feat(db): gated WAL-safe restore of seismo_relay.db + waveforms

tests/test_db_snapshot.py

@@ -79,3 +79,55 @@ def test_recent_waveforms_zip_bundles_all_per_event_files(tmp_path):
         "BE111/BBBB2222.OE0H.a5.pkl",
         "BE111/BBBB2222.OE0H.sfm.json",
     }
+
+
+def test_sfm_db_restore_enabled_reads_env(monkeypatch):
+    from sfm.db_snapshot import sfm_db_restore_enabled
+    monkeypatch.delenv("SFM_DB_RESTORE_ENABLED", raising=False)
+    assert sfm_db_restore_enabled() is False
+    monkeypatch.setenv("SFM_DB_RESTORE_ENABLED", "true")
+    assert sfm_db_restore_enabled() is True
+    monkeypatch.setenv("SFM_DB_RESTORE_ENABLED", "0")
+    assert sfm_db_restore_enabled() is False
+
+
+def test_restore_swaps_db_and_unpacks_waveforms(tmp_path):
+    import zipfile
+    from sfm.db_snapshot import restore_db_and_waveforms
+
+    db_path = tmp_path / "seismo_relay.db"
+    _make_db(db_path, rows=1)
+    (tmp_path / "seismo_relay.db-wal").write_bytes(b"stale")   # must be cleared
+
+    new_db = tmp_path / "incoming.db"
+    _make_db(new_db, rows=9)
+
+    wf_root = tmp_path / "waveforms"
+    wf_root.mkdir()
+    wf_zip = tmp_path / "wf.zip"
+    with zipfile.ZipFile(wf_zip, "w") as zf:
+        zf.writestr("BE111/AAAA.OE0H", b"x")
+        zf.writestr("BE111/AAAA.OE0H.h5", b"x")
+
+    result = restore_db_and_waveforms(db_path, wf_root, new_db, wf_zip)
+
+    conn = sqlite3.connect(str(db_path))
+    assert conn.execute("SELECT COUNT(*) FROM t").fetchone()[0] == 9
+    conn.close()
+    assert not (tmp_path / "seismo_relay.db-wal").exists()
+    assert (wf_root / "BE111" / "AAAA.OE0H.h5").exists()
+    assert result["ok"] and result["waveforms_unpacked"] == 2
+    assert result["safety_backup"] is not None
+
+
+def test_restore_rejects_non_sqlite(tmp_path):
+    import pytest
+    from sfm.db_snapshot import restore_db_and_waveforms
+    db_path = tmp_path / "seismo_relay.db"
+    _make_db(db_path, rows=1)
+    bogus = tmp_path / "bogus.db"
+    bogus.write_bytes(b"not a sqlite file at all")
+    wf_root = tmp_path / "waveforms"
+    wf_root.mkdir()
+    with pytest.raises(ValueError):
+        restore_db_and_waveforms(db_path, wf_root, bogus, None)