Release v2.19.4 (#259)

Release v2.19.4.

**Fixed**
- A deleted occurrence stays deleted through a series re-timing, and through backup/restore ([#225]).
- "Only this event" saves the edit on calendars that never synced, and on a row that doesn't recur it edits or deletes the event itself instead of filing an exception against nothing.
- A reminder left on the account's default is no longer read as a lead time of Calendula's own.
- The widgets turn the page at midnight; the re-arm backstop for the inexact rollover alarm is back, throttled to once per 15 minutes on calendar changes.
- An event running past midnight can be dragged by either half ([#253]).
- One event the provider refuses no longer costs the rest of the import, and an import cut short reports honestly how far it got.
- EXDATE zone prefixes are read in the bare `<zone>;` form the provider and DAVx5 actually write, not only the iCalendar `TZID=` spelling; a list holding a stamp we can't parse is kept whole rather than re-emitted stripped of its zone; RDATE travels with RRULE when the recurrence set is rewritten.

**Added**
- Belarusian, Hungarian and Slovak, from community translators on Weblate.

**Changed**
- Arabic, Polish and Simplified Chinese are complete; Czech grew, and Russian is now at about half.

Bumps `versionName` to 2.19.4, so merging this triggers the release pipeline.

Co-authored-by: Jean-Luc Makiola <business@jeanlucmakiola.de>
Reviewed-on: https://codeberg.org/jlmakiola/calendula/pulls/259

app/src/test/java/de/jeanlucmakiola/calendula/data/calendar/AllDayReminderEncodingTest.kt

@@ -143,6 +143,76 @@ class AllDayReminderEncodingTest {
         assertThat(fireFromNext).isEqualTo(LocalTime.of(9, 0)) // correct
     }
 
+    @Test
+    fun `an imported yearly series samples at its next occurrence, not its anchor`() {
+        // Fossify anchors a year-less contact birthday at 1970, when Berlin had
+        // no DST; sampling there fires a modern June occurrence at 10:00 instead
+        // of the 09:00 the user picked (Codeberg #225).
+        val anchor = LocalDate.of(1970, 6, 3)
+        val today = LocalDate.of(2026, 6, 1)
+
+        val sampled = importedAllDayReminderDate(anchor, "FREQ=YEARLY;BYMONTH=6", today)
+        assertThat(sampled).isEqualTo(LocalDate.of(2026, 6, 3))
+
+        val raw = toProviderAllDayMinutes(0, sampled, berlin, nineAm)
+        val fire = actualFire(raw, LocalDate.of(2027, 6, 3))
+            .let(java.time.Instant::ofEpochMilli).atZone(berlin).toLocalTime()
+        assertThat(fire).isEqualTo(LocalTime.of(9, 0))
+    }
+
+    @Test
+    fun `the lead time still reads back from the anchor's own date`() {
+        // The offset is sampled at the next occurrence but decoded against
+        // DTSTART, so the two must still agree on the whole-day lead time.
+        val anchor = LocalDate.of(1970, 6, 3)
+        val sampled = importedAllDayReminderDate(anchor, "FREQ=YEARLY", LocalDate.of(2026, 6, 1))
+
+        for (semantic in listOf(0, 1_440, 2_880)) {
+            val raw = toProviderAllDayMinutes(semantic, sampled, berlin, nineAm)
+            assertThat(fromProviderAllDayMinutes(raw, anchor, berlin, nineAm)).isEqualTo(semantic)
+        }
+    }
+
+    @Test
+    fun `a one-off import samples at its own date, a stale series at today`() {
+        val past = LocalDate.of(1970, 6, 3)
+        val today = LocalDate.of(2026, 6, 1)
+        val future = LocalDate.of(2027, 3, 4)
+
+        assertThat(importedAllDayReminderDate(past, null, today)).isEqualTo(past)
+        assertThat(importedAllDayReminderDate(past, "FREQ=WEEKLY;BYDAY=MO", today)).isEqualTo(today)
+        assertThat(importedAllDayReminderDate(future, "FREQ=WEEKLY", today)).isEqualTo(future)
+    }
+
+    @Test
+    fun `the provider default sentinel survives a round trip untouched`() {
+        // -1 is Reminders.MINUTES_DEFAULT, not an offset. Decoded it landed on
+        // the start date and came back as 0 — a concrete at-start alarm on the
+        // detail screen and in an exported file.
+        assertThat(toProviderAllDayMinutes(-1, winter, berlin, nineAm)).isEqualTo(-1)
+        assertThat(fromProviderAllDayMinutes(-1, winter, berlin, nineAm)).isEqualTo(-1)
+    }
+
+    @Test
+    fun `a real encoding that is negative is still decoded`() {
+        // "At time of event" encodes negative — the sentinel check must be the
+        // exact value, not any negative one.
+        val raw = toProviderAllDayMinutes(0, winter, berlin, nineAm)
+        assertThat(raw).isLessThan(0)
+        assertThat(fromProviderAllDayMinutes(raw, winter, berlin, nineAm)).isEqualTo(0)
+    }
+
+    @Test
+    fun `an encoding that would land on the sentinel is nudged off it`() {
+        // 01:01 Berlin in winter (CET, +1) is 00:01 UTC — one minute past the
+        // event's UTC-midnight DTSTART, i.e. exactly -1. Left there it would read
+        // back as "use the account default" and the real reminder would be gone
+        // from the screen and from an export.
+        val raw = toProviderAllDayMinutes(0, winter, berlin, 61)
+        assertThat(raw).isEqualTo(-2)
+        assertThat(fromProviderAllDayMinutes(raw, winter, berlin, 61)).isEqualTo(0)
+    }
+
     @Test
     fun `a winter-anchored offset drifts one hour on a summer occurrence`() {
         // Known limitation: one fixed MINUTES per series can't track DST. An

app/src/test/java/de/jeanlucmakiola/calendula/data/calendar/CalendarRepositoryImplTest.kt

@@ -22,6 +22,7 @@ import kotlinx.coroutines.test.UnconfinedTestDispatcher
 import kotlinx.coroutines.test.runTest
 import kotlin.time.Instant
 import org.junit.jupiter.api.Test
+import org.junit.jupiter.api.assertThrows
 import org.junit.jupiter.api.io.TempDir
 import java.nio.file.Path
 
@@ -642,7 +643,12 @@ class CalendarRepositoryImplTest {
             end = LocalDateTime(LocalDate(2026, 6, 12), LocalTime(10, 0)),
         )
 
-        val id = repo.updateOccurrence(eventId = 42L, beginMillis = 1_000L, form = form)
+        val id = repo.updateOccurrence(
+            eventId = 42L,
+            beginMillis = 1_000L,
+            original = form,
+            form = form,
+        )
 
         assertThat(id).isEqualTo(88L)
         assertThat(fake.updatedOccurrences).containsExactly(Triple(42L, 1_000L, form))
@@ -801,6 +807,113 @@ class CalendarRepositoryImplTest {
         assertThat(fake.importedEvents.map { it.second }).containsExactly(3L, 3L)
     }
 
+    @Test
+    fun `importEvents carries on past an event the provider rejects`(
+        @TempDir tempDir: Path,
+    ) = runTest {
+        // A foreign export can hold a row the provider throws on outright; that
+        // must cost the user one event, not the whole file (Codeberg #225).
+        val fake = FakeCalendarDataSource().apply { failingImportSummaries += "bad" }
+        val repo = CalendarRepositoryImpl(fake, newPrefs(tempDir), newSettings(tempDir), Dispatchers.Unconfined)
+        val events = listOf(
+            parsedEvent("a@x", summary = "good"),
+            parsedEvent("b@x", summary = "bad"),
+            parsedEvent("c@x", summary = "good"),
+        )
+
+        val summary = repo.importEvents(targetCalendarId = 3L, events = events)
+
+        assertThat(summary.imported).isEqualTo(2)
+        assertThat(summary.failed).isEqualTo(1)
+        assertThat(fake.importedEvents.map { it.first.uid }).containsExactly("a@x", "c@x")
+    }
+
+    @Test
+    fun `importEvents stops at a permission failure and reports what landed`(
+        @TempDir tempDir: Path,
+    ) = runTest {
+        // The permission or the target calendar is gone, so every remaining insert
+        // would fail the same way. Counted per event, the screen reported "N events
+        // couldn't be added" for a file it never had a chance at; thrown, it
+        // reported that nothing landed — and since only events carrying a UID dedup,
+        // the retry that invites duplicated everything that already had.
+        val fake = FakeCalendarDataSource().apply {
+            importsBeforeError = 2
+            writeError = SecurityException("WRITE_CALENDAR revoked")
+        }
+        val repo = CalendarRepositoryImpl(fake, newPrefs(tempDir), newSettings(tempDir), Dispatchers.Unconfined)
+
+        val summary = repo.importEvents(
+            targetCalendarId = 3L,
+            events = List(5) { parsedEvent("e$it@x") },
+        )
+
+        assertThat(summary.imported).isEqualTo(2)
+        // The one that threw and the two never reached.
+        assertThat(summary.notAttempted).isEqualTo(3)
+        assertThat(summary.failed).isEqualTo(0)
+    }
+
+    @Test
+    fun `a stopped import does not count known duplicates as work left to do`(
+        @TempDir tempDir: Path,
+    ) = runTest {
+        // The remainder is not all work: a UID already in the calendar would have
+        // been skipped whatever happened, so counting it against a retry
+        // overstates how much of the file is missing.
+        val fake = FakeCalendarDataSource().apply {
+            existingUidsResult = setOf("e3@x", "e4@x")
+            importsBeforeError = 1
+            writeError = SecurityException("WRITE_CALENDAR revoked")
+        }
+        val repo = CalendarRepositoryImpl(fake, newPrefs(tempDir), newSettings(tempDir), Dispatchers.Unconfined)
+
+        val summary = repo.importEvents(
+            targetCalendarId = 3L,
+            events = List(5) { parsedEvent("e$it@x") },
+        )
+
+        assertThat(summary.imported).isEqualTo(1)
+        // e1 threw and e2 was never reached; e3 and e4 were duplicates either way.
+        assertThat(summary.notAttempted).isEqualTo(2)
+        assertThat(summary.skippedDuplicate).isEqualTo(2)
+    }
+
+    @Test
+    fun `importEvents looks the target palette up once, not per event`(
+        @TempDir tempDir: Path,
+    ) = runTest {
+        var lookups = 0
+        val fake = FakeCalendarDataSource().apply {
+            publishedEventColorsResult = { lookups++; emptyList() }
+        }
+        val repo = CalendarRepositoryImpl(fake, newPrefs(tempDir), newSettings(tempDir), Dispatchers.Unconfined)
+
+        repo.importEvents(3L, List(5) { parsedEvent("e$it@x") })
+
+        assertThat(lookups).isEqualTo(1)
+    }
+
+    @Test
+    fun `importEvents matches colours against the uncurated palette`(
+        @TempDir tempDir: Path,
+    ) = runTest {
+        // Curation is a picker concession — it folds look-alikes and drops the
+        // neutrals from an oversized palette — but every published key is one
+        // the calendar accepts, so an imported colour matches against all of
+        // them (Codeberg #225).
+        val published = listOf(EventColorOption("1", 0xFF808080.toInt()))
+        val fake = FakeCalendarDataSource().apply {
+            publishedEventColorsResult = { published }
+            eventColorPaletteResult = { emptyList() }
+        }
+        val repo = CalendarRepositoryImpl(fake, newPrefs(tempDir), newSettings(tempDir), Dispatchers.Unconfined)
+
+        repo.importEvents(3L, listOf(parsedEvent("a@x")))
+
+        assertThat(fake.lastImportPalette).isEqualTo(published)
+    }
+
     @Test
     fun `exportEvents forwards the chosen calendar-id subset to the data source`(
         @TempDir tempDir: Path,
@@ -825,9 +938,10 @@ class CalendarRepositoryImplTest {
         assertThat(fake.lastExportableEventsCalendarIds).isNull()
     }
 
-    private fun parsedEvent(uid: String?) = de.jeanlucmakiola.calendula.domain.ics.ParsedIcsEvent(
+    private fun parsedEvent(uid: String?, summary: String = "E") =
+        de.jeanlucmakiola.calendula.domain.ics.ParsedIcsEvent(
         uid = uid,
-        summary = "E",
+        summary = summary,
         start = Instant.fromEpochMilliseconds(1_000_000_000L),
         end = Instant.fromEpochMilliseconds(1_000_003_600L),
         isAllDay = false,

app/src/test/java/de/jeanlucmakiola/calendula/data/calendar/EventWriteMapperTest.kt

@@ -498,6 +498,7 @@ class EventWriteMapperTest {
             occurrenceMillis = 1_784_102_400_000L,
             dtStartMillis = 1_783_929_600_000L,
             rrule = "FREQ=DAILY;COUNT=5",
+            rdate = null,
             duration = "PT1H",
             timezone = "Europe/Berlin",
             allDay = 0,
@@ -521,6 +522,7 @@ class EventWriteMapperTest {
             occurrenceMillis = 1_784_102_400_000L,
             dtStartMillis = 1_783_929_600_000L,
             rrule = "FREQ=DAILY;COUNT=5",
+            rdate = null,
             duration = "PT1H",
             timezone = "Europe/Berlin",
             allDay = 0,
@@ -536,6 +538,7 @@ class EventWriteMapperTest {
             occurrenceMillis = 1_784_102_400_000L,
             dtStartMillis = 1_783_929_600_000L,
             rrule = "FREQ=DAILY;COUNT=5",
+            rdate = null,
             duration = "PT1H",
             timezone = "Europe/Berlin",
             allDay = 0,
@@ -543,6 +546,27 @@ class EventWriteMapperTest {
         assertThat(values[CalendarContract.Events.EXDATE]).isEqualTo("20260715T080000Z")
     }
 
+    @Test
+    fun `an all-day drop folds away a padded repeat of the same day`() {
+        // Compared verbatim, the two spellings of 15 July are different strings:
+        // the day ends up excluded twice, and exdateContains — the guard against
+        // detaching the same occurrence twice — misses it entirely.
+        val occurrence = 1_784_073_600_000L // 2026-07-15T00:00:00Z
+        val values = buildOccurrenceExdateValues(
+            existingExdate = "20260715T000000Z",
+            occurrenceMillis = occurrence,
+            dtStartMillis = 1_783_900_800_000L,
+            rrule = "FREQ=WEEKLY",
+            rdate = null,
+            duration = "P1D",
+            timezone = "UTC",
+            allDay = 1,
+        )
+        assertThat(values[CalendarContract.Events.EXDATE]).isEqualTo("20260715")
+        assertThat(exdateContains("20260715T000000Z", occurrence, isAllDay = true, timezone = null))
+            .isTrue()
+    }
+
     @Test
     fun `all-day exdate drop uses the date-only form`() {
         // An all-day DTSTART sits at UTC midnight, so the date reads off UTC.
@@ -551,6 +575,7 @@ class EventWriteMapperTest {
             occurrenceMillis = 1_784_073_600_000L, // 2026-07-15T00:00:00Z
             dtStartMillis = 1_783_900_800_000L,
             rrule = "FREQ=YEARLY",
+            rdate = null,
             duration = "P1D",
             timezone = "UTC",
             allDay = 1,
@@ -559,6 +584,90 @@ class EventWriteMapperTest {
         assertThat(values[CalendarContract.Events.ALL_DAY]).isEqualTo(1)
     }
 
+    @Test
+    fun `an exdate list zoned the way the provider writes it is read in that zone`() {
+        // AOSP's RecurrenceSet keeps the TZID parameter's *value*, not the
+        // parameter: `Europe/Berlin;<stamps>`, no `TZID=`. Matching only the
+        // iCalendar spelling read every list the provider itself wrote as if its
+        // floating stamps were UTC — hours off for any zone but UTC.
+        assertThat(exdateListZone("Europe/Berlin;20260708T100000", "UTC"))
+            .isEqualTo(ZoneId.of("Europe/Berlin"))
+        assertThat(exdateListZone("TZID=Europe/Berlin;20260708T100000", "UTC"))
+            .isEqualTo(ZoneId.of("Europe/Berlin"))
+        // No prefix, or one this device can't place: the row's own zone.
+        assertThat(exdateListZone("20260708T100000", "Europe/Berlin"))
+            .isEqualTo(ZoneId.of("Europe/Berlin"))
+        assertThat(exdateListZone("W. Europe Standard Time;20260708T100000", "Europe/Berlin"))
+            .isEqualTo(ZoneId.of("Europe/Berlin"))
+    }
+
+    @Test
+    fun `a bare-zoned exclusion list splits on the instants its prefix names`() {
+        assertThat(
+            exdateAfter(
+                "Europe/Berlin;20260708T100000,20260729T100000",
+                instantAt("2026-07-15T08:00", "UTC"),
+                isAllDay = false,
+                timezone = null,
+            ),
+        ).isEqualTo("20260729T080000Z")
+    }
+
+    @Test
+    fun `an exdate drop keeps a list it cannot read whole, prefix and all`() {
+        // Stripping the prefix off a list and re-emitting the stamps it can't
+        // parse leaves them floating: "09:00 in Berlin" silently becomes 09:00 in
+        // whatever zone the next reader picks.
+        val values = buildOccurrenceExdateValues(
+            existingExdate = "Europe/Berlin;20260722T090000",
+            occurrenceMillis = 1_784_073_600_000L, // 2026-07-15T00:00:00Z
+            dtStartMillis = 1_783_900_800_000L,
+            rrule = "FREQ=WEEKLY",
+            rdate = null,
+            duration = "P1D",
+            timezone = "Europe/Berlin",
+            allDay = 1,
+        )
+        assertThat(values[CalendarContract.Events.EXDATE])
+            .isEqualTo("Europe/Berlin;20260722T090000,20260715")
+    }
+
+    @Test
+    fun `a new exclusion joins an unreadable timed list in that list's own form`() {
+        val values = buildOccurrenceExdateValues(
+            existingExdate = "Europe/Berlin;sometime next Tuesday",
+            occurrenceMillis = 1_784_102_400_000L, // 2026-07-15T08:00:00Z == 10:00 Berlin
+            dtStartMillis = 1_783_929_600_000L,
+            rrule = "FREQ=DAILY",
+            rdate = null,
+            duration = "PT1H",
+            timezone = "Europe/Berlin",
+            allDay = 0,
+        )
+        assertThat(values[CalendarContract.Events.EXDATE])
+            .isEqualTo("Europe/Berlin;sometime next Tuesday,20260715T100000")
+    }
+
+    @Test
+    fun `an exdate drop rewrites RDATE along with the rule`() {
+        // A series may be a list of dates with no rule at all. Left out of the
+        // rewrite, the provider has only DTSTART to re-expand from and collapses
+        // the series to its first occurrence.
+        val values = buildOccurrenceExdateValues(
+            existingExdate = null,
+            occurrenceMillis = 1_784_102_400_000L,
+            dtStartMillis = 1_783_929_600_000L,
+            rrule = null,
+            rdate = "20260716T080000Z,20260722T080000Z",
+            duration = "PT1H",
+            timezone = "Europe/Berlin",
+            allDay = 0,
+        )
+        assertThat(values[CalendarContract.Events.RDATE])
+            .isEqualTo("20260716T080000Z,20260722T080000Z")
+        assertThat(values[CalendarContract.Events.RRULE]).isNull()
+    }
+
     // --- EXDATE follows the series when its times change (Codeberg #248) ---
 
