to_check(True, {"threshold": time.time() + 86400}, now=fake_now)
+    assert result == fake_now
 
 
-def _relative_days_to_midnight_timestamp(days):
+def test_basic_mode_ignores_stored_threshold():
-    """Reproduce Util.parse_locktime_string's own normalisation: "now + N
+    """BASIC + delivery anticipated to 1 month: date_to_check stays "now" and
-    days", truncated to midnight. Used to compute the expected value in
+    does NOT jump to the old ~11-month threshold - this is the exact bug
-    tests without duplicating the parsing logic itself."""
+    scenario reported by the owner."""
-    from datetime import datetime, timedelta
+    stale_threshold = time.time() + 11 * 30 * 86400  # the old stuck value
-
+    fake_now = 1_800_000_000.0
-    now = datetime.now()
+    result = resolve_date_to_check(True, {"threshold": stale_threshold}, now=fake_now)
-    return (
+    assert result == fake_now
-        (now + timedelta(days=days))
-        .replace(hour=0, minute=0, second=0, microsecond=0)
-        .timestamp()
-    )
 
 
-def test_basic_mode_relative_locktime_one_year():
+def test_advanced_mode_uses_stored_threshold():
-    """BASIC + default "1y" delivery: date_to_check tracks it, 2h earlier."""
+    """ADVANCED mode: behaviour stays exactly as before - the stored threshold
-    result = BalWindow.compute_date_to_check(True, "1y", "30d")
+    is used as-is, regardless of the locktime value."""
-    expected_locktime = _relative_days_to_midnight_timestamp(365)
-    assert abs(result - (expected_locktime - OFFSET)) < 5
-
-
-def test_basic_mode_anticipated_delivery_stays_consistent():
-    """BASIC + delivery anticipated to 1 month: date_to_check follows it,
-    NOT the old ~11-month threshold - this is the exact bug scenario
-    reported by the owner."""
-    stale_threshold = "30d"  # would resolve close to the OLD 1-year locktime
-    anticipated_locktime = "30d"  # user moved delivery to ~1 month from now
-    result = BalWindow.compute_date_to_check(
-        True, anticipated_locktime, stale_threshold
-    )
-    locktime_ts = _relative_days_to_midnight_timestamp(30)
-    # date_to_check must be (delivery - 2h), always strictly before delivery.
-    assert result < locktime_ts
-    assert abs((locktime_ts - OFFSET) - result) < 5
-
-
-def test_basic_mode_date_to_check_always_before_locktime():
-    """Regression guard for the reported bug: whatever the delivery date is
-    (even very close to "now"), date_to_check must stay before it."""
-    for relative_locktime in ("1d", "7d", "30d", "90d", "365d"):
-        result = BalWindow.compute_date_to_check(True, relative_locktime, "30d")
-        parsed_locktime = _relative_days_to_midnight_timestamp(
-            int(relative_locktime[:-1])
-        )
-        assert result < parsed_locktime, (
-            f"date_to_check ({result}) should be before locktime "
-            f"({parsed_locktime}) for locktime={relative_locktime}"
-        )
-
-
-def test_advanced_mode_uses_stored_threshold_unchanged():
-    """ADVANCED mode: behaviour must stay exactly as before this fix - the
-    stored threshold is used as-is, regardless of the locktime value."""
     absolute_threshold = time.time() + 5 * 86400  # arbitrary user-chosen value
-    result = BalWindow.compute_date_to_check(False, "30d", absolute_threshold)
+    result = resolve_date_to_check(False, {"threshold": absolute_threshold})
     assert abs(result - absolute_threshold) < 1
 
 
-def test_basic_mode_falls_back_on_unparsable_locktime():
+def test_advanced_mode_parses_relative_threshold():
-    """If the locktime can't be parsed for any reason, BASIC mode must not
+    """ADVANCED + relative threshold ("30d") resolves to a future timestamp."""
-    crash: it falls back to the stored threshold, same as ADVANCED."""
+    result = resolve_date_to_check(False, {"threshold": "30d"})
-    absolute_threshold = time.time() + 5 * 86400
+    assert result > time.time()
-    result = BalWindow.compute_date_to_check(
+
-        True, {"not": "a valid locktime"}, absolute_threshold
+
-    )
+def test_basic_mode_never_expired():
-    assert abs(result - absolute_threshold) < 1
+    """BASIC mode can never be "expired": a passed check-alive date must never
+    force a postpone/rewrite of the will."""
+    assert check_alive_expired(True, time.time() - 10_000) is False
+    assert check_alive_expired(True, 1_000_000_000.0) is False
+
+
+def test_advanced_mode_expired_when_past():
+    assert check_alive_expired(False, time.time() - 10_000) is True
+
+
+def test_advanced_mode_not_expired_when_future():
+    assert check_alive_expired(False, time.time() + 10_000) is False
+
+
+def test_basic_mode_never_raises_check_alive_error():
+    """Regression guard for the reported bug: whatever the delivery date,
+    BASIC mode never raises CheckAliveError (the postpone/invalidate trigger)."""
+    date_to_check = resolve_date_to_check(True, {"threshold": "30d"})
+    assert not check_alive_expired(True, date_to_check)
+    # If it did fire, this is the exact exception that would be raised.
+    assert issubclass(CheckAliveError, Exception)
 
