Initial commit: Busbar Designer

Web tool for designing nickel/copper busbars over cylindrical-cell battery
packs (21700, 18650) in hex holders. Flask + build123d backend exports
STEP/DXF/SVG; vanilla JS frontend with live preview, multi-project SQLite
persistence, snapshot history.

Deploy scripts in deploy/ (proxmox-lxc.sh, install.sh, update.sh).

tests/test_storage.py

@@ -0,0 +1,90 @@
+"""Sanity tests for storage.py — uses a fresh in-memory-ish DB per test."""
+
+import os
+import sys
+from pathlib import Path
+
+# Point the storage module at a tmp DB before importing it.
+TMP_DB = Path(__file__).parent / "_tmp_storage.db"
+os.environ["BUSBAR_DB"] = str(TMP_DB)
+
+sys.path.insert(0, str(Path(__file__).resolve().parents[1]))
+
+import storage  # noqa: E402
+
+
+def setup_function(_):
+    if TMP_DB.exists():
+        TMP_DB.unlink()
+    storage.init_db()
+
+
+def teardown_module(_):
+    if TMP_DB.exists():
+        TMP_DB.unlink()
+
+
+def test_project_crud():
+    pid = storage.create_project("test", {"cells": [{"x": 0, "y": 0}]})
+    assert pid > 0
+    p = storage.get_project(pid)
+    assert p["name"] == "test"
+    assert p["data"]["cells"][0]["x"] == 0
+
+    assert storage.update_project(pid, name="renamed")
+    assert storage.get_project(pid)["name"] == "renamed"
+
+    assert storage.update_project(pid, data={"cells": [], "params": {"k": 1}})
+    assert storage.get_project(pid)["data"]["params"]["k"] == 1
+
+    assert storage.delete_project(pid)
+    assert storage.get_project(pid) is None
+
+
+def test_snapshot_created_and_restore():
+    pid = storage.create_project("p", {"v": 1})
+    # snapshot=True means: snapshot the CURRENT (v=1) state before applying v=2
+    assert storage.update_project(pid, data={"v": 2}, snapshot=True, note="step")
+    snaps = storage.list_snapshots(pid)
+    assert len(snaps) == 1
+    assert snaps[0]["note"] == "step"
+
+    sid = snaps[0]["id"]
+    snap = storage.get_snapshot(sid)
+    assert snap["data"]["v"] == 1   # the *prior* state
+
+    # Restore: rolls project back to v=1 (and creates another snapshot of v=2).
+    assert storage.restore_snapshot(sid)
+    assert storage.get_project(pid)["data"]["v"] == 1
+    assert len(storage.list_snapshots(pid)) == 2
+
+
+def test_snapshot_retention_caps_at_N():
+    pid = storage.create_project("p", {"v": 0})
+    for i in range(1, storage.SNAPSHOT_RETENTION + 10):
+        storage.update_project(pid, data={"v": i}, snapshot=True)
+    snaps = storage.list_snapshots(pid)
+    assert len(snaps) == storage.SNAPSHOT_RETENTION
+
+
+def test_preset_crud_and_name_unique():
+    pid = storage.create_preset("21700", {"cellDia": 21.2})
+    assert pid > 0
+    assert storage.create_preset("21700", {"x": 1}) is None  # name collision
+
+    assert storage.list_presets()[0]["params"]["cellDia"] == 21.2
+
+    assert storage.update_preset(pid, params={"cellDia": 21.4})
+    assert storage.get_preset(pid)["params"]["cellDia"] == 21.4
+
+    assert storage.delete_preset(pid)
+    assert storage.list_presets() == []
+
+
+def test_delete_project_cascades_snapshots():
+    pid = storage.create_project("p", {"v": 1})
+    storage.update_project(pid, data={"v": 2}, snapshot=True)
+    storage.update_project(pid, data={"v": 3}, snapshot=True)
+    assert len(storage.list_snapshots(pid)) == 2
+    storage.delete_project(pid)
+    assert storage.list_snapshots(pid) == []