feat(android): back the phone's contacts up to a group of one's own

A Contacts backup section on the Android Sync page sends a dated .vcf into
<folder>/<account>-contacts once a day when the address book changed, only
to a group the account is alone in, checked again at every run.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

1 files changed, 55 insertions, 0 deletions

diff --git a/packages/meshbay-android/app/src/test/kotlin/org/meshbay/client/DocSyncTest.kt b/packages/meshbay-android/app/src/test/kotlin/org/meshbay/client/DocSyncTest.kt
new file mode 100644
index 0000000..276f1fd
--- /dev/null
+++ b/packages/meshbay-android/app/src/test/kotlin/org/meshbay/client/DocSyncTest.kt
@@ -0,0 +1,55 @@
+package org.meshbay.client
+
+import org.json.JSONObject
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertNotEquals
+import org.junit.Assert.assertNull
+import org.junit.Assert.assertThrows
+import org.junit.Test
+import org.meshbay.client.phonesync.DocConfig
+import org.meshbay.client.phonesync.DocPlan
+import java.util.TimeZone
+
+class DocSyncTest {
+    private val utc = TimeZone.getTimeZone("UTC")
+    // 2026-10-09 12:00:00 UTC
+    private val oct9 = 1791547200000L
+
+    private fun settings(account: String = "bob", folder: String = "Backups") = JSONObject()
+        .put("account", account).put("groupId", "g1").put("groupName", "Mine").put("owner", "bob")
+        .put("folder", folder)
+
+    @Test fun `each kind goes into a folder of its own named for the account`() {
+        val c = DocConfig.fromJson(settings(folder = "/Backups/Phone/"))
+        assertEquals("Backups/Phone/bob-contacts", DocPlan.dirFor(c, "contacts"))
+        assertEquals("Backups/Phone/bob-messages", DocPlan.dirFor(c, "messages"))
+    }
+
+    @Test fun `a file is named for when it was taken, in the phone's time`() {
+        assertEquals("contacts-2026-10-09-1200.vcf", DocPlan.nameFor("contacts", "vcf", oct9, utc))
+        assertEquals("contacts-2026-10-09-1400.vcf",
+                     DocPlan.nameFor("contacts", "vcf", oct9, TimeZone.getTimeZone("Europe/Paris")))
+    }
+
+    @Test fun `a folder that climbs out or an account that is not a name is refused`() {
+        for (bad in listOf("../etc", "Backups/../x", "Backups//x", "./x", "")) {
+            assertThrows(bad, IllegalArgumentException::class.java) { DocConfig.fromJson(settings(folder = bad)) }
+        }
+        for (bad in listOf("../bob", "bob/x", "", "-bob")) {
+            assertThrows(bad, IllegalArgumentException::class.java) { DocConfig.fromJson(settings(account = bad)) }
+        }
+    }
+
+    @Test fun `settings survive being stored`() {
+        val c = DocConfig.fromJson(settings())
+        assertEquals(c, DocConfig.parse(c.toJson().toString()))
+        assertNull(DocConfig.parse("{not json"))
+    }
+
+    @Test fun `another group or folder is another backup`() {
+        val a = DocConfig.fromJson(settings())
+        assertNotEquals(a.ledgerKey, DocConfig.fromJson(settings(folder = "Other")).ledgerKey)
+        assertNotEquals(a.ledgerKey, DocConfig.fromJson(settings().put("groupId", "g2")).ledgerKey)
+        assertEquals(a.ledgerKey, DocConfig.fromJson(settings().put("groupName", "Renamed")).ledgerKey)
+    }
+}