     /** A weekly series whose displayed occurrence runs 15 July 2026, 09:00–10:00. */
@@ -627,6 +736,65 @@ class EventWriteMapperTest {
             .isEqualTo("20260724")
     }
 
+    @Test
+    fun `an all-day exclusion a sync adapter padded still moves with the series`() {
+        // The bug: only the bare yyyyMMdd form parsed, so a padded midnight stamp
+        // bailed the whole list and buildEventUpdateValues wrote no EXDATE at all
+        // — the deleted occurrence came back the moment the series was re-timed.
+        val series = instantAt("2026-07-01T00:00", "UTC")
+        val original = form(
+            isAllDay = true,
+            start = LocalDateTime(LocalDate(2026, 7, 15), LocalTime(0, 0)),
+            end = LocalDateTime(LocalDate(2026, 7, 15), LocalTime(0, 0)),
+        ).copy(rrule = "FREQ=WEEKLY")
+        val moved = original.copy(
+            start = LocalDateTime(LocalDate(2026, 7, 17), LocalTime(0, 0)),
+            end = LocalDateTime(LocalDate(2026, 7, 17), LocalTime(0, 0)),
+        )
+
+        val values = update(original, moved, series, "20260722T000000Z")
+        assertThat(values[CalendarContract.Events.EXDATE]).isEqualTo("20260724")
+    }
+
+    @Test
+    fun `an all-day exclusion padded without a Z is read the same way`() {
+        // DAVx5 and AOSP's own RecurrenceSet write a floating midnight for a
+        // date value. Only the trailing-Z spelling parsed, so the floating one
+        // bailed the whole list and the deleted occurrence came back.
+        val series = instantAt("2026-07-01T00:00", "UTC")
+        val original = form(
+            isAllDay = true,
+            start = LocalDateTime(LocalDate(2026, 7, 15), LocalTime(0, 0)),
+            end = LocalDateTime(LocalDate(2026, 7, 15), LocalTime(0, 0)),
+        ).copy(rrule = "FREQ=WEEKLY")
+        val moved = original.copy(
+            start = LocalDateTime(LocalDate(2026, 7, 17), LocalTime(0, 0)),
+            end = LocalDateTime(LocalDate(2026, 7, 17), LocalTime(0, 0)),
+        )
+
+        val values = update(original, moved, series, "20260722T000000")
+        assertThat(values[CalendarContract.Events.EXDATE]).isEqualTo("20260724")
+    }
+
+    @Test
+    fun `a padded all-day stamp naming any other time is still left alone`() {
+        // Not a form an all-day series is written in, so it could be naming
+        // something else entirely — guessing could exclude the wrong occurrence.
+        val series = instantAt("2026-07-01T00:00", "UTC")
+        val original = form(
+            isAllDay = true,
+            start = LocalDateTime(LocalDate(2026, 7, 15), LocalTime(0, 0)),
+            end = LocalDateTime(LocalDate(2026, 7, 15), LocalTime(0, 0)),
+        ).copy(rrule = "FREQ=WEEKLY")
+        val moved = original.copy(
+            start = LocalDateTime(LocalDate(2026, 7, 17), LocalTime(0, 0)),
+            end = LocalDateTime(LocalDate(2026, 7, 17), LocalTime(0, 0)),
+        )
+
+        val values = update(original, moved, series, "20260722T090000Z")
+        assertThat(values).doesNotContainKey(CalendarContract.Events.EXDATE)
+    }
+
     @Test
     fun `switching a series to all-day rewrites its exclusions as dates`() {
         // The two forms aren't interchangeable: a date-time stamp on an all-day
@@ -673,9 +841,10 @@ class EventWriteMapperTest {
     }
 
     @Test
-    fun `an exdate form we do not write is left untouched`() {
-        // A sync adapter may store a TZID-parameterised or floating stamp. A stale
-        // stamp excludes nothing; a mangled one could exclude the wrong occurrence.
+    fun `a zoned exdate list is read in the zone its prefix names`() {
+        // AOSP's RecurrenceSet form, TZID=<zone>;<floating stamps>. Read as UTC the
+        // stamps name the wrong instants; skipped, every exclusion of the series is
+        // dropped the moment it is re-timed.
         val original = julySeries()
         val values = update(
             original,
@@ -683,6 +852,35 @@ class EventWriteMapperTest {
             instantAt("2026-07-01T09:00", "Europe/Berlin"),
             "TZID=Europe/Berlin;20260722T090000",
         )
+        // 22 July 09:00 Berlin (CEST, +2) == 07:00Z; the +1h edit puts it at 08:00Z.
+        assertThat(values[CalendarContract.Events.EXDATE]).isEqualTo("20260722T080000Z")
+    }
+
+    @Test
+    fun `a zoned list whose zone this device cannot place falls back to the event's`() {
+        // Exchange spells zones its own way, so ZoneId.of refuses the name. The
+        // series' own zone is what such a list is written in anyway.
+        val original = julySeries()
+        val values = update(
+            original,
+            original.atHour(10),
+            instantAt("2026-07-01T09:00", "Europe/Berlin"),
+            "TZID=W. Europe Standard Time;20260722T090000",
+        )
+        assertThat(values[CalendarContract.Events.EXDATE]).isEqualTo("20260722T080000Z")
+    }
+
+    @Test
+    fun `an exdate form we do not write is left untouched`() {
+        // A stale stamp excludes nothing; a mangled one could exclude the wrong
+        // occurrence, so anything unreadable is left exactly as it stands.
+        val original = julySeries()
+        val values = update(
+            original,
+            original.atHour(10),
+            instantAt("2026-07-01T09:00", "Europe/Berlin"),
+            "sometime next Tuesday",
+        )
         assertThat(values).doesNotContainKey(CalendarContract.Events.EXDATE)
     }
 
@@ -737,6 +935,7 @@ class EventWriteMapperTest {
                 existingExdate = "20260708T080000Z,20260715T080000Z,20260722T080000Z",
                 beginMillis = instantAt("2026-07-15T08:00", "UTC"),
                 isAllDay = false,
+                timezone = null,
             ),
         ).isEqualTo("20260722T080000Z")
     }
@@ -744,15 +943,25 @@ class EventWriteMapperTest {
     @Test
     fun `a split carries nothing when every exclusion is behind it`() {
         assertThat(
-            exdateAfter("20260708T080000Z", instantAt("2026-07-15T08:00", "UTC"), isAllDay = false),
+            exdateAfter(
+                "20260708T080000Z",
+                instantAt("2026-07-15T08:00", "UTC"),
+                isAllDay = false,
+                timezone = null,
+            ),
         ).isNull()
-        assertThat(exdateAfter(null, 0L, isAllDay = false)).isNull()
+        assertThat(exdateAfter(null, 0L, isAllDay = false, timezone = null)).isNull()
     }
 
     @Test
     fun `all-day exclusions split on their UTC date`() {
         assertThat(
-            exdateAfter("20260708,20260722", instantAt("2026-07-15T00:00", "UTC"), isAllDay = true),
+            exdateAfter(
+                "20260708,20260722",
+                instantAt("2026-07-15T00:00", "UTC"),
+                isAllDay = true,
+                timezone = null,
+            ),
         ).isEqualTo("20260722")
     }
 
@@ -760,13 +969,28 @@ class EventWriteMapperTest {
     fun `an unreadable exclusion carries nothing across a split`() {
         assertThat(
             exdateAfter(
-                "20260722T080000Z,TZID=Europe/Berlin;20260729T100000",
+                "20260722T080000Z,sometime next Tuesday",
                 instantAt("2026-07-15T08:00", "UTC"),
                 isAllDay = false,
+                timezone = null,
             ),
         ).isNull()
     }
 
+    @Test
+    fun `a zoned exclusion list splits on the instants its prefix names`() {
+        // Canonicalised on the way out: the prefix that explained how to read the
+        // stamps doesn't survive the filter, so the survivors can't stay floating.
+        assertThat(
+            exdateAfter(
+                "TZID=Europe/Berlin;20260708T100000,20260729T100000",
+                instantAt("2026-07-15T08:00", "UTC"),
+                isAllDay = false,
+                timezone = null,
+            ),
+        ).isEqualTo("20260729T080000Z")
+    }
+
     @Test
     fun `split exclusions move by the same shift as the new series start`() {
         // What the split path composes: filter to the tail, then re-time it by the
@@ -777,6 +1001,7 @@ class EventWriteMapperTest {
                 "20260716T070000Z",
                 instantAt("2026-07-15T07:00", "UTC"),
                 isAllDay = false,
+                timezone = null,
             ),
             original = original,
             updated = original.atHour(11),
@@ -980,4 +1205,173 @@ class EventWriteMapperTest {
         val values = buildCopiedExceptionValues(exceptionSnapshot(duration = "P900S", dtEndMillis = null))
         assertThat(values[CalendarContract.Events.DURATION]).isEqualTo("P900S")
     }
+
+    @Test
+    fun `a detached all-day occurrence matches its date-only exdate stamp`() {
+        val parent = buildOccurrenceExdateValues(
+            existingExdate = null,
+            occurrenceMillis = 1_781_136_000_000L, // 2026-06-11T00:00:00Z
+            dtStartMillis = 1_749_600_000_000L,
+            rrule = "FREQ=YEARLY",
+            rdate = null,
+            duration = "P1D",
+            timezone = "UTC",
+            allDay = 1,
+        )
+        val detached = form(
+            isAllDay = true,
+            start = LocalDateTime(LocalDate(2026, 6, 11), LocalTime(0, 0)),
+            end = LocalDateTime(LocalDate(2026, 6, 11), LocalTime(0, 0)),
+        ).copy(rrule = "FREQ=YEARLY").toDetachedOccurrence()
+        val inserted = buildEventInsertValues(
+            form = detached,
+            uid = "uid@calendula",
+            times = detached.toWriteTimes(berlin),
+        )
+        assertThat(parent[CalendarContract.Events.EXDATE]).isEqualTo("20260611")
+        assertThat(inserted[CalendarContract.Events.DTSTART]).isEqualTo(1_781_136_000_000L)
+    }
+
+    @Test
+    fun `a detached all-day occurrence stays on UTC midnights`() {
+        val edited = form(
+            isAllDay = true,
+            start = LocalDateTime(LocalDate(2026, 6, 11), LocalTime(0, 0)),
+            end = LocalDateTime(LocalDate(2026, 6, 11), LocalTime(0, 0)),
+        ).copy(title = "Birthday", rrule = "FREQ=YEARLY")
+        val detached = edited.toDetachedOccurrence()
+
+        val values = buildEventInsertValues(
+            form = detached,
+            uid = "uid@calendula",
+            times = detached.toWriteTimes(berlin),
+        )
+        assertThat(values[CalendarContract.Events.ALL_DAY]).isEqualTo(1)
+        assertThat(values[CalendarContract.Events.EVENT_TIMEZONE]).isEqualTo("UTC")
+        assertThat(values[CalendarContract.Events.DTSTART]).isEqualTo(1_781_136_000_000L)
+        // Exclusive DTEND — the next UTC midnight.
+        assertThat(values[CalendarContract.Events.DTEND]).isEqualTo(1_781_222_400_000L)
+        assertThat(values).doesNotContainKey(CalendarContract.Events.RRULE)
+    }
+
+    @Test
+    fun `a detached occurrence carries every edited field onto the new row`() {
+        // Built from the form, not cloned from the parent: a field dropped here
+        // is an edit silently lost.
+        val edited = form(timezone = "America/New_York").copy(
+            title = "  Standup  ",
+            location = "Room 2",
+            description = "notes",
+            reminders = listOf(10),
+            availability = Availability.Free,
+            accessLevel = AccessLevel.Private,
+            rrule = "FREQ=DAILY",
+        )
+        val detached = edited.toDetachedOccurrence()
+
+        val values = buildEventInsertValues(
+            form = detached,
+            uid = "uid@calendula",
+            times = detached.toWriteTimes(berlin),
+        )
+        assertThat(values[CalendarContract.Events.TITLE]).isEqualTo("Standup")
+        assertThat(values[CalendarContract.Events.EVENT_LOCATION]).isEqualTo("Room 2")
+        assertThat(values[CalendarContract.Events.DESCRIPTION]).isEqualTo("notes")
+        assertThat(values[CalendarContract.Events.AVAILABILITY])
+            .isEqualTo(CalendarContract.Events.AVAILABILITY_FREE)
+        assertThat(values[CalendarContract.Events.ACCESS_LEVEL])
+            .isEqualTo(CalendarContract.Events.ACCESS_PRIVATE)
+        // The pinned zone survives — never re-anchored to the device.
+        assertThat(values[CalendarContract.Events.EVENT_TIMEZONE]).isEqualTo("America/New_York")
+        assertThat(values[CalendarContract.Events.UID_2445]).isEqualTo("uid@calendula")
+        // Reminders aren't columns; the insert path seeds them from the form.
+        assertThat(detached.reminders).containsExactly(10)
+    }
+
+    @Test
+    fun `a detached occurrence drops the series rule and becomes a one-off row`() {
+        val edited = form().copy(title = "Moved", rrule = "FREQ=WEEKLY;BYDAY=TH")
+        val detached = edited.toDetachedOccurrence()
+
+        val values = buildEventInsertValues(
+            form = detached,
+            uid = "uid@calendula",
+            times = detached.toWriteTimes(berlin),
+        )
+        assertThat(values[CalendarContract.Events.TITLE]).isEqualTo("Moved")
+        // A surviving rule would insert a second *series* overlapping the first
+        // (Codeberg #234's stray duplicate).
+        assertThat(values).doesNotContainKey(CalendarContract.Events.RRULE)
+        assertThat(values).doesNotContainKey(CalendarContract.Events.DURATION)
+        // A one-off row carries DTEND rather than a duration.
+        assertThat(values[CalendarContract.Events.DTSTART]).isEqualTo(1_781_164_800_000L)
+        assertThat(values[CalendarContract.Events.DTEND]).isEqualTo(1_781_170_200_000L)
+        assertThat(values[CalendarContract.Events.EVENT_TIMEZONE]).isEqualTo("Europe/Berlin")
+    }
+
+    @Test
+    fun `an exclusion is found anywhere in a multi-entry exdate list`() {
+        // Whitespace after a comma is legal in the stored column.
+        assertThat(
+            exdateContains(
+                "20260604T080000Z, 20260611T080000Z,20260618T080000Z",
+                1_781_164_800_000L,
+                isAllDay = false,
+                timezone = null,
+            ),
+        ).isTrue()
+    }
+
+    @Test
+    fun `an occurrence already excluded is recognised, timed and all-day`() {
+        // Detaching twice would leave a second standalone copy.
+        assertThat(
+            exdateContains("20260611T080000Z", 1_781_164_800_000L, isAllDay = false, timezone = null),
+        ).isTrue()
+        assertThat(
+            exdateContains("20260611", 1_781_136_000_000L, isAllDay = true, timezone = null),
+        ).isTrue()
+    }
+
+    @Test
+    fun `an occurrence not in the exdate list is not mistaken for an excluded one`() {
+        assertThat(exdateContains(null, 1_781_164_800_000L, isAllDay = false, timezone = null))
+            .isFalse()
+        assertThat(exdateContains("", 1_781_164_800_000L, isAllDay = false, timezone = null))
+            .isFalse()
+        // A neighbouring occurrence must not match — the guard is per-instant.
+        assertThat(
+            exdateContains("20260610T080000Z", 1_781_164_800_000L, isAllDay = false, timezone = null),
+        ).isFalse()
+    }
+
+    @Test
+    fun `the detached row lands exactly where the parent's exdate removes it`() {
+        // The two halves must agree on the instant, or the user sees the
+        // occurrence twice or not at all.
+        val edited = form().copy(title = "Renamed", rrule = "FREQ=WEEKLY")
+        val occurrenceMillis = 1_781_164_800_000L
+
+        val parent = buildOccurrenceExdateValues(
+            existingExdate = null,
+            occurrenceMillis = occurrenceMillis,
+            dtStartMillis = 1_780_560_000_000L,
+            rrule = "FREQ=WEEKLY",
+            rdate = null,
+            duration = "P5400S",
+            timezone = "Europe/Berlin",
+            allDay = 0,
+        )
+        val detached = edited.toDetachedOccurrence()
+        val inserted = buildEventInsertValues(
+            form = detached,
+            uid = "uid@calendula",
+            times = detached.toWriteTimes(berlin),
+        )
+        assertThat(parent[CalendarContract.Events.EXDATE]).isEqualTo("20260611T080000Z")
+        assertThat(inserted[CalendarContract.Events.DTSTART]).isEqualTo(occurrenceMillis)
+        // The parent keeps its own anchor and rule — only this occurrence leaves.
+        assertThat(parent[CalendarContract.Events.DTSTART]).isEqualTo(1_780_560_000_000L)
+        assertThat(parent[CalendarContract.Events.RRULE]).isEqualTo("FREQ=WEEKLY")
+    }
 }

app/src/test/java/de/jeanlucmakiola/calendula/data/calendar/FakeCalendarDataSource.kt

