test(core): backup round-trips reference image bytes

crates/relicario-core/tests/backup.rs

@@ -91,3 +91,16 @@ fn populated_vault_round_trip() {
     assert_eq!(by_aid.get(&("1111111111111111", "aaaa1111")).unwrap(), &&attach_x_ct);
     assert_eq!(by_aid.get(&("2222222222222222", "bbbb2222")).unwrap(), &&attach_y_ct);
 }
+
+#[test]
+fn round_trip_with_reference_image() {
+    let jpg_bytes: Vec<u8> = (0u8..=255).cycle().take(1024 * 64).collect(); // 64 KiB
+    let mut input = empty_input();
+    input.reference_jpg = Some(&jpg_bytes);
+
+    let out = pack_backup(input, "p").unwrap();
+    let unpacked = unpack_backup(&out, "p").unwrap();
+
+    assert_eq!(unpacked.reference_jpg.as_deref(), Some(jpg_bytes.as_slice()));
+    assert!(unpacked.git_archive.is_none());
+}