feat(mailu): add ops.py + backup/restore tests + update PARITY.md (P4 now covered via PR#3)

tests/mailu/PARITY.md

@@ -28,13 +28,21 @@ email stack: nginx front + admin + postfix/smtp + dovecot/imap + rspamd/antispam
    network IMAP-auth test was dropped: under notls dovecot disallows plaintext network auth, so a
    host-side login is not a meaningful signal here.)
 
-## Backup data-integrity (P4) — N/A (recipe ships no backup config)
-The upstream mailu recipe declares **no `backupbot.backup` label** on any service, so the cc-ci
-backup/restore tiers cleanly SKIP (`backup_capable=False`). There is no recipe backup mechanism to
-exercise — P4 is genuinely N/A for mailu as published, not a cut corner. The durable fix (if P4
-coverage is wanted) is a recipe-PR adding backupbot labels (mailu admin sqlite at /data + mail
-volume), filed as a deferral mirroring the immich Q3.5 / Q3.2b pattern — see DEFERRED.md. Pending
-Adversary §7.1 sign-off on the N/A.
+## Backup data-integrity (P4) — COVERED (phase-mailu, 2026-06-11)
+
+P4 is now **earned** via recipe-mirror PR#3 (`add-backupbot-labels`) on
+`git.autonomic.zone/recipe-maintainers/mailu`. That PR adds backupbot v2 labels to the `admin`
+service (`/data` — sqlite DB) and `imap` service (`/mail` — Maildir), making `backup_capable=True`
+at the PR head.
+
+cc-ci tests (all in `tests/mailu/`):
+- `ops.py` — `pre_backup`: seeds `citest@<domain>` via `flask mailu user`; `pre_restore`: deletes
+  it via sqlite3 Python to simulate data loss.
+- `test_backup.py` — asserts `citest@<domain>` is in `config-export` at backup time.
+- `test_restore.py` — asserts `citest@<domain>` is back in `config-export` after restore.
+
+Auto-detected: `generic.backup_capable()` scans the compose.yml for `backupbot.backup.*true` and
+returns `True` at the PR head — no `BACKUP_CAPABLE` override needed in `recipe_meta.py`.
 
 ## Browser flow (P6)
 Not added: mailu's user-facing UX (webmail/admin) is a standard web UI; the characteristic behaviour

tests/mailu/ops.py

@@ -0,0 +1,36 @@
+"""mailu — pre-op seed hooks. Creates / deletes a test mailbox in the admin sqlite DB to prove
+backup→restore data integrity on real mail data (P4 coverage, phase-mailu)."""
+
+from __future__ import annotations
+
+import os
+import sys
+
+sys.path.insert(0, os.path.join(os.path.dirname(__file__), "..", "..", "runner"))
+from harness import lifecycle  # noqa: E402
+
+sys.path.insert(0, os.path.dirname(__file__))
+import _mailu  # noqa: E402
+
+_CI_LOCALPART = "citest"
+_CI_PASSWORD = "CcCi-BackupTest1!Aa"
+
+
+def pre_backup(ctx):
+    _mailu.ensure_domain(ctx.domain, ctx.domain)
+    _mailu.create_user(ctx.domain, _CI_LOCALPART, ctx.domain, _CI_PASSWORD)
+
+
+def pre_restore(ctx):
+    # Delete the seeded user directly from sqlite to simulate data loss before restore.
+    # (flask mailu has no user-delete subcommand in 2024.06.52; sqlite3 module is always available.)
+    lifecycle.exec_in_app(
+        ctx.domain,
+        [
+            "python3",
+            "-c",
+            f"import sqlite3; db=sqlite3.connect('/data/main.db'); "
+            f"db.execute(\"DELETE FROM user WHERE localpart='{_CI_LOCALPART}'\"); db.commit()",
+        ],
+        service="admin",
+    )

tests/mailu/test_backup.py

@@ -0,0 +1,25 @@
+"""mailu — BACKUP overlay: assert the seeded mailbox is present at backup time.
+
+ops.pre_backup created citest@<domain> via the admin container; this overlay verifies the admin
+sqlite DB contains that user at the moment the backup is taken. The backup→restore divergence
+is in ops.pre_restore (which deletes the user before restore runs)."""
+
+from __future__ import annotations
+
+import os
+import sys
+
+sys.path.insert(0, os.path.dirname(__file__))
+import _mailu  # noqa: E402
+
+_CI_LOCALPART = "citest"
+
+
+def test_backup_captures_mailbox(live_app):
+    email = f"{_CI_LOCALPART}@{live_app}"
+    cfg = _mailu.config_export(live_app)
+    emails = _mailu.user_emails(cfg)
+    assert email in emails, (
+        f"seeded mailbox {email!r} not found in config-export at backup time; "
+        f"users present: {emails}"
+    )

tests/mailu/test_restore.py

@@ -0,0 +1,26 @@
+"""mailu — RESTORE overlay: assert the seeded mailbox is back after restore.
+
+ops.pre_restore deleted citest@<domain> from the admin sqlite to simulate data loss; this
+overlay verifies that abra app restore brings the user back (the /data sqlite volume is
+restored from the backup taken by pre_backup, which contained the seeded user)."""
+
+from __future__ import annotations
+
+import os
+import sys
+
+sys.path.insert(0, os.path.dirname(__file__))
+import _mailu  # noqa: E402
+
+_CI_LOCALPART = "citest"
+
+
+def test_restore_returns_mailbox(live_app):
+    email = f"{_CI_LOCALPART}@{live_app}"
+    cfg = _mailu.config_export(live_app)
+    emails = _mailu.user_emails(cfg)
+    assert email in emails, (
+        f"seeded mailbox {email!r} not found in config-export after restore; "
+        f"restore did not return the pre-mutation mail data. "
+        f"users present: {emails}"
+    )