@@ -23,6 +23,7 @@ internal class FakeCalendarDataSource : CalendarDataSource {
     var searchResult: (String) -> List<SearchCandidate> = { _ -> emptyList() }
     var eventDetailResult: (Long) -> EventDetail? = { null }
     var eventColorPaletteResult: (Long) -> List<EventColorOption> = { emptyList() }
+    var publishedEventColorsResult: (Long) -> List<EventColorOption> = { emptyList() }
     var exportableEventsResult: List<IcsEvent> = emptyList()
     /** The [calendarIds] the last [exportableEvents] call received (null = all). */
     var lastExportableEventsCalendarIds: Set<Long>? = null
@@ -81,7 +82,12 @@ internal class FakeCalendarDataSource : CalendarDataSource {
         eventDetailResult(eventId)
     override fun eventColorPalette(calendarId: Long): List<EventColorOption> =
         eventColorPaletteResult(calendarId)
-    override fun exportableEvents(calendarIds: Set<Long>?): List<IcsEvent> {
+    override fun publishedEventColors(calendarId: Long): List<EventColorOption> =
+        publishedEventColorsResult(calendarId)
+    override fun exportableEvents(
+        calendarIds: Set<Long>?,
+        allDayReminderTimeMinutes: Int,
+    ): List<IcsEvent> {
         lastExportableEventsCalendarIds = calendarIds
         return exportableEventsResult
     }
@@ -91,8 +97,25 @@ internal class FakeCalendarDataSource : CalendarDataSource {
     /** (event, targetCalendarId) pairs passed to [insertImportedEvent]. */
     val importedEvents = mutableListOf<Pair<ParsedIcsEvent, Long>>()
 
-    override fun insertImportedEvent(event: ParsedIcsEvent, calendarId: Long): Long {
-        writeError?.let { throw it }
+    /** Thrown instead of [writeError] for events whose summary is in this set. */
+    val failingImportSummaries = mutableSetOf<String>()
+
+    /** Imports let through before [writeError] applies, for part-way failures. */
+    var importsBeforeError: Int = 0
+    private var imports = 0
+
+    /** The [colorPalette] the last [insertImportedEvent] call received. */
+    var lastImportPalette: List<EventColorOption> = emptyList()
+
+    override fun insertImportedEvent(
+        event: ParsedIcsEvent,
+        calendarId: Long,
+        allDayReminderTimeMinutes: Int,
+        colorPalette: List<EventColorOption>,
+    ): Long {
+        lastImportPalette = colorPalette
+        if (imports++ >= importsBeforeError) writeError?.let { throw it }
+        if (event.summary in failingImportSummaries) error("rejected: ${event.summary}")
         importedEvents += event to calendarId
         return nextInsertId
     }
@@ -173,6 +196,7 @@ internal class FakeCalendarDataSource : CalendarDataSource {
     override fun updateOccurrence(
         eventId: Long,
         beginMillis: Long,
+        original: EventForm,
         form: EventForm,
         allDayReminderTimeMinutes: Int,
     ): Long {

app/src/test/java/de/jeanlucmakiola/calendula/data/calendar/IcsExportMapperTest.kt

@@ -4,6 +4,7 @@ import android.provider.CalendarContract
 import com.google.common.truth.Truth.assertThat
 import de.jeanlucmakiola.calendula.domain.EventStatus
 import org.junit.jupiter.api.Test
+import java.time.ZoneId
 
 class IcsExportMapperTest {
 
@@ -20,7 +21,11 @@ class IcsExportMapperTest {
             EventExportProjection.IDX_AVAILABILITY to CalendarContract.Events.AVAILABILITY_BUSY,
         )
 
-        val event = reader.toIcsEvent(reminderMinutes = listOf(10), calendarName = "Personal")
+        val event = reader.toIcsEvent(
+            reminderMinutes = listOf(10),
+            calendarName = "Personal",
+            allDayReminderTimeMinutes = NINE_AM,
+        )
 
         assertThat(event.uid).isEqualTo("abc@host")
         assertThat(event.summary).isEqualTo("Standup")
@@ -47,7 +52,11 @@ class IcsExportMapperTest {
             EventExportProjection.IDX_EVENT_TIMEZONE to "UTC",
         )
 
-        val event = reader.toIcsEvent(reminderMinutes = emptyList(), calendarName = null)
+        val event = reader.toIcsEvent(
+            reminderMinutes = emptyList(),
+            calendarName = null,
+            allDayReminderTimeMinutes = NINE_AM,
+        )
 
         assertThat(event.uid).isEqualTo("7-1000000@calendula")
         assertThat(event.recurrenceRule).isEqualTo("FREQ=WEEKLY")
@@ -65,6 +74,224 @@ class IcsExportMapperTest {
             EventExportProjection.IDX_EVENT_TIMEZONE to "UTC",
         )
 
-        assertThat(reader.toIcsEvent(emptyList(), null).isAllDay).isTrue()
+        assertThat(reader.toIcsEvent(emptyList(), null, NINE_AM).isAllDay).isTrue()
+    }
+
+    @Test
+    fun `an all-day reminder is exported as its whole-day lead time`() {
+        // The raw offset encodes the firing time and is normally negative; left
+        // raw it would be written as a trigger after the event and dropped, so
+        // the backup would come back with no reminder at all.
+        val reader = MapColumnReader(
+            EventExportProjection.IDX_ID to 1L,
+            EventExportProjection.IDX_TITLE to "Anna Birthday",
+            EventExportProjection.IDX_DTSTART to 1_782_864_000_000L, // 2026-07-01 UTC, CEST
+            EventExportProjection.IDX_DTEND to 1_782_950_400_000L,
+            EventExportProjection.IDX_ALL_DAY to 1,
+            EventExportProjection.IDX_EVENT_TIMEZONE to "UTC",
+        )
+
+        val onTheDay = reader.toIcsEvent(listOf(-420), null, NINE_AM, BERLIN)
+        val dayBefore = reader.toIcsEvent(listOf(1_020), null, NINE_AM, BERLIN)
+
+        assertThat(onTheDay.reminderMinutes).containsExactly(0)
+        assertThat(dayBefore.reminderMinutes).containsExactly(1_440)
+    }
+
+    private companion object {
+        const val NINE_AM = 9 * 60
+        val BERLIN: ZoneId = ZoneId.of("Europe/Berlin")
+    }
+
+    @Test
+    fun `a recurring row carries its EXDATE exclusions`() {
+        val reader = MapColumnReader(
+            EventExportProjection.IDX_ID to 7L,
+            EventExportProjection.IDX_TITLE to "Weekly",
+            EventExportProjection.IDX_DTSTART to 1_000_000L,
+            EventExportProjection.IDX_DURATION to "P3600S",
+            EventExportProjection.IDX_ALL_DAY to 0,
+            EventExportProjection.IDX_RRULE to "FREQ=WEEKLY",
+            EventExportProjection.IDX_EXDATE to "20260901T080000Z,20260908T080000Z",
+            EventExportProjection.IDX_EVENT_TIMEZONE to "UTC",
+        )
+
+        val event = reader.toIcsEvent(
+            reminderMinutes = emptyList(),
+            calendarName = null,
+            allDayReminderTimeMinutes = NINE_AM,
+        )
+
+        assertThat(event.exDates)
+            .containsExactly("20260901T080000Z", "20260908T080000Z").inOrder()
+    }
+
+    @Test
+    fun `an all-day EXDATE keeps only the day, however the adapter padded it`() {
+        val reader = MapColumnReader(
+            EventExportProjection.IDX_ID to 8L,
+            EventExportProjection.IDX_TITLE to "Holiday",
+            EventExportProjection.IDX_DTSTART to 0L,
+            EventExportProjection.IDX_DURATION to "P1D",
+            EventExportProjection.IDX_ALL_DAY to 1,
+            EventExportProjection.IDX_RRULE to "FREQ=YEARLY",
+            EventExportProjection.IDX_EXDATE to "20260901,20270901T000000Z",
+            EventExportProjection.IDX_EVENT_TIMEZONE to "UTC",
+        )
+
+        val event = reader.toIcsEvent(
+            reminderMinutes = emptyList(),
+            calendarName = null,
+            allDayReminderTimeMinutes = NINE_AM,
+        )
+
+        assertThat(event.exDates).containsExactly("20260901", "20270901").inOrder()
+    }
+
+    @Test
+    fun `a TZID-prefixed EXDATE is resolved to UTC, not handed on verbatim`() {
+        // The provider stores a zoned exclusion as AOSP RecurrenceSet does. Passed
+        // through, the writer would emit `EXDATE:TZID=Europe/Berlin;2026...` — the
+        // parameter belongs before the colon, so the line is unreadable.
+        val reader = MapColumnReader(
+            EventExportProjection.IDX_ID to 11L,
+            EventExportProjection.IDX_TITLE to "Weekly",
+            EventExportProjection.IDX_DTSTART to 1_000_000L,
+            EventExportProjection.IDX_DURATION to "P3600S",
+            EventExportProjection.IDX_ALL_DAY to 0,
+            EventExportProjection.IDX_RRULE to "FREQ=WEEKLY",
+            EventExportProjection.IDX_EXDATE to
+                "TZID=Europe/Berlin;20260722T090000,20260729T090000",
+            EventExportProjection.IDX_EVENT_TIMEZONE to "Europe/Berlin",
+        )
+
+        val event = reader.toIcsEvent(
+            reminderMinutes = emptyList(),
+            calendarName = null,
+            allDayReminderTimeMinutes = NINE_AM,
+        )
+
+        // 09:00 Berlin in July is CEST (+2) == 07:00Z.
+        assertThat(event.exDates)
+            .containsExactly("20260722T070000Z", "20260729T070000Z").inOrder()
+    }
+
+    @Test
+    fun `a zoned EXDATE in the provider's own bare form resolves in that zone`() {
+        // AOSP's RecurrenceSet stores the TZID parameter's value alone. Read as
+        // if it were unzoned, 09:00 Berlin exported as 09:00Z — two hours out,
+        // so the exclusion no longer matched its occurrence in the file.
+        val reader = MapColumnReader(
+            EventExportProjection.IDX_ID to 14L,
+            EventExportProjection.IDX_TITLE to "Weekly",
+            EventExportProjection.IDX_DTSTART to 1_000_000L,
+            EventExportProjection.IDX_DURATION to "P3600S",
+            EventExportProjection.IDX_ALL_DAY to 0,
+            EventExportProjection.IDX_RRULE to "FREQ=WEEKLY",
+            EventExportProjection.IDX_EXDATE to "Europe/Berlin;20260722T090000",
+            EventExportProjection.IDX_EVENT_TIMEZONE to "UTC",
+        )
+
+        val event = reader.toIcsEvent(
+            reminderMinutes = emptyList(),
+            calendarName = null,
+            allDayReminderTimeMinutes = NINE_AM,
+        )
+
+        assertThat(event.exDates).containsExactly("20260722T070000Z")
+    }
+
+    @Test
+    fun `a TZID this device cannot place falls back to the row's own zone`() {
+        // Exchange spells zones its own way, so ZoneId.of refuses the name.
+        // Stripping the prefix and emitting the stamp as it stands would export a
+        // floating time against a `DTSTART;TZID=…` line — every reader in another
+        // zone resolves it to another instant and the exclusion stops matching.
+        val reader = MapColumnReader(
+            EventExportProjection.IDX_ID to 13L,
+            EventExportProjection.IDX_TITLE to "Weekly",
+            EventExportProjection.IDX_DTSTART to 1_000_000L,
+            EventExportProjection.IDX_DURATION to "P3600S",
+            EventExportProjection.IDX_ALL_DAY to 0,
+            EventExportProjection.IDX_RRULE to "FREQ=WEEKLY",
+            EventExportProjection.IDX_EXDATE to
+                "TZID=W. Europe Standard Time;20260722T090000",
+            EventExportProjection.IDX_EVENT_TIMEZONE to "Europe/Berlin",
+        )
+
+        val event = reader.toIcsEvent(
+            reminderMinutes = emptyList(),
+            calendarName = null,
+            allDayReminderTimeMinutes = NINE_AM,
+        )
+
+        assertThat(event.exDates).containsExactly("20260722T070000Z")
+    }
+
+    @Test
+    fun `an all-day EXDATE loses a TZID prefix along with its time`() {
+        val reader = MapColumnReader(
+            EventExportProjection.IDX_ID to 12L,
+            EventExportProjection.IDX_TITLE to "Holiday",
+            EventExportProjection.IDX_DTSTART to 0L,
+            EventExportProjection.IDX_DURATION to "P1D",
+            EventExportProjection.IDX_ALL_DAY to 1,
+            EventExportProjection.IDX_RRULE to "FREQ=YEARLY",
+            EventExportProjection.IDX_EXDATE to "TZID=Europe/Berlin;20260901T000000",
+            EventExportProjection.IDX_EVENT_TIMEZONE to "Europe/Berlin",
+        )
+
+        val event = reader.toIcsEvent(
+            reminderMinutes = emptyList(),
+            calendarName = null,
+            allDayReminderTimeMinutes = NINE_AM,
+        )
+
+        assertThat(event.exDates).containsExactly("20260901")
+    }
+
+    @Test
+    fun `a default-lead all-day reminder is not decoded into an at-start alarm`() {
+        // MINUTES_DEFAULT (-1) says "use the account default", not "0 minutes
+        // before". Decoded, it landed on the start date and became a real alarm
+        // that IcsWriter no longer dropped.
+        val reader = MapColumnReader(
+            EventExportProjection.IDX_ID to 13L,
+            EventExportProjection.IDX_TITLE to "Birthday",
+            EventExportProjection.IDX_DTSTART to 0L,
+            EventExportProjection.IDX_DURATION to "P1D",
+            EventExportProjection.IDX_ALL_DAY to 1,
+            EventExportProjection.IDX_EVENT_TIMEZONE to "UTC",
+        )
+
+        val event = reader.toIcsEvent(
+            reminderMinutes = listOf(-1),
+            calendarName = null,
+            allDayReminderTimeMinutes = NINE_AM,
+            zone = BERLIN,
+        )
+
+        assertThat(event.reminderMinutes).containsExactly(-1)
+    }
+
+    @Test
+    fun `a one-off row exports no exclusions even if the column is set`() {
+        val reader = MapColumnReader(
+            EventExportProjection.IDX_ID to 9L,
+            EventExportProjection.IDX_TITLE to "Standup",
+            EventExportProjection.IDX_DTSTART to 1_000_000L,
+            EventExportProjection.IDX_DTEND to 1_900_000L,
+            EventExportProjection.IDX_ALL_DAY to 0,
+            EventExportProjection.IDX_EXDATE to "20260901T080000Z",
+            EventExportProjection.IDX_EVENT_TIMEZONE to "UTC",
+        )
+
+        val event = reader.toIcsEvent(
+            reminderMinutes = emptyList(),
+            calendarName = null,
+            allDayReminderTimeMinutes = NINE_AM,
+        )
+
+        assertThat(event.exDates).isEmpty()
     }
 }

app/src/test/java/de/jeanlucmakiola/calendula/data/calendar/ImportedEventValuesTest.kt

