Fix no/wrong default timezone registry factory set (#105)

* Add test to assert presence of AndroidCompatTimeZoneRegistry

* Add r8 proguard keep rule

* Use is to assert timezone registry

* Keep both the tz registry and its inner factory class as well

* Use explicit statements for keeping both the tz registry and its inner factory class

Author: sunkup

lib/consumer-rules.pro

@@ -10,6 +10,10 @@
 -dontwarn org.codehaus.groovy.**
 -dontwarn org.jparsec.**
 
+# keep to be used by ical4j
+-keep class at.bitfire.ical4android.AndroidCompatTimeZoneRegistry { *; }
+-keep class at.bitfire.ical4android.AndroidCompatTimeZoneRegistry$Factory { *; }
+
 # keep all vCard properties/parameters (used via reflection)
 -keep class ezvcard.io.scribe.** { *; }
 -keep class ezvcard.property.** { *; }

lib/src/test/kotlin/at/bitfire/ical4android/Ical4jConfigurationTest.kt

@@ -0,0 +1,25 @@
+/*
+ * This file is part of bitfireAT/synctools which is released under GPLv3.
+ * Copyright © All Contributors. See the LICENSE and AUTHOR files in the root directory for details.
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+package at.bitfire.ical4android
+
+import net.fortuna.ical4j.model.TimeZoneRegistryFactory
+import org.junit.Assert
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertNotNull
+import org.junit.Assert.assertTrue
+
+import org.junit.Test
+
+class Ical4jConfigurationTest {
+
+    @Test
+    fun testTimeZoneRegistryFactoryConfigured() {
+        val registry = TimeZoneRegistryFactory.getInstance().createRegistry()
+        assertTrue(registry is AndroidCompatTimeZoneRegistry)
+    }
+
+}