 
 if __name__ == "__main__":
-    test_offset_is_two_hours()
+    for name in sorted(dir()):
-    test_basic_mode_relative_locktime_one_year()
+        if name.startswith("test_"):
-    test_basic_mode_anticipated_delivery_stays_consistent()
+            globals()[name]()
-    test_basic_mode_date_to_check_always_before_locktime()
+            print(f"  [OK] {name}")
-    test_advanced_mode_uses_stored_threshold_unchanged()
+    print("[OK] All test_group_i_basic_checkalive tests passed.")
-    test_basic_mode_falls_back_on_unparsable_locktime()
-    print("All test_group_i_basic_checkalive tests passed.")

tests/test_gui_calendar.py

@@ -1,126 +1,25 @@
 """
 Tests for ``bal.gui.qt.calendar``.
 
-Covers BalCalendar static methods: format_time, ical_escape, fold_ical_line,
+Covers the GUI/OS glue that stayed in this module: BalCalendar.open_with_default_app.
-write_temp_ics, open_with_default_app.
+The RFC-5545 helpers (format_time, ical_escape, fold_ical_line, write_temp_ics)
+moved to ``bal.core.reminders`` and are tested in ``tests/test_core_reminders.py``.
 
 Run:
     QT_QPA_PLATFORM=offscreen python3 tests/test_gui_calendar.py
 """
 
-import os
 import sys
-from datetime import datetime, timezone
 
 sys.path.insert(0, __file__.rsplit("/", 2)[0])
 
 from bal.gui.qt.calendar import BalCalendar
 
-# ------------------------------------------------------------------ #
-# format_time
-# ------------------------------------------------------------------ #
-
-def test_format_time_utc():
-    dt = datetime(2025, 6, 1, 12, 30, 45, tzinfo=timezone.utc)
-    assert BalCalendar.format_time(dt) == "20250601T123045Z"
-
-
-def test_format_time_non_utc():
-    from datetime import timedelta
-    tz = timezone(timedelta(hours=2))
-    dt = datetime(2025, 1, 15, 8, 0, 0, tzinfo=tz)
-    result = BalCalendar.format_time(dt)
-    assert result.endswith("Z")
-    assert result == "20250115T060000Z"
-
-
-# ------------------------------------------------------------------ #
-# ical_escape
-# ------------------------------------------------------------------ #
-
-def test_ical_escape_no_change():
-    text = "hello world"
-    assert BalCalendar.ical_escape(text) == "hello world"
-
-
-def test_ical_escape_backslash():
-    assert BalCalendar.ical_escape("a\\b") == "a\\\\b"
-
-
-def test_ical_escape_semicolon():
-    assert BalCalendar.ical_escape("a;b") == "a\\;b"
-
-
-def test_ical_escape_comma():
-    assert BalCalendar.ical_escape("a,b") == "a\\,b"
-
-
-def test_ical_escape_multiline():
-    text = "line1\r\nline2"
-    result = BalCalendar.ical_escape(text)
-    assert "\r\n" in result
-    assert "line1" in result
-    assert "line2" in result
-
-
-def test_ical_escape_all():
-    text = "\\;,"
-    assert BalCalendar.ical_escape(text) == "\\\\\\;\\,"
-
-
-# ------------------------------------------------------------------ #
-# fold_ical_line
-# ------------------------------------------------------------------ #
-
-def test_fold_ical_line_short():
-    line = "SUMMARY:Test"
-    assert BalCalendar.fold_ical_line(line) == "SUMMARY:Test"
-
-
-def test_fold_ical_line_long():
-    line = "X-LONG:" + "a" * 100
-    result = BalCalendar.fold_ical_line(line, limit=75)
-    parts = result.split("\r\n ")
-    assert len(parts) > 1
-    assert result.startswith("X-LONG:")
-
-
-def test_fold_ical_line_unicode():
-    line = "DESCRIPTION:" + "\u20ac" * 40
-    result = BalCalendar.fold_ical_line(line, limit=75)
-    assert "\r\n " in result
-    assert "\u20ac" in result
-
-
-# ------------------------------------------------------------------ #
-# write_temp_ics
-# ------------------------------------------------------------------ #
-
-def test_write_temp_ics():
-    content = "BEGIN:VCALENDAR\r\nEND:VCALENDAR\r\n"
-    path = BalCalendar.write_temp_ics(content)
-    try:
-        assert os.path.isfile(path)
-        with open(path, "rb") as f:
-            assert f.read() == content.encode("utf-8")
-    finally:
-        os.unlink(path)
-
-
-def test_write_temp_ics_empty():
-    path = BalCalendar.write_temp_ics("")
-    try:
-        assert os.path.isfile(path)
-        with open(path, "rb") as f:
-            assert f.read() == b""
-    finally:
-        os.unlink(path)
-
-
 # ------------------------------------------------------------------ #
 # open_with_default_app
 # ------------------------------------------------------------------ #
 