@@ -0,0 +1,119 @@
+package de.jeanlucmakiola.calendula.data.calendar
+
+import android.provider.CalendarContract
+import com.google.common.truth.Truth.assertThat
+import de.jeanlucmakiola.calendula.domain.EventColorOption
+import de.jeanlucmakiola.calendula.domain.ics.ParsedIcsEvent
+import org.junit.jupiter.api.Test
+import kotlin.time.Instant
+
+class ImportedEventValuesTest {
+
+    private val dayStart = Instant.parse("2026-08-19T00:00:00Z")
+
+    private fun allDay(
+        rrule: String? = null,
+        exDates: List<String> = emptyList(),
+        color: Int? = null,
+        days: Int = 1,
+    ) = ParsedIcsEvent(
+        uid = "u@x",
+        summary = "Anna Birthday",
+        start = dayStart,
+        end = Instant.fromEpochMilliseconds(dayStart.toEpochMilliseconds() + days * 86_400_000L),
+        isAllDay = true,
+        zoneId = "UTC",
+        recurrenceRule = rrule,
+        exDates = exDates,
+        color = color,
+    )
+
+    private fun values(event: ParsedIcsEvent, palette: List<EventColorOption> = emptyList()) =
+        buildImportedEventValues(event, calendarId = 7L, uid = "u@x", palette = palette)
+
+    @Test
+    fun `a one-off carries DTEND and no recurrence`() {
+        val v = values(allDay())
+        assertThat(v[CalendarContract.Events.DTEND])
+            .isEqualTo(dayStart.toEpochMilliseconds() + 86_400_000L)
+        assertThat(v).doesNotContainKey(CalendarContract.Events.DURATION)
+        assertThat(v[CalendarContract.Events.ALL_DAY]).isEqualTo(1)
+        assertThat(v[CalendarContract.Events.EVENT_TIMEZONE]).isEqualTo("UTC")
+    }
+
+    @Test
+    fun `a recurring row carries DURATION instead of DTEND`() {
+        val v = values(allDay(rrule = "FREQ=YEARLY;INTERVAL=1"))
+        assertThat(v).doesNotContainKey(CalendarContract.Events.DTEND)
+        assertThat(v[CalendarContract.Events.RRULE]).isEqualTo("FREQ=YEARLY;INTERVAL=1")
+        assertThat(v[CalendarContract.Events.DURATION]).isEqualTo("P1D")
+    }
+
+    @Test
+    fun `an all-day series is never zero days long`() {
+        // A degenerate span would expand into no instances at all — the series
+        // would simply not exist (Codeberg #225).
+        val v = values(allDay(rrule = "FREQ=YEARLY;INTERVAL=1", days = 0))
+        assertThat(v[CalendarContract.Events.DURATION]).isEqualTo("P1D")
+    }
+
+    @Test
+    fun `EXDATEs ride along with the recurrence`() {
+        val v = values(allDay(rrule = "FREQ=DAILY", exDates = listOf("20260820", "20260822")))
+        assertThat(v[CalendarContract.Events.EXDATE]).isEqualTo("20260820,20260822")
+    }
+
+    @Test
+    fun `EXDATEs are not written without a recurrence to exclude from`() {
+        val v = values(allDay(exDates = listOf("20260820")))
+        assertThat(v).doesNotContainKey(CalendarContract.Events.EXDATE)
+    }
+
+    @Test
+    fun `an imported colour is written raw when the account publishes no palette`() {
+        val v = values(allDay(color = -2818048))
+        assertThat(v[CalendarContract.Events.EVENT_COLOR]).isEqualTo(-2818048)
+        assertThat(v[CalendarContract.Events.EVENT_COLOR_KEY]).isNull()
+    }
+
+    @Test
+    fun `an imported colour snaps to the nearest published palette key`() {
+        val palette = listOf(
+            EventColorOption(key = "1", argb = 0xFF0000FF.toInt()), // blue
+            EventColorOption(key = "2", argb = 0xFFFF4500.toInt()), // orangered
+            EventColorOption(key = "3", argb = 0xFF008000.toInt()), // green
+        )
+        // Tomato — visually an orangered, nothing like the blue or the green.
+        val v = values(allDay(color = 0xFFFF6347.toInt()), palette)
+
+        assertThat(v[CalendarContract.Events.EVENT_COLOR_KEY]).isEqualTo("2")
+        // A raw colour alongside a key is what a palette calendar rejects.
+        assertThat(v).doesNotContainKey(CalendarContract.Events.EVENT_COLOR)
+    }
+
+    @Test
+    fun `an event with no colour touches neither colour column`() {
+        val v = values(allDay())
+        assertThat(v).doesNotContainKey(CalendarContract.Events.EVENT_COLOR)
+        assertThat(v).doesNotContainKey(CalendarContract.Events.EVENT_COLOR_KEY)
+    }
+
+    @Test
+    fun `a timed event keeps its own zone and a seconds duration`() {
+        val start = Instant.parse("2026-08-19T08:00:00Z")
+        val event = ParsedIcsEvent(
+            uid = "u@x",
+            summary = "Standup",
+            start = start,
+            end = Instant.parse("2026-08-19T08:15:00Z"),
+            isAllDay = false,
+            zoneId = "Europe/Berlin",
+            recurrenceRule = "FREQ=WEEKLY",
+        )
+
+        val v = values(event)
+        assertThat(v[CalendarContract.Events.EVENT_TIMEZONE]).isEqualTo("Europe/Berlin")
+        assertThat(v[CalendarContract.Events.DURATION]).isEqualTo("P900S")
+        assertThat(v[CalendarContract.Events.ALL_DAY]).isEqualTo(0)
+    }
+}

app/src/test/java/de/jeanlucmakiola/calendula/data/calendar/ProviderReminderMinutesTest.kt

@@ -0,0 +1,33 @@
+package de.jeanlucmakiola.calendula.data.calendar
+
+import com.google.common.truth.Truth.assertThat
+import org.junit.jupiter.api.Test
+
+/**
+ * The provider's "use the account default" sentinel is translated out here, so
+ * the pure planner only ever sees offsets it can resolve (#75).
+ */
+class ProviderReminderMinutesTest {
+
+    @Test
+    fun `the account-default sentinel is dropped`() {
+        // Taken as an offset it armed an alarm a minute *after* the event began,
+        // while the detail screen said "Default reminder" for the same row.
+        assertThat(mapOf(1L to listOf(-1)).withoutProviderDefaults())
+            .containsExactly(1L, emptyList<Int>())
+    }
+
+    @Test
+    fun `a real reminder beside a default one survives`() {
+        assertThat(mapOf(1L to listOf(-1, 10)).withoutProviderDefaults())
+            .containsExactly(1L, listOf(10))
+    }
+
+    @Test
+    fun `an all-day encoding that is negative is not mistaken for the sentinel`() {
+        // An all-day offset carries the firing time of day, so it is routinely
+        // negative; a `< 0` test would silence reminders that do fire.
+        assertThat(mapOf(1L to listOf(-420, -2_000)).withoutProviderDefaults())
+            .containsExactly(1L, listOf(-420, -2_000))
+    }
+}

app/src/test/java/de/jeanlucmakiola/calendula/domain/ics/IcsColorTest.kt

@@ -0,0 +1,40 @@
+package de.jeanlucmakiola.calendula.domain.ics
+
+import com.google.common.truth.Truth.assertThat
+import org.junit.jupiter.api.Test
+
+class IcsColorTest {
+
+    @Test
+    fun `a raw Android colour int round-trips`() {
+        assertThat(parseIcsColorValue("-2818048")).isEqualTo(-2818048)
+    }
+
+    @Test
+    fun `a CSS3 name resolves opaque`() {
+        assertThat(parseIcsColorValue("tomato")).isEqualTo(0xFFFF6347.toInt())
+        assertThat(parseIcsColorValue("REBECCAPURPLE")).isEqualTo(0xFF663399.toInt())
+    }
+
+    @Test
+    fun `hex forms are accepted with and without alpha`() {
+        assertThat(parseIcsColorValue("#ff6347")).isEqualTo(0xFFFF6347.toInt())
+        assertThat(parseIcsColorValue("#80ff6347")).isEqualTo(0x80FF6347.toInt())
+    }
+
+    @Test
+    fun `a colour with no alpha byte is made opaque`() {
+        // 0x00FF6347 as a decimal int — an RGB triple that lost its alpha.
+        assertThat(parseIcsColorValue("16737095")).isEqualTo(0xFFFF6347.toInt())
+    }
+
+    @Test
+    fun `unusable values resolve to null`() {
+        assertThat(parseIcsColorValue(null)).isNull()
+        assertThat(parseIcsColorValue("")).isNull()
+        // Fossify interpolates a nullable calendar straight into the property.
+        assertThat(parseIcsColorValue("null")).isNull()
+        assertThat(parseIcsColorValue("chartreusey")).isNull()
+        assertThat(parseIcsColorValue("#abc")).isNull()
+    }
+}

