test: cover the export calendar-id plumbing

The fake now records the calendarIds it receives; two repository tests
assert exportEvents forwards a chosen subset and defaults to null (all
eligible calendars), closing the coverage gap for the per-calendar
export selector.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

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

@@ -536,6 +536,30 @@ class CalendarRepositoryImplTest {
         assertThat(fake.importedEvents.map { it.second }).containsExactly(3L, 3L)
     }
 
+    @Test
+    fun `exportEvents forwards the chosen calendar-id subset to the data source`(
+        @TempDir tempDir: Path,
+    ) = runTest {
+        val fake = FakeCalendarDataSource()
+        val repo = CalendarRepositoryImpl(fake, newPrefs(tempDir), newSettings(tempDir), Dispatchers.Unconfined)
+
+        repo.exportEvents(calendarIds = setOf(1L, 4L))
+
+        assertThat(fake.lastExportableEventsCalendarIds).containsExactly(1L, 4L)
+    }
+
+    @Test
+    fun `exportEvents defaults to null so every eligible calendar is exported`(
+        @TempDir tempDir: Path,
+    ) = runTest {
+        val fake = FakeCalendarDataSource()
+        val repo = CalendarRepositoryImpl(fake, newPrefs(tempDir), newSettings(tempDir), Dispatchers.Unconfined)
+
+        repo.exportEvents()
+
+        assertThat(fake.lastExportableEventsCalendarIds).isNull()
+    }
+
     private fun parsedEvent(uid: String?) = de.jeanlucmakiola.calendula.domain.ics.ParsedIcsEvent(
         uid = uid,
         summary = "E",

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

@@ -23,6 +23,8 @@ internal class FakeCalendarDataSource : CalendarDataSource {
     var eventDetailResult: (Long) -> EventDetail? = { null }
     var eventColorPaletteResult: (Long) -> List<EventColorOption> = { emptyList() }
     var exportableEventsResult: List<IcsEvent> = emptyList()
+    /** The [calendarIds] the last [exportableEvents] call received (null = all). */
+    var lastExportableEventsCalendarIds: Set<Long>? = null
     /** UIDs the target calendar already holds, for import dedup. */
     var existingUidsResult: Set<String> = emptySet()
     /** Set to make the next write call throw. */
@@ -59,7 +61,10 @@ internal class FakeCalendarDataSource : CalendarDataSource {
     override fun eventDetail(eventId: Long): EventDetail? = eventDetailResult(eventId)
     override fun eventColorPalette(calendarId: Long): List<EventColorOption> =
         eventColorPaletteResult(calendarId)
-    override fun exportableEvents(calendarIds: Set<Long>?): List<IcsEvent> = exportableEventsResult
+    override fun exportableEvents(calendarIds: Set<Long>?): List<IcsEvent> {
+        lastExportableEventsCalendarIds = calendarIds
+        return exportableEventsResult
+    }
 
     override fun existingUids(calendarId: Long): Set<String> = existingUidsResult