test: Playwright smoke test for note filename rename on save

Covers: title change + save renames file, no rename when filename matches,
rapid title edits rename to final title.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

tests/smoke/fix-note-filename-on-rename.spec.ts

@@ -0,0 +1,100 @@
+import { test, expect } from '@playwright/test'
+import { sendShortcut } from './helpers'
+
+/** Known BlockNote/ProseMirror error that fires during editor re-mount after rename. */
+const KNOWN_EDITOR_ERRORS = ['isConnected']
+
+function isKnownEditorError(msg: string): boolean {
+  return KNOWN_EDITOR_ERRORS.some(k => msg.includes(k))
+}
+
+/**
+ * Helper: create a new note, select the existing H1 heading text,
+ * replace it with a new title, then wait for the 500 ms title-sync debounce.
+ */
+async function createNoteWithTitle(page: import('@playwright/test').Page, title: string) {
+  // 1. Cmd+N → new "Untitled note" (creates heading with "Untitled note")
+  await page.locator('body').click()
+  await sendShortcut(page, 'n', ['Control'])
+  await expect(page.getByText(/Untitled note/).first()).toBeVisible({ timeout: 3000 })
+
+  // 2. Wait for the heading to render in BlockNote
+  const heading = page.locator('[data-content-type="heading"] h1')
+  await heading.waitFor({ timeout: 3000 })
+
+  // 3. Triple-click the heading to select all its text, then type replacement
+  await heading.click({ clickCount: 3 })
+  await page.keyboard.type(title, { delay: 20 })
+
+  // 4. Wait for the 500 ms useHeadingTitleSync debounce to fire + React re-render
+  await page.waitForTimeout(800)
+}
+
+test.describe('Note filename updates on title change + save', () => {
+  test.beforeEach(async ({ page }) => {
+    await page.goto('/')
+    await page.waitForLoadState('networkidle')
+    // Wait for startup toast ("Laputa registered as MCP tool") to dismiss
+    await page.waitForTimeout(2500)
+  })
+
+  test('Cmd+N creates untitled note, typing new title + Cmd+S renames file', async ({ page }) => {
+    const errors: string[] = []
+    page.on('pageerror', (err) => { if (!isKnownEditorError(err.message)) errors.push(err.message) })
+
+    await createNoteWithTitle(page, 'Test Note ABC')
+
+    // Breadcrumb should already show the new title (title sync fired)
+    const breadcrumb = page.locator('span.truncate.font-medium')
+    await expect(breadcrumb.first()).toContainText('Test Note ABC', { timeout: 2000 })
+
+    // 5. Cmd+S → save + rename
+    await sendShortcut(page, 's', ['Control'])
+
+    // 6. Toast should show "Renamed" (appears within 5s, auto-dismisses after 2s)
+    const toast = page.locator('.fixed.bottom-8')
+    await expect(toast).toContainText('Renamed', { timeout: 5000 })
+
+    // 7. No unexpected JS errors
+    expect(errors).toEqual([])
+  })
+
+  test('saving a note whose filename already matches does not trigger rename', async ({ page }) => {
+    // Click on an existing note in the note list that already has a matching filename.
+    // The default sidebar shows "Notes" section with several notes visible.
+    const noteItem = page.locator('.truncate.text-foreground.font-medium').filter({ hasText: /Refactoring/ }).first()
+    await noteItem.click()
+    await page.waitForTimeout(500)
+
+    // Cmd+S — should show "Saved" or "Nothing to save", NOT "Renamed"
+    await sendShortcut(page, 's', ['Control'])
+
+    const toast = page.locator('.fixed.bottom-8')
+    await expect(toast).toBeVisible({ timeout: 3000 })
+    const toastText = await toast.textContent()
+    expect(toastText).not.toContain('Renamed')
+  })
+
+  test('rapid title changes only rename to final title on Cmd+S', async ({ page }) => {
+    const errors: string[] = []
+    page.on('pageerror', (err) => { if (!isKnownEditorError(err.message)) errors.push(err.message) })
+
+    await createNoteWithTitle(page, 'First Title')
+
+    // Select heading text again and replace with final title
+    const heading = page.locator('[data-content-type="heading"] h1')
+    await heading.click({ clickCount: 3 })
+    await page.keyboard.type('Final Title', { delay: 20 })
+
+    // Wait for debounce again
+    await page.waitForTimeout(800)
+
+    // Cmd+S → should rename to final-title.md
+    await sendShortcut(page, 's', ['Control'])
+
+    const toast = page.locator('.fixed.bottom-8')
+    await expect(toast).toContainText('Renamed', { timeout: 5000 })
+
+    expect(errors).toEqual([])
+  })
+})