app/src/test/java/de/jeanlucmakiola/calendula/domain/ics/IcsFossifyImportTest.kt

@@ -0,0 +1,607 @@
+package de.jeanlucmakiola.calendula.domain.ics
+
+import com.google.common.truth.Truth.assertThat
+import kotlinx.datetime.TimeZone
+import org.junit.jupiter.api.Test
+import kotlin.time.Instant
+
+/**
+ * Reading the Simple Calendar / Fossify export dialect (Codeberg #225).
+ *
+ * Every fixture is shaped as `IcsExporter.writeEvent` emits it — property order,
+ * the `X-FOSSIFY-*` extensions and the `P0DT1H5M0S` duration spelling included.
+ *
+ * Their all-day `DTEND` is *usually* RFC-correct and must not be "corrected":
+ * `Event.endTS` anchors a UI-created all-day event at noon of its last day
+ * (`EventActivity.getStartEndTimes`), or at the exclusive midnight for a
+ * CalDAV-sourced one, and the exporter's `+ TWELVE_HOURS` rounds either to the
+ * following midnight. Shifting those by a day would corrupt them.
+ *
+ * The exception — and the whole of #225 — is events mirrored from Contacts.
+ * `MainActivity` builds those with `startTS = endTS = timestamp`, so `+ 12h`
+ * lands back on the starting day and they export zero length.
+ */
+class IcsFossifyImportTest {
+
+    private val parser = IcsParser(TimeZone.of("Europe/Berlin"))
+
+    private fun fossify(vararg body: String) = (
+        listOf(
+            "BEGIN:VCALENDAR",
+            "PRODID:-//Fossify//NONSGML Event Calendar//EN",
+            "VERSION:2.0",
+        ) + body + listOf("END:VCALENDAR")
+        ).joinToString("\r\n")
+
+    private fun days(event: ParsedIcsEvent): Long =
+        (event.end - event.start).inWholeMilliseconds / 86_400_000L
+
+    @Test
+    fun `an all-day event keeps the exact span the file gives it`() {
+        val result = parser.parse(
+            fossify(
+                "BEGIN:VEVENT",
+                "SUMMARY:Anna Birthday",
+                "UID:abc123",
+                "X-FOSSIFY-CATEGORY-COLOR:-1155931",
+                "DTSTART;VALUE=DATE:19900412",
+                "DTEND;VALUE=DATE:19900413",
+                "X-FOSSIFY-MISSING-YEAR:0",
+                "RRULE:FREQ=YEARLY;INTERVAL=1;BYMONTH=4",
+                "END:VEVENT",
+            ),
+        )
+
+        val event = result.events.single()
+        assertThat(event.isAllDay).isTrue()
+        assertThat(days(event)).isEqualTo(1)
+    }
+
+    @Test
+    fun `contact-mirrored birthdays export zero length and must not vanish`() {
+        // The reported failure (#225). Fossify mirrors Contacts birthdays and
+        // anniversaries with startTS == endTS, so the exporter's +12h rounds
+        // back to the starting day: DTSTART == DTEND. Read literally these are
+        // yearly series of zero-length occurrences, which the provider expands
+        // into nothing at all — the birthdays import "successfully" and are
+        // then nowhere to be seen.
+        val text = checkNotNull(
+            javaClass.classLoader?.getResourceAsStream("ics/fossify-contact-birthdays.ics"),
+        ).use { it.readBytes().toString(Charsets.UTF_8) }
+
+        val result = parser.parse(text)
+
+        assertThat(result.events).hasSize(3)
+        result.events.forEach {
+            assertThat(it.isAllDay).isTrue()
+            assertThat(days(it)).isEqualTo(1)
+            assertThat(it.recurrenceRule).startsWith("FREQ=YEARLY")
+            // Their all-day reminder encoding: "on the day", not midnight UTC.
+            assertThat(it.semanticReminderMinutes()).containsExactly(0)
+        }
+    }
+
+    @Test
+    fun `a real Fossify holiday file imports unchanged`() {
+        // Shipped inside Fossify Calendar (assets/holidays/AT/public.ics). Its
+        // PRODID names Fossify, so any producer-sniffing shortcut would corrupt
+        // it — the file is plain, conformant iCalendar.
+        val text = checkNotNull(
+            javaClass.classLoader?.getResourceAsStream("ics/fossify-holidays-at.ics"),
+        ).use { it.readBytes().toString(Charsets.UTF_8) }
+
+        val result = parser.parse(text)
+
+        assertThat(result.events.map { it.summary })
+            .containsExactly("Neujahr", "Heilige Drei Könige").inOrder()
+        assertThat(result.events.map { days(it) }).containsExactly(1L, 1L)
+        assertThat(result.events.map { it.recurrenceRule }).containsExactly("FREQ=YEARLY", "FREQ=YEARLY")
+    }
+
+    @Test
+    fun `an all-day event with no DTEND lasts one day`() {
+        // RFC 5545 3.6.1, and the span the provider needs to expand a series.
+        val result = parser.parse(
+            fossify(
+                "BEGIN:VEVENT",
+                "SUMMARY:Holiday",
+                "DTSTART;VALUE=DATE:20260819",
+                "END:VEVENT",
+            ),
+        )
+
+        assertThat(days(result.events.single())).isEqualTo(1)
+    }
+
+    @Test
+    fun `a zero-length all-day event is widened rather than left to vanish`() {
+        val result = parser.parse(
+            fossify(
+                "BEGIN:VEVENT",
+                "SUMMARY:Holiday",
+                "DTSTART;VALUE=DATE:20260819",
+                "DTEND;VALUE=DATE:20260819",
+                "END:VEVENT",
+            ),
+        )
+
+        assertThat(days(result.events.single())).isEqualTo(1)
+    }
+
+    @Test
+    fun `a malformed repeat rule is repaired rather than passed to the provider`() {
+        val result = parser.parse(
+            fossify(
+                "BEGIN:VEVENT",
+                "SUMMARY:Standup",
+                "DTSTART:20260819T080000Z",
+                "DTEND:20260819T081500Z",
+                "RRULE:FREQ=WEEKLY;INTERVAL=1;BYDAY=",
+                "END:VEVENT",
+            ),
+        )
+
+        assertThat(result.events.single().recurrenceRule).isEqualTo("FREQ=WEEKLY;INTERVAL=1")
+        assertThat(result.warnings).contains(IcsParseWarning.RecurrenceRuleRepaired)
+    }
+
+    @Test
+    fun `a task is imported as an event and reported`() {
+        val result = parser.parse(
+            fossify(
+                "BEGIN:VTODO",
+                "SUMMARY:Pay rent",
+                "DTSTART;VALUE=DATE:20260901",
+                "END:VTODO",
+            ),
+        )
+
+        val task = result.events.single()
+        assertThat(task.isTask).isTrue()
+        assertThat(task.summary).isEqualTo("Pay rent")
+        assertThat(days(task)).isEqualTo(1)
+        assertThat(result.warnings).contains(IcsParseWarning.TasksImportedAsEvents)
+    }
+
+    @Test
+    fun `a task dated only by DUE still imports`() {
+        val result = parser.parse(
+            fossify(
+                "BEGIN:VTODO",
+                "SUMMARY:File taxes",
+                "DUE;VALUE=DATE:20260901",
+                "END:VTODO",
+            ),
+        )
+
+        assertThat(result.events.single().summary).isEqualTo("File taxes")
+    }
+
+    @Test
+    fun `a task with both DTSTART and DUE spans between them`() {
+        val result = parser.parse(
+            fossify(
+                "BEGIN:VTODO",
+                "SUMMARY:Write report",
+                "DTSTART:20260901T090000Z",
+                "DUE:20260901T170000Z",
+                "END:VTODO",
+            ),
+        )
+
+        val task = result.events.single()
+        assertThat(task.start).isEqualTo(Instant.parse("2026-09-01T09:00:00Z"))
+        assertThat(task.end).isEqualTo(Instant.parse("2026-09-01T17:00:00Z"))
+    }
+
+    @Test
+    fun `a DUE ahead of the DTSTART is still the end`() {
+        // Property order isn't guaranteed; DUE must not be taken for the start.
+        val result = parser.parse(
+            fossify(
+                "BEGIN:VTODO",
+                "SUMMARY:Write report",
+                "DUE:20260901T170000Z",
+                "DTSTART:20260901T090000Z",
+                "END:VTODO",
+            ),
+        )
+
+        val task = result.events.single()
+        assertThat(task.start).isEqualTo(Instant.parse("2026-09-01T09:00:00Z"))
+        assertThat(task.end).isEqualTo(Instant.parse("2026-09-01T17:00:00Z"))
+    }
+
+    @Test
+    fun `the per-event colour wins over the calendar colour`() {
+        val result = parser.parse(
+            fossify(
+                "BEGIN:VEVENT",
+                "SUMMARY:Holiday",
+                "X-FOSSIFY-CATEGORY-COLOR:-1155931",
+                "COLOR:tomato",
+                "X-FOSSIFY-EVENT-COLOR:-2818048",
+                "DTSTART:20260819T080000Z",
+                "DTEND:20260819T090000Z",
+                "END:VEVENT",
+            ),
+        )
+
+        assertThat(result.events.single().color).isEqualTo(-2818048)
+    }
+
+    @Test
+    fun `the calendar colour stands in when the event has none of its own`() {
+        val result = parser.parse(
+            fossify(
+                "BEGIN:VEVENT",
+                "SUMMARY:Holiday",
+                "X-FOSSIFY-CATEGORY-COLOR:-1155931",
+                "DTSTART:20260819T080000Z",
+                "DTEND:20260819T090000Z",
+                "END:VEVENT",
+            ),
+        )
+
+        assertThat(result.events.single().color).isEqualTo(-1155931)
+    }
+
+    @Test
+    fun `the legacy Simple Calendar colour spellings are read too`() {
+        val result = parser.parse(
+            listOf(
+                "BEGIN:VCALENDAR",
+                "PRODID:-//Simple Mobile Tools//NONSGML Event Calendar//EN",
+                "BEGIN:VEVENT",
+                "SUMMARY:Holiday",
+                "X-SMT-CATEGORY-COLOR:-1155931",
+                "DTSTART:20260819T080000Z",
+                "DTEND:20260819T090000Z",
+                "END:VEVENT",
+                "END:VCALENDAR",
+            ).joinToString("\r\n"),
+        )
+
+        assertThat(result.events.single().color).isEqualTo(-1155931)
+    }
+
+    @Test
+    fun `the literal null Fossify writes for a missing calendar is not a colour`() {
+        // Both properties interpolate a nullable calendar straight into the value.
+        val result = parser.parse(
+            fossify(
+                "BEGIN:VEVENT",
+                "SUMMARY:Holiday",
+                "X-FOSSIFY-CATEGORY-COLOR:null",
+                "CATEGORIES:null",
+                "DTSTART:20260819T080000Z",
+                "DTEND:20260819T090000Z",
+                "END:VEVENT",
+            ),
+        )
+
+        val event = result.events.single()
+        assertThat(event.color).isNull()
+        assertThat(event.calendarName).isNull()
+    }
+
+    @Test
+    fun `CATEGORIES names the source calendar`() {
+        val result = parser.parse(
+            fossify(
+                "BEGIN:VEVENT",
+                "SUMMARY:Anna Birthday",
+                "CATEGORIES:Birthdays",
+                "DTSTART;VALUE=DATE:20260819",
+                "DTEND;VALUE=DATE:20260820",
+                "END:VEVENT",
+            ),
+        )
+
+        assertThat(result.events.single().calendarName).isEqualTo("Birthdays")
+    }
+
+    @Test
+    fun `CATEGORIES does not outrank a property that names the calendar outright`() {
+        // Elsewhere CATEGORIES is a tag list, so it only stands in where nothing
+        // else named the calendar — X-WR-CALNAME and our own label win.
+        val result = IcsParser().parse(
+            listOf(
+                "BEGIN:VCALENDAR",
+                "X-WR-CALNAME:Work",
+                "BEGIN:VEVENT",
+                "SUMMARY:Standup",
+                "CATEGORIES:Holiday",
+                "DTSTART:20260819T080000Z",
+                "DTEND:20260819T090000Z",
+                "END:VEVENT",
+                "END:VCALENDAR",
+            ).joinToString("\r\n"),
+        )
+
+        assertThat(result.events.single().calendarName).isEqualTo("Work")
+    }
+
+    @Test
+    fun `X-WR-CALNAME names the calendar wherever in the file it sits`() {
+        // Why the property is scanned up front instead of in document order: an
+        // exporter that writes it at the tail still names the calendar every
+        // event in the file came from.
+        val result = IcsParser().parse(
+            listOf(
+                "BEGIN:VCALENDAR",
+                "BEGIN:VEVENT",
+                "SUMMARY:Standup",
+                "DTSTART:20260819T080000Z",
+                "DTEND:20260819T090000Z",
+                "END:VEVENT",
+                "X-WR-CALNAME:Work",
+                "END:VCALENDAR",
+            ).joinToString("\r\n"),
+        )
+
+        assertThat(result.events.single().calendarName).isEqualTo("Work")
+    }
+
+    @Test
+    fun `a multi-valued CATEGORIES is a tag list, not a calendar name`() {
+        val result = parser.parse(
+            fossify(
+                "BEGIN:VEVENT",
+                "SUMMARY:Standup",
+                "CATEGORIES:Meeting,Personal",
+                "DTSTART:20260819T080000Z",
+                "DTEND:20260819T090000Z",
+                "END:VEVENT",
+            ),
+        )
+
+        assertThat(result.events.single().calendarName).isNull()
+    }
+
+    @Test
+    fun `a reminder written as a positive trigger is not read as a lead time`() {
+        // The exporter flips the sign for reminders stored below -1
+        // (`sign = if (reminder.minutes < -1) "" else "-"`), so a trigger can
+        // point after the start. On an all-day event that means a time of day.
+        val result = parser.parse(
+            fossify(
+                "BEGIN:VEVENT",
+                "SUMMARY:Anna Birthday",
+                "DTSTART;VALUE=DATE:20260819",
+                "DTEND;VALUE=DATE:20260820",
+                "BEGIN:VALARM",
+                "ACTION:DISPLAY",
+                "TRIGGER:P0DT9H0M0S",
+                "END:VALARM",
+                "END:VEVENT",
+            ),
+        )
+
+        val event = result.events.single()
+        assertThat(event.reminderMinutes).containsExactly(-540)
+        assertThat(event.semanticReminderMinutes()).containsExactly(0)
+    }
+
+    @Test
+    fun `an all-day reminder whose firing time is after noon keeps its full day`() {
+        // The raw offset is `days * 1440 - timeOfDay`, so an 18:00 notification
+        // time puts "1 day before" only six hours ahead of the UTC midnight.
+        // Rounding to the nearest day would read that as "on the day".
+        val result = parser.parse(
+            fossify(
+                "BEGIN:VEVENT",
+                "SUMMARY:Anna Birthday",
+                "DTSTART;VALUE=DATE:20260819",
+                "DTEND;VALUE=DATE:20260820",
+                "BEGIN:VALARM",
+                "ACTION:DISPLAY",
+                "TRIGGER:-P0DT6H0M0S",
+                "END:VALARM",
+                "END:VEVENT",
+            ),
+        )
+
+        assertThat(result.events.single().semanticReminderMinutes()).containsExactly(1440)
+    }
+
+    @Test
+    fun `an all-day reminder rounds to whole days before`() {
+        val result = parser.parse(
+            fossify(
+                "BEGIN:VEVENT",
+                "SUMMARY:Anna Birthday",
+                "DTSTART;VALUE=DATE:20260819",
+                "DTEND;VALUE=DATE:20260820",
+                "BEGIN:VALARM",
+                "ACTION:DISPLAY",
+                // 15h before midnight == "1 day before at 09:00".
+                "TRIGGER:-P0DT15H0M0S",
+                "END:VALARM",
+                "END:VEVENT",
+            ),
+        )
+
+        assertThat(result.events.single().semanticReminderMinutes()).containsExactly(1440)
+    }
+
+    @Test
+    fun `a timed reminder keeps its exact lead time`() {
+        // Their P0DT1H5M0S duration spelling, from Parser.getDurationCode.
+        val result = parser.parse(
+            fossify(
+                "BEGIN:VEVENT",
+                "SUMMARY:Standup",
+                "DTSTART:20260819T080000Z",
+                "DTEND:20260819T081500Z",
+                "BEGIN:VALARM",
+                "ACTION:DISPLAY",
+                "TRIGGER:-P0DT0H10M0S",
+                "END:VALARM",
+                "END:VEVENT",
+            ),
+        )
+
+        assertThat(result.events.single().semanticReminderMinutes()).containsExactly(10)
+    }
+
+    @Test
+    fun `a timed trigger that fires after the start is dropped, not clamped`() {
+        // A legal RFC 5545 follow-up alarm. Modelling it as a lead time of zero
+        // would invent a notification at the start the file never asked for.
+        val result = parser.parse(
+            fossify(
+                "BEGIN:VEVENT",
+                "SUMMARY:Standup",
+                "DTSTART:20260819T080000Z",
+                "DTEND:20260819T081500Z",
+                "BEGIN:VALARM",
+                "ACTION:DISPLAY",
+                "TRIGGER:PT30M",
+                "END:VALARM",
+                "END:VEVENT",
+            ),
+        )
+
+        assertThat(result.events.single().semanticReminderMinutes()).isEmpty()
+    }
+
+    @Test
+    fun `an all-day series' EXDATE day codes carry over`() {
+        val result = parser.parse(
+            fossify(
+                "BEGIN:VEVENT",
+                "SUMMARY:Standup",
+                "DTSTART;VALUE=DATE:20260819",
+                "DTEND;VALUE=DATE:20260820",
+                "RRULE:FREQ=DAILY;INTERVAL=1",
+                "EXDATE:20260820",
+                "EXDATE:20260822",
+                "END:VEVENT",
+            ),
+        )
+
+        assertThat(result.events.single().exDates).containsExactly("20260820", "20260822").inOrder()
+    }
+
+    @Test
+    fun `an all-day EXDATE keeps the day it spells out, whatever zone it carries`() {
+        // A midnight east of UTC resolves to an instant on the previous day;
+        // reading that back in UTC would exclude a day that isn't an occurrence
+        // and leave the one the user deleted in place.
+        val result = parser.parse(
+            fossify(
+                "BEGIN:VEVENT",
+                "SUMMARY:Standup",
+                "DTSTART;VALUE=DATE:20260819",
+                "DTEND;VALUE=DATE:20260820",
+                "RRULE:FREQ=DAILY",
+                "EXDATE;TZID=Europe/Berlin:20260821T000000",
+                "EXDATE;VALUE=DATE:20260823",
+                "END:VEVENT",
+            ),
+        )
+
+        assertThat(result.events.single().exDates)
+            .containsExactly("20260821", "20260823").inOrder()
+    }
+
+    @Test
+    fun `a timed series' bare EXDATE day code is resolved against the series time`() {
+        // They store excluded occurrences as day codes and write them out that
+        // way even for a timed series, where the property alone is ambiguous.
+        val result = parser.parse(
+            fossify(
+                "BEGIN:VEVENT",
+                "SUMMARY:Gym",
+                "DTSTART:20260819T170000Z",
+                "DTEND:20260819T180000Z",
+                "RRULE:FREQ=DAILY;INTERVAL=1",
+                "EXDATE:20260820",
+                "END:VEVENT",
+            ),
+        )
+
+        assertThat(result.events.single().exDates).containsExactly("20260820T170000Z")
+    }
+
+    @Test
+    fun `a floating EXDATE is read in the series' zone, not the device's`() {
+        // RFC 5545 ties EXDATE to DTSTART's form: with no Z and no TZID the
+        // value is New York wall time. Reading it in the device's Berlin zone
+        // would land on an instant no occurrence has, and the excluded
+        // occurrence would come back.
+        val result = parser.parse(
+            fossify(
+                "BEGIN:VEVENT",
+                "SUMMARY:Standup",
+                "DTSTART;TZID=America/New_York:20260819T100000",
+                "DTEND;TZID=America/New_York:20260819T103000",
+                "RRULE:FREQ=WEEKLY",
+                "EXDATE:20260826T100000",
+                "END:VEVENT",
+            ),
+        )
+
+        assertThat(result.events.single().exDates).containsExactly("20260826T140000Z")
+    }
+
+    @Test
+    fun `EXDATE is dropped along with an unusable recurrence rule`() {
+        val result = parser.parse(
+            fossify(
+                "BEGIN:VEVENT",
+                "SUMMARY:Gym",
+                "DTSTART:20260819T170000Z",
+                "DTEND:20260819T180000Z",
+                "RRULE:INTERVAL=1",
+                "EXDATE:20260820",
+                "END:VEVENT",
+            ),
+        )
+
+        val event = result.events.single()
+        assertThat(event.recurrenceRule).isNull()
+        assertThat(event.exDates).isEmpty()
+    }
+
+    @Test
+    fun `a whole export imports every component`() {
+        val result = parser.parse(
+            fossify(
+                "BEGIN:VEVENT",
+                "SUMMARY:Anna Birthday",
+                "UID:abc123",
+                "X-FOSSIFY-CATEGORY-COLOR:-1155931",
+                "CATEGORIES:Birthdays",
+                "LAST-MODIFIED:20260101T120000Z",
+                "TRANSP:TRANSPARENT",
+                "DTSTART;VALUE=DATE:19900412",
+                "DTEND;VALUE=DATE:19900413",
+                "X-FOSSIFY-MISSING-YEAR:0",
+                "DTSTAMP:20260819T100000Z",
+                "CLASS:PUBLIC",
+                "STATUS:CONFIRMED",
+                "RRULE:FREQ=YEARLY;INTERVAL=1;BYMONTH=4",
+                "END:VEVENT",
+                "BEGIN:VEVENT",
+                "SUMMARY:Standup",
+                "UID:def456",
+                "DTSTART:20260819T080000Z",
+                "DTEND:20260819T081500Z",
+                "RRULE:FREQ=WEEKLY;INTERVAL=1;BYDAY=TU",
+                "END:VEVENT",
+                "BEGIN:VTODO",
+                "SUMMARY:Pay rent",
+                "UID:ghi789",
+                "DTSTART;VALUE=DATE:20260901",
+                "END:VTODO",
+            ),
+        )
+
+        assertThat(result.events.map { it.summary })
+            .containsExactly("Anna Birthday", "Standup", "Pay rent").inOrder()
+        // Nothing may reach the provider as a zero-length all-day row.
+        assertThat(result.events.none { it.isAllDay && days(it) == 0L }).isTrue()
+    }
+}

app/src/test/java/de/jeanlucmakiola/calendula/domain/ics/IcsParserTest.kt

@@ -165,4 +165,36 @@ class IcsParserTest {
         assertThat(result.events.map { it.uid }).containsExactly("good")
         assertThat(result.warnings).contains(IcsParseWarning.EventWithoutStartSkipped)
     }
+
+    @Test
+    fun `round-trips a timed series' deleted occurrences`() {
+        val event = IcsEvent(
+            uid = "u20@calendula",
+            summary = "Weekly",
+            start = instantUtc(2026, 6, 18, 13, 0),
+            end = instantUtc(2026, 6, 18, 13, 30),
+            isAllDay = false,
+            zoneId = "UTC",
+            recurrenceRule = "FREQ=WEEKLY",
+            exDates = listOf("20260625T130000Z"),
+        )
+
+        assertThat(roundTrip(event).exDates).containsExactly("20260625T130000Z")
+    }
+
+    @Test
+    fun `round-trips an all-day series' deleted occurrences`() {
+        val event = IcsEvent(
+            uid = "u21@calendula",
+            summary = "Holiday",
+            start = LocalDate(2026, 6, 18).atStartOfDayIn(TimeZone.UTC),
+            end = LocalDate(2026, 6, 19).atStartOfDayIn(TimeZone.UTC),
+            isAllDay = true,
+            zoneId = "UTC",
+            recurrenceRule = "FREQ=YEARLY",
+            exDates = listOf("20270618"),
+        )
+
+        assertThat(roundTrip(event).exDates).containsExactly("20270618")
+    }
 }

app/src/test/java/de/jeanlucmakiola/calendula/domain/ics/IcsRecurrenceTest.kt

@@ -0,0 +1,166 @@
+package de.jeanlucmakiola.calendula.domain.ics
+
+import com.google.common.truth.Truth.assertThat
+import org.junit.jupiter.api.Test
+
+class IcsRecurrenceTest {
+
+    @Test
+    fun `a well-formed rule is unchanged`() {
+        val result = sanitizeRrule("FREQ=WEEKLY;INTERVAL=2;BYDAY=MO,WE")
+
+        assertThat(result.rule).isEqualTo("FREQ=WEEKLY;INTERVAL=2;BYDAY=MO,WE")
+        assertThat(result.repaired).isFalse()
+    }
+
+    @Test
+    fun `the RRULE prefix is stripped`() {
+        assertThat(sanitizeRrule("RRULE:FREQ=DAILY").rule).isEqualTo("FREQ=DAILY")
+    }
+
+    @Test
+    fun `an empty list part is dropped`() {
+        val bareByDay = sanitizeRrule("FREQ=WEEKLY;INTERVAL=1;BYDAY=")
+        assertThat(bareByDay.rule).isEqualTo("FREQ=WEEKLY;INTERVAL=1")
+        assertThat(bareByDay.repaired).isTrue()
+
+        assertThat(sanitizeRrule("FREQ=WEEKLY;BYDAY=MO,,WE;BYMONTH=").rule)
+            .isEqualTo("FREQ=WEEKLY;BYDAY=MO,WE")
+    }
+
+    @Test
+    fun `a nonsensical INTERVAL or COUNT is dropped, not fatal`() {
+        assertThat(sanitizeRrule("FREQ=DAILY;INTERVAL=0").rule).isEqualTo("FREQ=DAILY")
+        assertThat(sanitizeRrule("FREQ=DAILY;INTERVAL=every").rule).isEqualTo("FREQ=DAILY")
+        assertThat(sanitizeRrule("FREQ=DAILY;COUNT=0").rule).isEqualTo("FREQ=DAILY")
+    }
+
+    @Test
+    fun `a rule without a usable FREQ is unsalvageable`() {
+        assertThat(sanitizeRrule("INTERVAL=1;BYDAY=MO").rule).isNull()
+        assertThat(sanitizeRrule("FREQ=FORTNIGHTLY;INTERVAL=1").rule).isNull()
+        assertThat(sanitizeRrule("FREQ=;INTERVAL=1").rule).isNull()
+        assertThat(sanitizeRrule("").rule).isNull()
+        assertThat(sanitizeRrule(null).rule).isNull()
+    }
+
+    @Test
+    fun `no rule at all is not a repair`() {
+        assertThat(sanitizeRrule(null).repaired).isFalse()
+        assertThat(sanitizeRrule("").repaired).isFalse()
+        assertThat(sanitizeRrule("FREQ=FORTNIGHTLY").repaired).isTrue()
+    }
+
+    @Test
+    fun `normalising is not repairing`() {
+        // Case and a trailing separator change the text but lose nothing, and
+        // telling the user their file was faulty over either is crying wolf.
+        val lowercase = sanitizeRrule("freq=daily;count=3")
+        assertThat(lowercase.rule).isEqualTo("FREQ=DAILY;COUNT=3")
+        assertThat(lowercase.repaired).isFalse()
+
+        val trailing = sanitizeRrule("FREQ=DAILY;")
+        assertThat(trailing.rule).isEqualTo("FREQ=DAILY")
+        assertThat(trailing.repaired).isFalse()
+    }
+
+    @Test
+    fun `parts the provider's parser has no entry for are dropped`() {
+        // EventRecurrence.parse throws on any part name outside its own table,
+        // so passing one on would cost the whole event (Codeberg #225).
+        val result = sanitizeRrule("FREQ=MONTHLY;RSCALE=GREGORIAN;BYMONTHDAY=15")
+
+        assertThat(result.rule).isEqualTo("FREQ=MONTHLY;BYMONTHDAY=15")
+        assertThat(result.repaired).isTrue()
+        assertThat(sanitizeRrule("FREQ=YEARLY;X-THING=7").rule).isEqualTo("FREQ=YEARLY")
+    }
+
+    @Test
+    fun `WKST survives, a nonsense weekday does not`() {
+        assertThat(sanitizeRrule("FREQ=WEEKLY;WKST=SU").rule).isEqualTo("FREQ=WEEKLY;WKST=SU")
+        assertThat(sanitizeRrule("FREQ=WEEKLY;WKST=XX").rule).isEqualTo("FREQ=WEEKLY")
+    }
+
+    @Test
+    fun `a BYDAY item that isn't a weekday is dropped`() {
+        assertThat(sanitizeRrule("FREQ=MONTHLY;BYDAY=-1FR,1,MO").rule)
+            .isEqualTo("FREQ=MONTHLY;BYDAY=-1FR,MO")
+        assertThat(sanitizeRrule("FREQ=WEEKLY;BYDAY=mo,tu").rule)
+            .isEqualTo("FREQ=WEEKLY;BYDAY=MO,TU")
+    }
+
+    @Test
+    fun `a zero is dropped from the by-position parts only`() {
+        assertThat(sanitizeRrule("FREQ=MONTHLY;BYMONTHDAY=0,15").rule)
+            .isEqualTo("FREQ=MONTHLY;BYMONTHDAY=15")
+        assertThat(sanitizeRrule("FREQ=DAILY;BYHOUR=0,9").rule)
+            .isEqualTo("FREQ=DAILY;BYHOUR=0,9")
+    }
+
+    @Test
+    fun `an out-of-range numeric item is dropped`() {
+        // EventRecurrence.parseNumberList range-checks every one of these and
+        // throws out of insert, so being a number isn't enough (Codeberg #225).
+        assertThat(sanitizeRrule("FREQ=MONTHLY;BYMONTHDAY=15,32").rule)
+            .isEqualTo("FREQ=MONTHLY;BYMONTHDAY=15")
+        assertThat(sanitizeRrule("FREQ=DAILY;BYHOUR=25").rule).isEqualTo("FREQ=DAILY")
+        assertThat(sanitizeRrule("FREQ=YEARLY;BYMONTH=13").rule).isEqualTo("FREQ=YEARLY")
+        assertThat(sanitizeRrule("FREQ=YEARLY;BYWEEKNO=60").rule).isEqualTo("FREQ=YEARLY")
+        assertThat(sanitizeRrule("FREQ=YEARLY;BYYEARDAY=400").rule).isEqualTo("FREQ=YEARLY")
+        assertThat(sanitizeRrule("FREQ=DAILY;BYSECOND=60").rule).isEqualTo("FREQ=DAILY")
+        assertThat(sanitizeRrule("FREQ=DAILY;BYHOUR=25").repaired).isTrue()
+    }
+
+    @Test
+    fun `the edges of each range survive`() {
+        assertThat(sanitizeRrule("FREQ=MONTHLY;BYMONTHDAY=-31,31").repaired).isFalse()
+        assertThat(sanitizeRrule("FREQ=YEARLY;BYYEARDAY=-366,366;BYWEEKNO=-53,53").repaired)
+            .isFalse()
+        assertThat(sanitizeRrule("FREQ=DAILY;BYHOUR=23;BYMINUTE=59;BYSECOND=59").repaired)
+            .isFalse()
+        // BYSETPOS is the one part the provider leaves unbounded.
+        assertThat(sanitizeRrule("FREQ=MONTHLY;BYDAY=MO;BYSETPOS=-1,400").rule)
+            .isEqualTo("FREQ=MONTHLY;BYDAY=MO;BYSETPOS=-1,400")
+    }
+
+    @Test
+    fun `an UNTIL that isn't a timestamp is dropped`() {
+        assertThat(sanitizeRrule("FREQ=DAILY;UNTIL=20260819T235959Z").rule)
+            .isEqualTo("FREQ=DAILY;UNTIL=20260819T235959Z")
+        assertThat(sanitizeRrule("FREQ=DAILY;UNTIL=2026-08-19").rule).isEqualTo("FREQ=DAILY")
+    }
+
+    @Test
+    fun `UNTIL and COUNT together keep UNTIL`() {
+        // EventRecurrence.parse throws outright on a rule carrying both.
+        val both = sanitizeRrule("FREQ=WEEKLY;COUNT=10;UNTIL=20260101T000000Z")
+
+        assertThat(both.rule).isEqualTo("FREQ=WEEKLY;UNTIL=20260101T000000Z")
+        assertThat(both.repaired).isTrue()
+    }
+
+    @Test
+    fun `a COUNT the UNTIL check never sees is left alone`() {
+        // An UNTIL dropped for its shape doesn't take the COUNT down with it.
+        val staleUntil = sanitizeRrule("FREQ=WEEKLY;COUNT=10;UNTIL=2026-01-01")
+
+        assertThat(staleUntil.rule).isEqualTo("FREQ=WEEKLY;COUNT=10")
+        assertThat(staleUntil.repaired).isTrue()
+    }
+
+    @Test
+    fun `a part without a value separator is reported as repaired`() {
+        val noEquals = sanitizeRrule("FREQ=WEEKLY;BYDAY")
+
+        assertThat(noEquals.rule).isEqualTo("FREQ=WEEKLY")
+        assertThat(noEquals.repaired).isTrue()
+    }
+
+    @Test
+    fun `a trailing separator is normalisation, not a repair`() {
+        val trailing = sanitizeRrule("FREQ=DAILY;")
+
+        assertThat(trailing.rule).isEqualTo("FREQ=DAILY")
+        assertThat(trailing.repaired).isFalse()
+    }
+}

