Remove orphaned attachments when creating a new backup.

app/src/test/java/org/thoughtcrime/securesms/backup/v2/ArchivedMediaObjectIteratorTest.kt

@@ -0,0 +1,43 @@
+package org.thoughtcrime.securesms.backup.v2
+
+import org.junit.Before
+import org.junit.Test
+import org.mockito.kotlin.any
+import org.mockito.kotlin.mock
+import org.mockito.kotlin.whenever
+import org.thoughtcrime.securesms.MockCursor
+import org.thoughtcrime.securesms.assertIsSize
+
+class ArchivedMediaObjectIteratorTest {
+
+  private val cursor: MockCursor = mock()
+
+  @Before
+  fun setUp() {
+    whenever(cursor.getString(any())).thenReturn("A")
+    whenever(cursor.moveToPosition(any())).thenCallRealMethod()
+    whenever(cursor.moveToNext()).thenCallRealMethod()
+    whenever(cursor.position).thenCallRealMethod()
+    whenever(cursor.isLast).thenCallRealMethod()
+    whenever(cursor.isAfterLast).thenCallRealMethod()
+  }
+
+  @Test
+  fun `Given a cursor with 0 items, when I convert to a list, then I expect a size of 0`() {
+    runTest(0)
+  }
+
+  @Test
+  fun `Given a cursor with 100 items, when I convert to a list, then I expect a size of 100`() {
+    runTest(100)
+  }
+
+  private fun runTest(size: Int) {
+    whenever(cursor.count).thenReturn(size)
+    val iterator = ArchivedMediaObjectIterator(cursor)
+
+    val list = iterator.asSequence().toList()
+
+    list.assertIsSize(size)
+  }
+}