diff --git a/crates/relicario-core/tests/backup.rs b/crates/relicario-core/tests/backup.rs
index 9dabdcb..d424e89 100644
--- a/crates/relicario-core/tests/backup.rs
+++ b/crates/relicario-core/tests/backup.rs
@@ -30,3 +30,64 @@ fn empty_vault_round_trip() {
     assert!(unpacked.reference_jpg.is_none());
     assert!(unpacked.git_archive.is_none());
 }
+
+use relicario_core::backup::{BackupAttachment, BackupItem};
+
+#[test]
+fn populated_vault_round_trip() {
+    let manifest_enc = vec![0xDE, 0xAD, 0xBE, 0xEF, 0x42];
+    let settings_enc = vec![0x01, 0x02, 0x03];
+    let item_a_ct = vec![0xAA; 100];
+    let item_b_ct = vec![0xBB; 200];
+    let attach_x_ct = vec![0xCC; 4096];
+    let attach_y_ct = vec![0xDD; 8192];
+
+    let input = BackupInput {
+        salt: &[0x77u8; 32],
+        params_json: r#"{"format_version":2,"kdf":{"argon2_m":256,"argon2_t":1,"argon2_p":1},"aead":"xchacha20poly1305","salt_path":".relicario/salt"}"#,
+        devices_json: r#"[{"name":"laptop","public_key":"deadbeef"}]"#,
+        manifest_enc: &manifest_enc,
+        settings_enc: &settings_enc,
+        items: vec![
+            BackupItem { id: "1111111111111111".to_string(), ciphertext: &item_a_ct },
+            BackupItem { id: "2222222222222222".to_string(), ciphertext: &item_b_ct },
+        ],
+        attachments: vec![
+            BackupAttachment {
+                item_id: "1111111111111111".to_string(),
+                attachment_id: "aaaa1111".to_string(),
+                ciphertext: &attach_x_ct,
+            },
+            BackupAttachment {
+                item_id: "2222222222222222".to_string(),
+                attachment_id: "bbbb2222".to_string(),
+                ciphertext: &attach_y_ct,
+            },
+        ],
+        reference_jpg: None,
+        git_archive: None,
+    };
+
+    let out = pack_backup(input, "another-strong-passphrase").unwrap();
+    let unpacked = unpack_backup(&out, "another-strong-passphrase").unwrap();
+
+    assert_eq!(unpacked.salt, [0x77u8; 32]);
+    assert!(unpacked.devices_json.contains("laptop"));
+    assert_eq!(unpacked.manifest_enc, manifest_enc);
+    assert_eq!(unpacked.settings_enc, settings_enc);
+
+    assert_eq!(unpacked.items.len(), 2);
+    let by_id: std::collections::HashMap<_, _> =
+        unpacked.items.iter().map(|i| (i.id.as_str(), &i.ciphertext)).collect();
+    assert_eq!(by_id.get("1111111111111111").unwrap(), &&item_a_ct);
+    assert_eq!(by_id.get("2222222222222222").unwrap(), &&item_b_ct);
+
+    assert_eq!(unpacked.attachments.len(), 2);
+    let by_aid: std::collections::HashMap<_, _> = unpacked
+        .attachments
+        .iter()
+        .map(|a| ((a.item_id.as_str(), a.attachment_id.as_str()), &a.ciphertext))
+        .collect();
+    assert_eq!(by_aid.get(&("1111111111111111", "aaaa1111")).unwrap(), &&attach_x_ct);
+    assert_eq!(by_aid.get(&("2222222222222222", "bbbb2222")).unwrap(), &&attach_y_ct);
+}