Major update for v1 and tests

src/test/setup.js

@@ -0,0 +1,45 @@
+// Vitest setup file — runs once per test file, before any test.
+//
+// Two responsibilities:
+//
+//   1. Register @testing-library/jest-dom's custom matchers so tests
+//      can use `expect(node).toBeInTheDocument()`, `toHaveTextContent()`,
+//      `toHaveAttribute()`, etc. Without this import, those matchers
+//      throw "expected jest-dom matcher" at assertion time.
+//
+//   2. Run RTL's `cleanup()` after every test. RTL renders into a
+//      shared DOM container; without explicit cleanup, components
+//      from one test stick around for the next, producing
+//      false-positive "found multiple instances" errors and
+//      memory-grow bugs in long suites. Vitest with `globals: true`
+//      exposes `afterEach` so the import below works without
+//      naming it on the import side.
+//
+// What's NOT here (intentionally)
+// ─────────────────────────────────
+//   • localStorage clearing. jsdom gives each test file a fresh
+//     localStorage, and our tests that touch localStorage (history
+//     debug flag) explicitly set+clear their own keys per test.
+//     A blanket `localStorage.clear()` in afterEach would mask
+//     setup bugs in tests that depend on a clean key.
+//
+//   • Konva mocking. We don't yet have tests that mount React-Konva
+//     components — those will need Stage/Layer stubs and will live
+//     in a follow-up batch once we know the test setup story for
+//     canvas-dependent code. For pure utility and hook tests
+//     covered in this initial batch, Konva isn't loaded.
+//
+//   • Timer mocking globals. Individual tests that need
+//     `vi.useFakeTimers()` (debounce tests for updateElement, the
+//     auto-dismiss toast timer, etc.) call it themselves and pair
+//     with `vi.useRealTimers()` in their own afterEach. Keeping
+//     it test-local rather than global makes the timing intent
+//     visible at the test site.
+
+import '@testing-library/jest-dom/vitest';
+import { afterEach } from 'vitest';
+import { cleanup } from '@testing-library/react';
+
+afterEach(() => {
+  cleanup();
+});