app/src/test/java/de/jeanlucmakiola/calendula/domain/ics/IcsWriterTest.kt

@@ -149,4 +149,55 @@ class IcsWriterTest {
         // Stable across calls — a re-export of the same row yields the same UID.
         assertThat(deriveIcsUid(null, 7, 1000)).isEqualTo(deriveIcsUid(null, 7, 1000))
     }
+
+    @Test
+    fun `a timed series writes its exclusions as UTC stamps`() {
+        val event = IcsEvent(
+            uid = "u9@calendula",
+            summary = "Weekly",
+            start = instantUtc(2026, 6, 18, 13, 0),
+            end = instantUtc(2026, 6, 18, 13, 30),
+            isAllDay = false,
+            zoneId = "UTC",
+            recurrenceRule = "FREQ=WEEKLY",
+            exDates = listOf("20260625T130000Z", "20260702T130000Z"),
+        )
+
+        assertThat(lines(listOf(event)))
+            .contains("EXDATE:20260625T130000Z,20260702T130000Z")
+    }
+
+    @Test
+    fun `an all-day series marks its exclusions VALUE=DATE`() {
+        val start = LocalDate(2026, 6, 18).atStartOfDayIn(TimeZone.UTC)
+        val event = IcsEvent(
+            uid = "u10@calendula",
+            summary = "Holiday",
+            start = start,
+            end = LocalDate(2026, 6, 19).atStartOfDayIn(TimeZone.UTC),
+            isAllDay = true,
+            zoneId = "UTC",
+            recurrenceRule = "FREQ=YEARLY",
+            exDates = listOf("20270618"),
+        )
+
+        // RFC 5545 ties EXDATE's value type to DTSTART's; a bare day code
+        // without VALUE=DATE reads as a malformed DATE-TIME.
+        assertThat(lines(listOf(event))).contains("EXDATE;VALUE=DATE:20270618")
+    }
+
+    @Test
+    fun `a one-off event never writes an EXDATE`() {
+        val event = IcsEvent(
+            uid = "u11@calendula",
+            summary = "Standup",
+            start = instantUtc(2026, 6, 18, 13, 0),
+            end = instantUtc(2026, 6, 18, 13, 30),
+            isAllDay = false,
+            zoneId = "UTC",
+            exDates = listOf("20260625T130000Z"),
+        )
+
+        assertThat(lines(listOf(event)).none { it.startsWith("EXDATE") }).isTrue()
+    }
 }

app/src/test/java/de/jeanlucmakiola/calendula/ui/common/RescheduleViewModelTest.kt

@@ -286,9 +286,53 @@ class RescheduleViewModelTest {
         vm.move(toWednesday())
         advanceUntilIdle()
 
+        val abandoned = vm.abandoned.value
         assertThat(vm.undo(undo)).isFalse()
         advanceUntilIdle()
         assertThat(fake.updatedEvents).hasSize(1)
+        // Nothing ticks: the refusal started no journey of its own, and the
+        // counter is global — a tick here would release the copy the drop that
+        // *is* in flight is holding, before the grid has drawn it.
+        assertThat(vm.abandoned.value).isEqualTo(abandoned)
+    }
+
+    @Test
+    fun `an undo that fails lets the held chip go`(@TempDir tempDir: Path) = runTest(dispatcher) {
+        // undoStarted has already sent the chip back on its journey by the time
+        // the inverse write is attempted. Without a tick here nothing ever seats
+        // it, and the overlay waits out its whole settle timeout for a chip that
+        // is never coming.
+        val fake = FakeCalendarDataSource().apply { eventDetailResult = { detail() } }
+        val vm = viewModel(tempDir, fake)
+        vm.move(oneHourLater())
+        advanceUntilIdle()
+        val undo = (vm.outcome.value as MoveOutcome.Moved).undo!!
+
+        val abandoned = vm.abandoned.value
+        fake.writeError = SecurityException("permission revoked")
+        assertThat(vm.undo(undo)).isTrue()
+        advanceUntilIdle()
+
+        assertThat(vm.outcome.value).isEqualTo(MoveOutcome.WriteDenied)
+        assertThat(vm.abandoned.value).isEqualTo(abandoned + 1)
+    }
+
+    @Test
+    fun `an undo that lands leaves the abandoned count alone`(
+        @TempDir tempDir: Path,
+    ) = runTest(dispatcher) {
+        val fake = FakeCalendarDataSource().apply { eventDetailResult = { detail() } }
+        val vm = viewModel(tempDir, fake)
+        vm.move(oneHourLater())
+        advanceUntilIdle()
+        val undo = (vm.outcome.value as MoveOutcome.Moved).undo!!
+
+        val abandoned = vm.abandoned.value
+        vm.undo(undo)
+        advanceUntilIdle()
+
+        assertThat(vm.outcome.value).isEqualTo(MoveOutcome.Undone)
+        assertThat(vm.abandoned.value).isEqualTo(abandoned)
     }
 
     @Test
@@ -494,4 +538,61 @@ class RescheduleViewModelTest {
         assertThat(fake.updatedEvents).isEmpty()
         assertThat(fake.updatedOccurrences).isEmpty()
     }
+
+    @Test
+    fun `a drop that lands nothing says so, since move() already answered yes`(
+        @TempDir tempDir: Path,
+    ) = runTest(dispatcher) {
+        val fake = FakeCalendarDataSource().apply { eventDetailResult = { detail() } }
+        val vm = viewModel(tempDir, fake)
+
+        // Refused in prepare: nowhere to move to.
+        assertThat(vm.move(
+            MoveRequest(
+                eventId = 42L,
+                beginMillis = beginMillis,
+                endMillis = endMillis,
+                target = MoveTarget.Start(Instant.fromEpochMilliseconds(beginMillis)),
+            ),
+        )).isTrue()
+        advanceUntilIdle()
+        assertThat(vm.abandoned.value).isEqualTo(1)
+
+        // Refused by the provider, after the write was attempted.
+        fake.writeError = SecurityException("revoked")
+        vm.move(oneHourLater())
+        advanceUntilIdle()
+        assertThat(vm.outcome.value).isEqualTo(MoveOutcome.WriteDenied)
+        assertThat(vm.abandoned.value).isEqualTo(2)
+    }
+
+    @Test
+    fun `a scope dialog dismissed leaves nothing waiting on the write`(
+        @TempDir tempDir: Path,
+    ) = runTest(dispatcher) {
+        val fake = FakeCalendarDataSource().apply {
+            eventDetailResult = { detail(rrule = "FREQ=WEEKLY") }
+        }
+        val vm = viewModel(tempDir, fake)
+
+        vm.move(oneHourLater())
+        advanceUntilIdle()
+        assertThat(vm.abandoned.value).isEqualTo(0)
+
+        vm.cancelScope()
+        advanceUntilIdle()
+        assertThat(vm.abandoned.value).isEqualTo(1)
+    }
+
+    @Test
+    fun `a written move never counts as abandoned`(@TempDir tempDir: Path) = runTest(dispatcher) {
+        val fake = FakeCalendarDataSource().apply { eventDetailResult = { detail() } }
+        val vm = viewModel(tempDir, fake)
+
+        vm.move(oneHourLater())
+        advanceUntilIdle()
+
+        assertThat(vm.outcome.value).isInstanceOf(MoveOutcome.Moved::class.java)
+        assertThat(vm.abandoned.value).isEqualTo(0)
+    }
 }

app/src/test/java/de/jeanlucmakiola/calendula/ui/common/TimedBlockShapeTest.kt

@@ -0,0 +1,209 @@
+package de.jeanlucmakiola.calendula.ui.common
+
+import com.google.common.truth.Truth.assertThat
+import de.jeanlucmakiola.calendula.domain.EventInstance
+import de.jeanlucmakiola.calendula.ui.week.MINUTES_PER_DAY
+import de.jeanlucmakiola.calendula.ui.week.layoutDay
+import kotlinx.datetime.DateTimeUnit
+import kotlinx.datetime.LocalDate
+import kotlinx.datetime.TimeZone
+import kotlinx.datetime.atTime
+import kotlinx.datetime.plus
+import kotlinx.datetime.toInstant
+import androidx.compose.foundation.shape.CornerSize
+import androidx.compose.ui.unit.dp
+import org.junit.jupiter.api.Test
+
+/**
+ * Which edges a timed block is cut on, and how much of a dragged piece its day
+ * can show (#253).
+ */
+class TimedBlockShapeTest {
+
+    private val zone = TimeZone.UTC
+    private val day1 = LocalDate(2026, 9, 5)
+    private val day2 = day1.plus(1, DateTimeUnit.DAY)
+    private val day3 = day2.plus(1, DateTimeUnit.DAY)
+
+    private fun event(from: LocalDateTimeIsh, to: LocalDateTimeIsh) = EventInstance(
+        instanceId = 1L, eventId = 1L, calendarId = 1L, title = "E",
+        start = from.date.atTime(from.hour, 0).toInstant(zone),
+        end = to.date.atTime(to.hour, 0).toInstant(zone),
+        isAllDay = false, color = 0xFF112233.toInt(), location = null,
+    )
+
+    data class LocalDateTimeIsh(val date: LocalDate, val hour: Int)
+
+    private fun at(date: LocalDate, hour: Int) = LocalDateTimeIsh(date, hour)
+
+    @Test
+    fun `a same-day block is cut on neither edge`() {
+        val ev = event(at(day1, 9), at(day1, 10))
+        val block = layoutDay(listOf(ev), day1, zone).single()
+
+        assertThat(block.continuesBefore(day1, zone)).isFalse()
+        assertThat(block.continuesAfter(day1, zone)).isFalse()
+    }
+
+    @Test
+    fun `an overnight event is cut at the foot of its first day and the head of its second`() {
+        val ev = event(at(day1, 20), at(day2, 8))
+
+        val head = layoutDay(listOf(ev), day1, zone).single()
+        assertThat(head.continuesBefore(day1, zone)).isFalse()
+        assertThat(head.continuesAfter(day1, zone)).isTrue()
+
+        val tail = layoutDay(listOf(ev), day2, zone).single()
+        assertThat(tail.continuesBefore(day2, zone)).isTrue()
+        assertThat(tail.continuesAfter(day2, zone)).isFalse()
+    }
+
+    @Test
+    fun `a day wholly inside a long event is cut on both edges`() {
+        val ev = event(at(day1, 20), at(day3, 8))
+        val middle = layoutDay(listOf(ev), day2, zone).single()
+
+        assertThat(middle.continuesBefore(day2, zone)).isTrue()
+        assertThat(middle.continuesAfter(day2, zone)).isTrue()
+    }
+
+    @Test
+    fun `an event ending exactly at midnight is not cut`() {
+        val ev = event(at(day1, 20), at(day2, 0))
+        val block = layoutDay(listOf(ev), day1, zone).single()
+
+        assertThat(block.continuesAfter(day1, zone)).isFalse()
+    }
+
+    @Test
+    fun `only the cut edges lose their corners`() {
+        val square = 0.dp
+        assertThat(timedBlockShape(continuesBefore = true, continuesAfter = false).topStart)
+            .isEqualTo(CornerSize(square))
+        assertThat(timedBlockShape(continuesBefore = true, continuesAfter = false).bottomStart)
+            .isEqualTo(CornerSize(EVENT_CHIP_CORNER))
+        assertThat(timedBlockShape(continuesBefore = false, continuesAfter = true).topStart)
+            .isEqualTo(CornerSize(EVENT_CHIP_CORNER))
+        assertThat(timedBlockShape(continuesBefore = false, continuesAfter = true).bottomEnd)
+            .isEqualTo(CornerSize(square))
+    }
+
+    private val fourHours = 4 * 60
+
+    @Test
+    fun `an event that fits its day is drawn as one uncut piece`() {
+        val pieces = dragSlices(eventStartMin = 10 * 60, spanMin = fourHours)
+
+        assertThat(pieces).hasSize(1)
+        assertThat(pieces.single().dayOffset).isEqualTo(0)
+        assertThat(pieces.single().spanMin).isEqualTo(fourHours)
+        assertThat(pieces.single().continuesBefore).isFalse()
+        assertThat(pieces.single().continuesAfter).isFalse()
+    }
+
+    @Test
+    fun `dragging the start half re-splits both days as it moves`() {
+        // Held at 22:00: two hours on this day, two on the next.
+        assertThat(dragSlices(22 * 60, fourHours).map { it.spanMin })
+            .containsExactly(2 * 60, 2 * 60).inOrder()
+        // Carried up to 21:00 the first day takes three, so the second day's end
+        // comes up by exactly the hour the first day gained.
+        assertThat(dragSlices(21 * 60, fourHours).map { it.spanMin })
+            .containsExactly(3 * 60, 60).inOrder()
+    }
+
+    @Test
+    fun `dragging the end half splits the same way, one day back`() {
+        // The tail's top edge is at midnight and the event began two hours
+        // earlier, so it starts at -120 relative to the day the finger is on.
+        val pieces = dragSlices(eventStartMin = -2 * 60, spanMin = fourHours)
+
+        assertThat(pieces.map { it.dayOffset }).containsExactly(-1, 0).inOrder()
+        assertThat(pieces.map { it.spanMin }).containsExactly(2 * 60, 2 * 60).inOrder()
+        // The piece on the earlier day ends at midnight; the held one starts there.
+        assertThat(pieces.first().startMin).isEqualTo(22 * 60)
+        assertThat(pieces.first().continuesAfter).isTrue()
+        assertThat(pieces.last().startMin).isEqualTo(0)
+        assertThat(pieces.last().continuesBefore).isTrue()
+    }
+
+    @Test
+    fun `the earlier half shrinks away as the end half is pulled down its own day`() {
+        // Tail top dragged from midnight down to 01:00: one hour left behind.
+        assertThat(dragSlices(-2 * 60 + 60, fourHours).map { it.spanMin })
+            .containsExactly(60, 3 * 60).inOrder()
+        // At 02:00 the event no longer crosses midnight at all.
+        val whole = dragSlices(0, fourHours)
+        assertThat(whole).hasSize(1)
+        assertThat(whole.single().continuesBefore).isFalse()
+    }
+
+    @Test
+    fun `a day wholly inside a long event is cut on both sides`() {
+        val pieces = dragSlices(eventStartMin = 22 * 60, spanMin = 30 * 60)
+
+        assertThat(pieces.map { it.dayOffset }).containsExactly(0, 1, 2).inOrder()
+        assertThat(pieces[1].spanMin).isEqualTo(MINUTES_PER_DAY)
+        assertThat(pieces[1].continuesBefore).isTrue()
+        assertThat(pieces[1].continuesAfter).isTrue()
+    }
+
+    @Test
+    fun `an event ending exactly at midnight takes no piece of the next day`() {
+        val pieces = dragSlices(eventStartMin = 22 * 60, spanMin = 2 * 60)
+
+        assertThat(pieces).hasSize(1)
+        assertThat(pieces.single().continuesAfter).isFalse()
+    }
+
+    @Test
+    fun `a zero-length event still has a piece to draw`() {
+        val pieces = dragSlices(eventStartMin = 9 * 60, spanMin = 0)
+
+        assertThat(pieces).hasSize(1)
+        assertThat(pieces.single().dayOffset).isEqualTo(0)
+        assertThat(pieces.single().startMin).isEqualTo(9 * 60)
+        assertThat(pieces.single().spanMin).isEqualTo(0)
+    }
+
+    @Test
+    fun `only the days there are columns for are sliced`() {
+        // A week's worth of event, previewed on a timeline showing three days
+        // from the one the finger is on.
+        val pieces = dragSlices(0, 7 * MINUTES_PER_DAY, within = 0..2)
+
+        assertThat(pieces.map { it.dayOffset }).containsExactly(0, 1, 2).inOrder()
+        assertThat(pieces.last().continuesAfter).isTrue()
+    }
+
+    @Test
+    fun `an event outside the columns shown is sliced into nothing`() {
+        assertThat(dragSlices(-3 * MINUTES_PER_DAY, 60, within = 0..2)).isEmpty()
+    }
+
+    // --- the copy never blinks out from under the finger (#253) ---
+
+    @Test
+    fun `a short tail dragged to its floor still has a piece to draw`() {
+        // 23:50-00:05: on the tail's day the clip offset is 10 and the floor is
+        // one snap step above midnight, which puts the whole event on the day
+        // before. Day view has no column for that day, so dragSlices hands back
+        // nothing and the floating copy used to vanish mid-gesture.
+        val span = 15
+        val floor = dragFloorMin(clipOffsetMin = 10, eventSpanMin = span)
+        val eventStartMin = floor - 10
+        val visible = 0..0
+
+        assertThat(dragSlices(eventStartMin, span, visible)).isEmpty()
+        val edge = edgeDragSlice(eventStartMin, span, visible)
+        assertThat(edge).isNotNull()
+        assertThat(edge!!.dayOffset).isEqualTo(0)
+        assertThat(edge.startMin).isEqualTo(0)
+        assertThat(edge.continuesBefore).isTrue()
+    }
+
+    @Test
+    fun `an event a visible column does hold gets no edge piece`() {
+        assertThat(edgeDragSlice(9 * 60, 60, 0..0)).isNull()
+    }
+}