+
 def test_open_with_default_app_not_found():
     result = BalCalendar.open_with_default_app(
         "/nonexistent/calendar_app", "/tmp/fake.ics"

tests/test_gui_common.py

@@ -1,7 +1,8 @@
 """
 Tests for ``bal.gui.qt.common``.
 
-Covers shown_cv, CheckAliveError, add_widget, log_error, export_meta_gui.
+Covers shown_cv, add_widget, log_error, export_meta_gui (and the
+CheckAliveError exception, which now lives in ``bal.core.checkalive``).
 
 Run:
     QT_QPA_PLATFORM=offscreen python3 tests/test_gui_common.py
@@ -44,23 +45,30 @@ def test_shown_cv_roundtrip():
 
 
 # ------------------------------------------------------------------ #
-# CheckAliveError
+# CheckAliveError (moved to bal.core.checkalive; kept tested via the
+# common->core import chain)
 # ------------------------------------------------------------------ #
 
 def test_check_alive_error_default():
-    err = common.CheckAliveError(1000000)
+    from bal.core.checkalive import CheckAliveError
+
+    err = CheckAliveError(1000000)
     assert err.timestamp_to_check == 1000000
 
 
 def test_check_alive_error_str():
-    err = common.CheckAliveError(1000000)
+    from bal.core.checkalive import CheckAliveError
+
+    err = CheckAliveError(1000000)
     s = str(err)
     assert "Check alive expired" in s
     assert "1970" in s
 
 
 def test_check_alive_error_subclass():
-    assert issubclass(common.CheckAliveError, Exception)
+    from bal.core.checkalive import CheckAliveError
+
+    assert issubclass(CheckAliveError, Exception)
 
 
 # ------------------------------------------------------------------ #

tests/test_gui_widgets.py

@@ -118,23 +118,25 @@ def test_locktime_editor_min_max():
 def test_locktime_raw_edit_replace_str():
     # replace_str only strips the day ("d") and year ("y") suffixes. The
     # block-height suffix ("b") was removed (A1), so "b" is NOT stripped
-    # anymore (locktimes are always UNIX timestamps now).
+    # anymore (locktimes are always UNIX timestamps now). The helper moved to
-    from bal.gui.qt.widgets import LockTimeRawEdit
+    # bal.core.input_rules (replace_dy_suffixes); the widget delegates to it.
-    assert LockTimeRawEdit.replace_str("123d") == "123"
+    from bal.core.input_rules import replace_dy_suffixes
-    assert LockTimeRawEdit.replace_str("456y") == "456"
+    assert replace_dy_suffixes("123d") == "123"
+    assert replace_dy_suffixes("456y") == "456"
     # "b" is left untouched (no longer a recognised suffix)
-    assert LockTimeRawEdit.replace_str("789b") == "789b"
+    assert replace_dy_suffixes("789b") == "789b"
     # only d/y are stripped; a stray "b" remains
-    assert LockTimeRawEdit.replace_str("12d34y56b") == "123456b"
+    assert replace_dy_suffixes("12d34y56b") == "123456b"
 
 
 def test_locktime_raw_edit_checkbdy():
-    from bal.gui.qt.widgets import LockTimeRawEdit
+    # checkbdy moved to bal.core.input_rules (_checkbdy).
+    from bal.core.input_rules import _checkbdy
     # character at expected position matches appendix
-    pos, s = LockTimeRawEdit.checkbdy(None, "123d", 4, "d")
+    pos, s = _checkbdy("123d", 4, "d")
     assert s == "123d"
     # character at expected position does not match
-    pos, s = LockTimeRawEdit.checkbdy(None, "123x", 4, "d")
+    pos, s = _checkbdy("123x", 4, "d")
     assert s == "123x"
 
 

tests/test_import_will_details.py

@@ -305,10 +305,14 @@ def _make_merge_fake(willitems):
         wallet=FakeWallet(),
         bal_window=None,
         date_to_check=1700000000,
+        will_settings={"threshold": 1700000000},
         bal_plugin=SimpleNamespace(
             HISTORY_LABEL=SimpleNamespace(
                 get=lambda: "BAL will history ({willexecutor})"
-            )
+            ),
+            # BASIC is the default user type; merge_will resolves date_to_check
+            # through bal.core.checkalive when it is missing.
+            is_basic_mode=lambda: True,
         ),
         update_all=lambda: calls.append("update_all"),
     )