Fix timestamp alignment for Android <12 bug in toTimestamp()

Author: sunkup

lib/src/main/kotlin/at/bitfire/synctools/util/AndroidTimeUtils.kt

@@ -75,6 +75,9 @@ object AndroidTimeUtils {
 
     /**
      * Same as [toInstant], but returns a UNIX timestamp (in milliseconds) instead of an [Instant].
+     * Aligned to full seconds, since Android <12 has a bug.
+     *
+     * See [at.bitfire.synctools.storage.calendar.AndroidCalendarProvider.matchesExceptionsWithMilliseconds].
      */
     fun Temporal.toTimestamp(): Long =
         toInstant().toEpochMilli()

lib/src/test/kotlin/at/bitfire/synctools/mapping/tasks/builder/CompletedBuilderTest.kt

@@ -12,6 +12,7 @@ import androidx.core.content.contentValuesOf
 import at.bitfire.DefaultTimezoneRule
 import at.bitfire.ical4android.Task
 import at.bitfire.synctools.test.assertContentValuesEqual
+import at.bitfire.synctools.util.AndroidTimeUtils.toTimestamp
 import net.fortuna.ical4j.model.property.Completed
 import org.dmfs.tasks.contract.TaskContract.Tasks
 import org.junit.Rule
@@ -20,6 +21,7 @@ import org.junit.runner.RunWith
 import org.robolectric.RobolectricTestRunner
 import java.time.Instant
 import java.time.LocalDateTime
+import java.time.ZoneId
 
 @RunWith(RobolectricTestRunner::class)
 class CompletedBuilderTest {
@@ -67,7 +69,7 @@ class CompletedBuilderTest {
         )
         // floating date-time is interpreted in system default timezone
         val expectedTimestamp = LocalDateTime.of(2024, 6, 1, 12, 0, 0)
-            .atZone(tzRule.defaultZoneId).toInstant().toEpochMilli()
+            .atZone(ZoneId.systemDefault()).toInstant().toTimestamp()
         assertContentValuesEqual(contentValuesOf(
             Tasks.COMPLETED to expectedTimestamp,
             Tasks.COMPLETED_IS_ALLDAY to 0