app/src/test/java/de/jeanlucmakiola/calendula/ui/common/TimelineDropTest.kt

@@ -0,0 +1,156 @@
+package de.jeanlucmakiola.calendula.ui.common
+
+import com.google.common.truth.Truth.assertThat
+import de.jeanlucmakiola.calendula.domain.EventInstance
+import de.jeanlucmakiola.calendula.ui.week.TimedBlock
+import de.jeanlucmakiola.calendula.ui.week.layoutDay
+import kotlinx.datetime.DateTimeUnit
+import kotlinx.datetime.LocalDate
+import kotlinx.datetime.TimeZone
+import kotlinx.datetime.atTime
+import kotlinx.datetime.plus
+import kotlinx.datetime.toInstant
+import org.junit.jupiter.api.Test
+
+/**
+ * What a timeline drop asks for, for the head and the tail of an event that
+ * crosses midnight (#253). The tail's top edge is midnight rather than the
+ * event's start, so the drop has to take that offset back off.
+ */
+class TimelineDropTest {
+
+    private val zone = TimeZone.UTC
+    private val sat = LocalDate(2026, 9, 5)
+    private val sun = sat.plus(1, DateTimeUnit.DAY)
+
+    // Sat 5 Sep 20:00 to Sun 6 Sep 08:00.
+    private val overnight = EventInstance(
+        instanceId = 1L,
+        eventId = 1L,
+        calendarId = 1L,
+        title = "Night shift",
+        start = sat.atTime(20, 0).toInstant(zone),
+        end = sun.atTime(8, 0).toInstant(zone),
+        isAllDay = false,
+        color = 0xFF112233.toInt(),
+        location = null,
+    )
+
+    private fun blockOn(day: LocalDate): TimedBlock =
+        layoutDay(listOf(overnight), day, zone).single()
+
+    @Test
+    fun `the head block carries no clip offset`() {
+        val head = blockOn(sat)
+        assertThat(head.startMin).isEqualTo(20 * 60)
+        assertThat(head.clipOffsetMinutes(sat, zone)).isEqualTo(0)
+    }
+
+    @Test
+    fun `the tail block is offset by the part that already ran`() {
+        val tail = blockOn(sun)
+        assertThat(tail.startMin).isEqualTo(0)
+        // 20:00 to midnight is four hours of the event already gone.
+        assertThat(tail.clipOffsetMinutes(sun, zone)).isEqualTo(4 * 60)
+    }
+
+    @Test
+    fun `dropping the head asks for exactly where it landed`() {
+        val target = LocalDate(2026, 9, 2)
+        val drop = TimelineDrop(overnight, target, 20 * 60, clipOffsetMin = 0)
+
+        assertThat(drop.startInstant(zone)).isEqualTo(target.atTime(20, 0).toInstant(zone))
+    }
+
+    @Test
+    fun `dropping the tail moves the event by the days the tail travelled`() {
+        val tail = blockOn(sun)
+        val offset = tail.clipOffsetMinutes(sun, zone)
+        // Dragged three days back, same height in the column: Sun 6 -> Thu 3.
+        val drop = TimelineDrop(overnight, LocalDate(2026, 9, 3), 0, offset)
+
+        // The event began Sat 5 Sep 20:00, so it now begins Wed 2 Sep 20:00 —
+        // the whole event moved three days, and no time of day was invented.
+        assertThat(drop.startInstant(zone))
+            .isEqualTo(LocalDate(2026, 9, 2).atTime(20, 0).toInstant(zone))
+    }
+
+    @Test
+    fun `dragging the tail down the column re-times the event across midnight`() {
+        val offset = blockOn(sun).clipOffsetMinutes(sun, zone)
+        // Tail top pulled from 00:00 to 03:00 on its own day.
+        val drop = TimelineDrop(overnight, sun, 3 * 60, offset)
+
+        assertThat(drop.startInstant(zone)).isEqualTo(sat.atTime(23, 0).toInstant(zone))
+    }
+
+    @Test
+    fun `pulling the tail above its own midnight moves the event earlier`() {
+        val offset = blockOn(sun).clipOffsetMinutes(sun, zone)
+        // The tail's top edge dragged an hour above the midnight it rests on.
+        val drop = TimelineDrop(overnight, sun, -60, offset)
+
+        // Event was Sat 20:00 to Sun 08:00; it now begins an hour earlier.
+        assertThat(drop.startInstant(zone)).isEqualTo(sat.atTime(19, 0).toInstant(zone))
+    }
+
+    @Test
+    fun `a top edge dragged past the next midnight resolves onto the day after`() {
+        val drop = TimelineDrop(overnight, sat, 25 * 60, clipOffsetMin = 0)
+
+        assertThat(drop.startInstant(zone)).isEqualTo(sun.atTime(1, 0).toInstant(zone))
+    }
+
+    @Test
+    fun `a short tail can still be dragged a step earlier`() {
+        // 23:50 to 00:05: five minutes of tail, less than one snap step, which
+        // a floor pinned at midnight left with nowhere to go (#253).
+        assertThat(dragFloorMin(clipOffsetMin = 10, eventSpanMin = 15))
+            .isEqualTo(-DRAG_SNAP_MINUTES)
+    }
+
+    @Test
+    fun `a long tail may rise until its event ends just inside the day`() {
+        // Sat 20:00 to Sun 08:00, held by the Sunday half.
+        assertThat(dragFloorMin(clipOffsetMin = 4 * 60, eventSpanMin = 12 * 60))
+            .isEqualTo(DRAG_SNAP_MINUTES - 8 * 60)
+    }
+
+    @Test
+    fun `an unclipped block cannot be dragged above its own midnight`() {
+        assertThat(dragFloorMin(clipOffsetMin = 0, eventSpanMin = 60)).isEqualTo(0)
+    }
+
+    @Test
+    fun `a drop across a DST boundary keeps the time of day it was let go at`() {
+        // Europe/Berlin springs forward at 02:00 on 29 March 2026, between the
+        // event's start and the midnight its tail is cut at.
+        val berlin = TimeZone.of("Europe/Berlin")
+        val sun = LocalDate(2026, 3, 29)
+        val overnightIntoDst = EventInstance(
+            instanceId = 3L, eventId = 3L, calendarId = 1L, title = "Night shift",
+            start = LocalDate(2026, 3, 28).atTime(22, 0).toInstant(berlin),
+            end = sun.atTime(6, 0).toInstant(berlin),
+            isAllDay = false, color = 0xFF112233.toInt(), location = null,
+        )
+        val tail = layoutDay(listOf(overnightIntoDst), sun, berlin).single()
+        val offset = tail.clipOffsetMinutes(sun, berlin)
+        // Dropped back onto its own slot a week earlier, clear of the boundary.
+        val drop = TimelineDrop(overnightIntoDst, LocalDate(2026, 3, 22), 0, offset)
+
+        assertThat(drop.startInstant(berlin))
+            .isEqualTo(LocalDate(2026, 3, 21).atTime(22, 0).toInstant(berlin))
+    }
+
+    @Test
+    fun `a block that is not clipped is unaffected wherever it sits`() {
+        val plain = EventInstance(
+            instanceId = 2L, eventId = 2L, calendarId = 1L, title = "Standup",
+            start = sat.atTime(9, 0).toInstant(zone),
+            end = sat.atTime(10, 0).toInstant(zone),
+            isAllDay = false, color = 0xFF112233.toInt(), location = null,
+        )
+        val block = layoutDay(listOf(plain), sat, zone).single()
+        assertThat(block.clipOffsetMinutes(sat, zone)).isEqualTo(0)
+    }
+}

app/src/test/java/de/jeanlucmakiola/calendula/ui/imports/ImportTargetTest.kt

@@ -0,0 +1,89 @@
+package de.jeanlucmakiola.calendula.ui.imports
+
+import com.google.common.truth.Truth.assertThat
+import de.jeanlucmakiola.calendula.domain.CalendarSource
+import de.jeanlucmakiola.calendula.domain.ics.ParsedIcsEvent
+import org.junit.jupiter.api.Test
+import kotlin.time.Instant
+
+/** Which calendar a bulk import lands on before the user touches the picker. */
+class ImportTargetTest {
+
+    private fun cal(id: Long, name: String, local: Boolean = false) = CalendarSource(
+        id = id,
+        displayName = name,
+        accountName = "acc@local",
+        accountType = if (local) "LOCAL" else "com.google",
+        color = 0,
+        isVisibleInSystem = true,
+        isLocal = local,
+    )
+
+    private val calendars = listOf(
+        cal(1L, "Work"),
+        cal(2L, "Personal", local = true),
+        cal(3L, "Birthdays", local = true),
+    )
+
+    @Test
+    fun `a calendar named like the file's wins`() {
+        assertThat(defaultImportTarget(calendars, "Birthdays")).isEqualTo(3L)
+    }
+
+    @Test
+    fun `the name match ignores case`() {
+        assertThat(defaultImportTarget(calendars, "birthdays")).isEqualTo(3L)
+    }
+
+    @Test
+    fun `an unmatched name falls back to the first local calendar`() {
+        assertThat(defaultImportTarget(calendars, "Holidays")).isEqualTo(2L)
+    }
+
+    @Test
+    fun `no name at all falls back to the first local calendar`() {
+        assertThat(defaultImportTarget(calendars, null)).isEqualTo(2L)
+    }
+
+    @Test
+    fun `with no local calendars the first of any kind is taken`() {
+        assertThat(defaultImportTarget(listOf(cal(1L, "Work")), null)).isEqualTo(1L)
+    }
+
+    @Test
+    fun `an empty list preselects nothing`() {
+        assertThat(defaultImportTarget(emptyList(), "Birthdays")).isNull()
+    }
+
+    private fun event(calendarName: String?) = ParsedIcsEvent(
+        uid = "u@x",
+        summary = "E",
+        start = Instant.fromEpochMilliseconds(0L),
+        end = Instant.fromEpochMilliseconds(3_600_000L),
+        isAllDay = false,
+        zoneId = "UTC",
+        calendarName = calendarName,
+    )
+
+    @Test
+    fun `a file whose events all name one calendar names it`() {
+        assertThat(fileCalendarName(List(3) { event("Birthdays") })).isEqualTo("Birthdays")
+    }
+
+    @Test
+    fun `disagreeing events name none`() {
+        assertThat(fileCalendarName(listOf(event("Birthdays"), event("Anniversaries")))).isNull()
+    }
+
+    @Test
+    fun `one tagged event among unnamed ones names none`() {
+        // CATEGORIES is a tag list everywhere but the Fossify family, so a lone
+        // tagged event must not decide where the whole file lands.
+        assertThat(fileCalendarName(listOf(event("Holiday")) + List(9) { event(null) })).isNull()
+    }
+
+    @Test
+    fun `a file that names nothing names none`() {
+        assertThat(fileCalendarName(List(3) { event(null) })).isNull()
+    }
+}

app/src/test/java/de/jeanlucmakiola/calendula/ui/month/ChipSeatTest.kt

@@ -0,0 +1,120 @@
+package de.jeanlucmakiola.calendula.ui.month
+
+import com.google.common.truth.Truth.assertThat
+import de.jeanlucmakiola.calendula.domain.EventInstance
+import kotlinx.datetime.DateTimeUnit
+import kotlinx.datetime.LocalDate
+import kotlinx.datetime.atTime
+import kotlinx.datetime.plus
+import kotlinx.datetime.TimeZone
+import kotlinx.datetime.toInstant
+import org.junit.jupiter.api.Test
+
+/**
+ * Where a week row draws a moved chip — what the settling copy glides onto
+ * (#68, #253).
+ */
+class ChipSeatTest {
+
+    private val monday = LocalDate(2026, 6, 8)
+    private val days = (0..6).map { monday.plus(it, DateTimeUnit.DAY) }
+
+    private fun event(id: Long, title: String = "E") = EventInstance(
+        instanceId = id,
+        eventId = id,
+        calendarId = 1L,
+        title = title,
+        start = monday.atTime(9, 0).toInstant(TimeZone.UTC),
+        end = monday.atTime(10, 0).toInstant(TimeZone.UTC),
+        isAllDay = false,
+        color = 0xFF112233.toInt(),
+        location = null,
+    )
+
+    /**
+     * A grid holding [seated] in lane 0 as one bar across [cols], and nothing
+     * else — the seating a [MonthWeek] gives a span.
+     */
+    private fun row(seated: EventInstance, cols: IntRange) = MonthWeek(
+        days = days,
+        spans = listOf(
+            MonthSpan(
+                event = seated,
+                startCol = cols.first,
+                endCol = cols.last,
+                lane = 0,
+                continuesLeft = false,
+                continuesRight = false,
+            ),
+        ),
+        timedByDay = emptyMap(),
+        countByDay = emptyMap(),
+    )
+
+    /** A grid holding one single-day pill per day of [cols], all of [seated]. */
+    private fun pills(seated: EventInstance, cols: IntRange) = MonthWeek(
+        days = days,
+        spans = emptyList(),
+        timedByDay = cols.associate { days[it] to listOf(seated) },
+        countByDay = emptyMap(),
+    )
+
+    private fun seat(week: MonthWeek, event: EventInstance, date: LocalDate) = chipSeat(
+        days = days,
+        laneCount = 3,
+        chipAt = { col, lane -> week.chipAt(col, lane, 3) },
+        chipStart = { col, lane -> week.chipStartCol(col, lane) },
+        event = event,
+        date = date,
+    )
+
+    @Test
+    fun `a single-day chip is seated in its own column`() {
+        val ev = event(1L)
+        assertThat(seat(row(ev, 3..3), ev, days[3])).isEqualTo(3 to 0)
+    }
+
+    @Test
+    fun `a bar is seated from its first column, not the day it was dropped on`() {
+        val ev = event(1L)
+        // Covers Wed–Thu; dropped on the Thursday it now runs into.
+        assertThat(seat(row(ev, 2..3), ev, days[3])).isEqualTo(2 to 0)
+    }
+
+    @Test
+    fun `a bar carried in from the previous week is seated at column zero`() {
+        val ev = event(1L)
+        assertThat(seat(row(ev, 0..4), ev, days[4])).isEqualTo(0 to 0)
+    }
+
+    @Test
+    fun `a row that does not hold the event seats nothing`() {
+        val ev = event(1L)
+        assertThat(seat(row(ev, 2..3), ev, days[5])).isNull()
+        assertThat(seat(row(ev, 2..3), ev, LocalDate(2026, 7, 1))).isNull()
+    }
+
+    @Test
+    fun `a re-read chip is matched by title once its event id has changed`() {
+        // A single-occurrence move writes a new event id; the title survives.
+        val moved = event(1L, title = "Standup")
+        val reRead = event(9L, title = "Standup")
+        assertThat(seat(row(reRead, 3..3), moved, days[3])).isEqualTo(3 to 0)
+    }
+
+    @Test
+    fun `two untitled events are not the same event`() {
+        val moved = event(1L, title = "")
+        val other = event(2L, title = "")
+        assertThat(isSameEvent(other, moved)).isFalse()
+        assertThat(seat(row(other, 3..3), moved, days[3])).isNull()
+    }
+
+    @Test
+    fun `a daily series seats each occurrence in its own column`() {
+        // Every column holds an occurrence of the same event id, so a walk left
+        // by identity would run to the start of the row (#253).
+        val ev = event(1L, title = "Standup")
+        assertThat(seat(pills(ev, 0..6), ev, days[4])).isEqualTo(4 to 0)
+    }
+}

app/src/test/java/de/jeanlucmakiola/calendula/ui/month/MonthLayoutTest.kt

@@ -44,6 +44,19 @@ class MonthLayoutTest {
         location = null,
     )
 
