data: add CalendarPrefs (hidden calendar ids in DataStore)

app/src/test/java/de/jeanlucmakiola/calendula/data/prefs/CalendarPrefsTest.kt

@@ -0,0 +1,53 @@
+package de.jeanlucmakiola.calendula.data.prefs
+
+import androidx.datastore.core.DataStore
+import androidx.datastore.preferences.core.PreferenceDataStoreFactory
+import androidx.datastore.preferences.core.Preferences
+import com.google.common.truth.Truth.assertThat
+import kotlinx.coroutines.flow.first
+import kotlinx.coroutines.test.runTest
+import org.junit.jupiter.api.Test
+import org.junit.jupiter.api.io.TempDir
+import java.nio.file.Path
+
+class CalendarPrefsTest {
+
+    private fun newDataStore(tempDir: Path): DataStore<Preferences> =
+        PreferenceDataStoreFactory.create(
+            produceFile = { tempDir.resolve("test_prefs.preferences_pb").toFile() },
+        )
+
+    @Test
+    fun `hiddenCalendarIds defaults to empty when unset`(@TempDir tempDir: Path) = runTest {
+        val prefs = CalendarPrefs(newDataStore(tempDir))
+        assertThat(prefs.hiddenCalendarIds.first()).isEmpty()
+    }
+
+    @Test
+    fun `setHiddenCalendarIds round-trips through DataStore`(@TempDir tempDir: Path) = runTest {
+        val store = newDataStore(tempDir)
+        val prefs = CalendarPrefs(store)
+        prefs.setHiddenCalendarIds(setOf(1L, 42L, 7L))
+        assertThat(prefs.hiddenCalendarIds.first()).isEqualTo(setOf(1L, 42L, 7L))
+    }
+
+    @Test
+    fun `setting empty set clears storage`(@TempDir tempDir: Path) = runTest {
+        val prefs = CalendarPrefs(newDataStore(tempDir))
+        prefs.setHiddenCalendarIds(setOf(1L))
+        prefs.setHiddenCalendarIds(emptySet())
+        assertThat(prefs.hiddenCalendarIds.first()).isEmpty()
+    }
+
+    @Test
+    fun `garbage stored string is parsed defensively`(@TempDir tempDir: Path) = runTest {
+        val store = newDataStore(tempDir)
+        val prefs = CalendarPrefs(store)
+        store.updateData { p ->
+            val mutable = p.toMutablePreferences()
+            mutable[CalendarPrefs.HIDDEN_IDS_KEY] = "1,abc,3"
+            mutable
+        }
+        assertThat(prefs.hiddenCalendarIds.first()).isEqualTo(setOf(1L, 3L))
+    }
+}