+    /** A timed event running from [date] 20:00 into the next day at [endHour]. */
+    private fun overnight(date: LocalDate, endHour: Int = 8) = EventInstance(
+        instanceId = 7L,
+        eventId = 7L,
+        calendarId = 1L,
+        title = "Night shift",
+        start = at(date, 20),
+        end = at(date.plus(1, DateTimeUnit.DAY), endHour),
+        isAllDay = false,
+        color = 0xFF112233.toInt(),
+        location = null,
+    )
+
     /** All-day events live at UTC midnights with an *exclusive* end. */
     private fun allDay(
         from: LocalDate,
@@ -162,6 +175,43 @@ class MonthLayoutTest {
         assertThat(week.timedByDay[LocalDate(2026, 6, 11)]).isEmpty()
     }
 
+    @Test
+    fun `an event crossing midnight is one bar, not two pills, on both sides of a week seam`() {
+        // Sun 14 Jun 20:00 to Mon 15 Jun 08:00 — the seam of a Monday-anchored
+        // grid: one day in this row, one in the next. Counting per row made each
+        // a standalone pill with nothing saying they were one event (#253).
+        val overnight = overnight(LocalDate(2026, 6, 14))
+        val head = layoutCalendarWeek(weekOf8th, listOf(overnight), zone)
+        assertThat(head.timedByDay.values.flatten()).isEmpty()
+        val headSpan = head.spans.single()
+        assertThat(headSpan.startCol).isEqualTo(6)
+        assertThat(headSpan.endCol).isEqualTo(6)
+        assertThat(headSpan.continuesLeft).isFalse()
+        assertThat(headSpan.continuesRight).isTrue()
+
+        val tailRow = layoutCalendarWeek(
+            weekOf8th.map { it.plus(7, DateTimeUnit.DAY) },
+            listOf(overnight),
+            zone,
+        )
+        assertThat(tailRow.timedByDay.values.flatten()).isEmpty()
+        val tailSpan = tailRow.spans.single()
+        assertThat(tailSpan.startCol).isEqualTo(0)
+        assertThat(tailSpan.endCol).isEqualTo(0)
+        assertThat(tailSpan.continuesLeft).isTrue()
+        assertThat(tailSpan.continuesRight).isFalse()
+    }
+
+    @Test
+    fun `an event ending exactly at midnight stays a single-day pill`() {
+        val untilMidnight = overnight(LocalDate(2026, 6, 10), endHour = 0)
+        val week = layoutCalendarWeek(weekOf8th, listOf(untilMidnight), zone)
+
+        assertThat(week.spans).isEmpty()
+        assertThat(week.timedByDay[LocalDate(2026, 6, 10)]).hasSize(1)
+        assertThat(week.timedByDay[LocalDate(2026, 6, 11)]).isEmpty()
+    }
+
     @Test
     fun `countByDay totals bars and pills on each date`() {
         val span = allDay(LocalDate(2026, 6, 10), LocalDate(2026, 6, 12), id = 1L)

app/src/test/java/de/jeanlucmakiola/calendula/widget/WidgetRolloverSchedulerTest.kt

@@ -0,0 +1,189 @@
+package de.jeanlucmakiola.calendula.widget
+
+import android.content.Intent
+import com.google.common.truth.Truth.assertThat
+import kotlinx.datetime.LocalDate
+import kotlinx.datetime.LocalDateTime
+import kotlinx.datetime.TimeZone
+import kotlinx.datetime.atStartOfDayIn
+import kotlinx.datetime.toInstant
+import kotlinx.datetime.toLocalDateTime
+import org.junit.jupiter.api.Test
+import kotlin.time.Duration
+import kotlin.time.Duration.Companion.hours
+import kotlin.time.Duration.Companion.minutes
+import kotlin.time.Instant
+
+/**
+ * The rollover alarm is what makes the widgets stop highlighting yesterday
+ * (#228), so the "when is the next local midnight" arithmetic is the one piece
+ * worth pinning down — especially where midnight is not 00:00.
+ */
+class WidgetRolloverSchedulerTest {
+
+    private val berlin = TimeZone.of("Europe/Berlin")
+
+    private fun at(local: String, zone: TimeZone): Instant =
+        LocalDateTime.parse(local).toInstant(zone)
+
+    private fun nextRollover(local: String, zone: TimeZone = berlin): Instant =
+        WidgetRolloverScheduler.nextRolloverAt(at(local, zone), zone)
+
+    // --- the ordinary day ----------------------------------------------------
+
+    @Test
+    fun `midday rolls over at the coming midnight`() {
+        val next = nextRollover("2026-08-27T12:00:00")
+        assertThat(next).isEqualTo(at("2026-08-28T00:00:05", berlin))
+    }
+
+    @Test
+    fun `a second before midnight still targets tonight, not tomorrow night`() {
+        val next = nextRollover("2026-08-27T23:59:59")
+        assertThat(next).isEqualTo(at("2026-08-28T00:00:05", berlin))
+    }
+
+    @Test
+    fun `at midnight exactly the target is the next day, never the current instant`() {
+        // Re-arming after a firing must move a whole day on, or the widget wakes
+        // itself in a tight loop.
+        val now = at("2026-08-28T00:00:00", berlin)
+        val next = WidgetRolloverScheduler.nextRolloverAt(now, berlin)
+        assertThat(next).isEqualTo(at("2026-08-29T00:00:05", berlin))
+        assertThat(next - now).isGreaterThan(Duration.ZERO)
+    }
+
+    @Test
+    fun `re-arming from the slack instant itself moves a full day on`() {
+        // What actually happens in practice: the receiver runs at midnight + slack.
+        val now = at("2026-08-28T00:00:05", berlin)
+        assertThat(WidgetRolloverScheduler.nextRolloverAt(now, berlin))
+            .isEqualTo(at("2026-08-29T00:00:05", berlin))
+    }
+
+    @Test
+    fun `the result is always in the future for every minute of a day`() {
+        val zone = berlin
+        // Spans Berlin's 2024 spring-forward: the likeliest source of a target
+        // in the past, i.e. an alarm that fires immediately, forever.
+        var probe = LocalDateTime.parse("2024-03-29T00:00:00").toInstant(zone)
+        val end = LocalDateTime.parse("2024-04-01T00:00:00").toInstant(zone)
+        while (probe < end) {
+            assertThat(WidgetRolloverScheduler.nextRolloverAt(probe, zone)).isGreaterThan(probe)
+            probe += 1.minutes
+        }
+    }
+
+    // --- daylight saving -----------------------------------------------------
+
+    @Test
+    fun `spring forward keeps the rollover one day away, not one hour short`() {
+        // Berlin skipped 02:00-03:00 on 31 March 2024, so that day was 23h long.
+        // A rollover computed as "now + 24h" would land at 01:00 on 1 April.
+        val now = at("2024-03-30T12:00:00", berlin)
+        val next = WidgetRolloverScheduler.nextRolloverAt(now, berlin)
+        assertThat(next).isEqualTo(at("2024-03-31T00:00:05", berlin))
+        assertThat(next - now).isLessThan(24.hours)
+    }
+
+    @Test
+    fun `fall back does not overshoot into the repeated hour`() {
+        // Berlin repeated 02:00-03:00 on 27 October 2024: a 25h day, so
+        // "now + 24h" would land at 23:00 on the 26th and never roll over.
+        val now = at("2024-10-26T12:00:00", berlin)
+        val next = WidgetRolloverScheduler.nextRolloverAt(now, berlin)
+        assertThat(next).isEqualTo(at("2024-10-27T00:00:05", berlin))
+        assertThat(next.toLocalDateTime(berlin).date).isEqualTo(LocalDate.parse("2024-10-27"))
+    }
+
+    @Test
+    fun `a zone that repeats midnight takes the first start of day`() {
+        // Sao Paulo used to end DST by moving 00:00 back to 23:00, so the day
+        // began twice. Pinned as the accepted trade: the widget runs an hour
+        // ahead until the next redraw. No live zone does this since 2019.
+        val saoPaulo = TimeZone.of("America/Sao_Paulo")
+        val next = WidgetRolloverScheduler.nextRolloverAt(
+            at("2018-02-16T12:00:00", saoPaulo), saoPaulo,
+        )
+        val local = next.toLocalDateTime(saoPaulo)
+        assertThat(local.date).isEqualTo(LocalDate.parse("2018-02-17"))
+        assertThat(local.hour).isEqualTo(0)
+    }
+
+    @Test
+    fun `a zone where midnight does not exist rolls over at the real start of day`() {
+        // Cuba starts DST at 00:00, so 11 March 2018 began at 01:00 in Havana.
+        // Targeting a literal 00:00 there would arm an instant on the wrong day.
+        val havana = TimeZone.of("America/Havana")
+        val next = WidgetRolloverScheduler.nextRolloverAt(at("2018-03-10T12:00:00", havana), havana)
+        val local = next.toLocalDateTime(havana)
+        assertThat(local.date).isEqualTo(LocalDate.parse("2018-03-11"))
+        assertThat(local.hour).isEqualTo(1)
+        assertThat(local.minute).isEqualTo(0)
+        // And it is genuinely the first instant of that date, not a guess.
+        assertThat(next).isEqualTo(
+            LocalDate.parse("2018-03-11").atStartOfDayIn(havana) +
+                WidgetRolloverScheduler.ROLLOVER_SLACK,
+        )
+    }
+
+    // --- timezone changes ----------------------------------------------------
+
+    @Test
+    fun `the same instant rolls over at different times in different zones`() {
+        // TIMEZONE_CHANGED must re-arm to the new local midnight: the arithmetic
+        // follows the zone, not a cached offset.
+        val instant = at("2026-08-27T12:00:00", berlin)
+        val tokyo = TimeZone.of("Asia/Tokyo")
+        val berlinNext = WidgetRolloverScheduler.nextRolloverAt(instant, berlin)
+        val tokyoNext = WidgetRolloverScheduler.nextRolloverAt(instant, tokyo)
+        assertThat(tokyoNext).isNotEqualTo(berlinNext)
+        assertThat(tokyoNext).isLessThan(berlinNext)
+        assertThat(tokyoNext.toLocalDateTime(tokyo).hour).isEqualTo(0)
+    }
+
+    @Test
+    fun `a half-hour offset zone still lands on its own midnight`() {
+        val kathmandu = TimeZone.of("Asia/Kathmandu")
+        val next = WidgetRolloverScheduler.nextRolloverAt(
+            at("2026-08-27T12:00:00", kathmandu), kathmandu,
+        )
+        val local = next.toLocalDateTime(kathmandu)
+        assertThat(local.date.toString()).isEqualTo("2026-08-28")
+        assertThat(local.hour).isEqualTo(0)
+    }
+
+    // --- the wiring ----------------------------------------------------------
+
+    @Test
+    fun `the receiver actually handles the action the alarm is sent with`() {
+        // The single point where the whole fix would die silently: the alarm
+        // fires, the receiver drops it on the action guard, nothing redraws.
+        assertThat(WidgetUpdateReceiver.HANDLED_ACTIONS)
+            .contains(WidgetUpdateReceiver.ACTION_ROLLOVER)
+    }
+
+    @Test
+    fun `a data change is handled, and re-arms only on the throttle`() {
+        // PROVIDER_CHANGED fires on every calendar write — each event of a bulk
+        // import, each drop of a drag — so it is not an unconditional re-arm.
+        // It is not dropped either: the alarm is inexact and the system may lose
+        // it, and this is the only signal that keeps arriving to notice.
+        assertThat(WidgetUpdateReceiver.HANDLED_ACTIONS)
+            .containsAtLeast(Intent.ACTION_PROVIDER_CHANGED, Intent.ACTION_DATE_CHANGED)
+        assertThat(WidgetUpdateReceiver.REARM_ACTIONS)
+            .doesNotContain(Intent.ACTION_PROVIDER_CHANGED)
+    }
+
+    @Test
+    fun `everything that loses the alarm re-arms it`() {
+        assertThat(WidgetUpdateReceiver.REARM_ACTIONS).containsAtLeast(
+            WidgetUpdateReceiver.ACTION_ROLLOVER,
+            Intent.ACTION_BOOT_COMPLETED,
+            Intent.ACTION_MY_PACKAGE_REPLACED,
+            Intent.ACTION_TIME_CHANGED,
+            Intent.ACTION_TIMEZONE_CHANGED,
+            Intent.ACTION_DATE_CHANGED,
+        )
+    }
+}

app/src/test/resources/ics/fossify-contact-birthdays.ics

@@ -0,0 +1,64 @@
+BEGIN:VCALENDAR
+PRODID:-//Fossify//NONSGML Event Calendar//EN
+VERSION:2.0
+BEGIN:VEVENT
+SUMMARY:Anna Schmidt
+UID:101
+X-FOSSIFY-CATEGORY-COLOR:-1155931
+CATEGORIES:Birthdays
+LAST-MODIFIED:20250615T150640Z
+TRANSP:TRANSPARENT
+DTSTART;VALUE=DATE:19900412
+DTEND;VALUE=DATE:19900412
+X-FOSSIFY-MISSING-YEAR:0
+DTSTAMP:20260819T120000Z
+CLASS:PUBLIC
+STATUS:CONFIRMED
+RRULE:FREQ=YEARLY;INTERVAL=1;BYMONTH=4
+BEGIN:VALARM
+DESCRIPTION:Reminder
+ACTION:DISPLAY
+TRIGGER:P0DT9H0M0S
+END:VALARM
+END:VEVENT
+BEGIN:VEVENT
+SUMMARY:Opa
+UID:102
+X-FOSSIFY-CATEGORY-COLOR:-1155931
+CATEGORIES:Birthdays
+LAST-MODIFIED:20250615T150640Z
+TRANSP:TRANSPARENT
+DTSTART;VALUE=DATE:19700603
+DTEND;VALUE=DATE:19700603
+X-FOSSIFY-MISSING-YEAR:1
+DTSTAMP:20260819T120000Z
+CLASS:PUBLIC
+STATUS:CONFIRMED
+RRULE:FREQ=YEARLY;INTERVAL=1;BYMONTH=6
+BEGIN:VALARM
+DESCRIPTION:Reminder
+ACTION:DISPLAY
+TRIGGER:P0DT9H0M0S
+END:VALARM
+END:VEVENT
+BEGIN:VEVENT
+SUMMARY:Hochzeitstag
+UID:103
+X-FOSSIFY-CATEGORY-COLOR:-1155931
+CATEGORIES:Anniversaries
+LAST-MODIFIED:20250615T150640Z
+TRANSP:TRANSPARENT
+DTSTART;VALUE=DATE:20050917
+DTEND;VALUE=DATE:20050917
+X-FOSSIFY-MISSING-YEAR:0
+DTSTAMP:20260819T120000Z
+CLASS:PUBLIC
+STATUS:CONFIRMED
+RRULE:FREQ=YEARLY;INTERVAL=1;BYMONTH=9
+BEGIN:VALARM
+DESCRIPTION:Reminder
+ACTION:DISPLAY
+TRIGGER:P0DT9H0M0S
+END:VALARM
+END:VEVENT
+END:VCALENDAR

app/src/test/resources/ics/fossify-holidays-at.ics

@@ -0,0 +1,25 @@
+BEGIN:VCALENDAR
+VERSION:2.0
+CALSCALE:GREGORIAN
+PRODID:Fossify Calendar Holiday Generator
+METHOD:PUBLISH
+X-PUBLISHED-TTL:PT1H
+BEGIN:VEVENT
+UID:fossify_c10f9ad245dc2e57fb3652abee6ed8a06744f0bd
+SUMMARY:Neujahr
+DTSTAMP:20260526T132315Z
+DTSTART;VALUE=DATE:19800101
+DTEND;VALUE=DATE:19800102
+STATUS:CONFIRMED
+RRULE:FREQ=YEARLY
+END:VEVENT
+BEGIN:VEVENT
+UID:fossify_8a60ccf65b65265f768dd33a0b7aefc7620e3ee2
+SUMMARY:Heilige Drei Könige
+DTSTAMP:20260526T132315Z
+DTSTART;VALUE=DATE:19800106
+DTEND;VALUE=DATE:19800107
+STATUS:CONFIRMED
+RRULE:FREQ=YEARLY
+END:VEVENT
+END:VCALENDAR