fix(e2e): add test isolation for note-modal Slate editor tests (#132)

* fix(e2e): add resetProjectInfoNotes for test isolation in note-modal

The note-modal tests were flaky on CI because the "save and persist"
test writes content to the DB, and subsequent tests (slash command,
heading autoformat) inherit that state. Ctrl+A+Backspace to clear
Slate editors is inherently unreliable on slow CI runners.

Fix: add resetProjectInfoNotes() helper that resets note fields to
seed values before each test, ensuring a known starting state.

* fix(e2e): check Slate placeholder visibility for empty editor assertion

When the Plate/Slate editor is empty, it renders a placeholder element
with data-slate-placeholder="true". textContent() captures this
placeholder text, causing the emptiness check to fail. Use placeholder
element visibility instead — a visible placeholder means the editor
is truly empty.

Author: ryota-murakami

e2e/helpers/db-query.ts

@@ -300,6 +300,46 @@ export async function resetProjectInfoComments(): Promise<void> {
   }
 }
 
+/**
+ * Reset projectinfo notes to seed.sql initial values.
+ * Call this in beforeEach for tests that interact with the Plate editor
+ * to ensure a known starting state (avoids flaky Ctrl+A clear on CI).
+ *
+ * @example
+ * test.beforeEach(async () => {
+ *   await resetProjectInfoNotes()
+ * })
+ */
+export async function resetProjectInfoNotes(): Promise<void> {
+  const supabase = createLocalSupabaseClient()
+
+  const seedNotes = [
+    { id: PROJECT_INFO_IDS.projinfo1, note: 'Important project notes here' },
+    { id: PROJECT_INFO_IDS.projinfo2, note: 'Another repo notes' },
+    { id: PROJECT_INFO_IDS.projinfo3, note: '' },
+    { id: PROJECT_INFO_IDS.projinfo4, note: 'CLI tool documentation' },
+  ]
+
+  for (const item of seedNotes) {
+    const { data, error } = await supabase
+      .from('projectinfo')
+      .update({ note: item.note })
+      .eq('id', item.id)
+      .select('id, note')
+    if (error) {
+      throw new Error(
+        `resetProjectInfoNotes: failed for id=${item.id}: ${error.message}`,
+      )
+    }
+    if (!data || data.length === 0) {
+      throw new Error(
+        `resetProjectInfoNotes: UPDATE matched 0 rows for id=${item.id}. ` +
+          `URL=${process.env.NEXT_PUBLIC_SUPABASE_URL || 'http://127.0.0.1:54321'}`,
+      )
+    }
+  }
+}
+
 /**
  * Reset all repo card positions to seed.sql initial values.
  * Call this in beforeEach for DnD card tests to ensure clean state.

e2e/logged-in/note-modal.spec.ts

@@ -18,6 +18,7 @@ import {
   PROJECT_INFO_IDS,
   BOARD_IDS,
   CARD_IDS,
+  resetProjectInfoNotes,
 } from '../helpers/db-query'
 
 /** Platform-aware modifier key: Cmd on macOS, Ctrl on Linux/Windows (CI) */
@@ -29,6 +30,9 @@ test.describe('NoteModal (Authenticated)', () => {
   const BOARD_URL = `/board/${BOARD_IDS.testBoard}`
 
   test.beforeEach(async ({ page }) => {
+    // Reset note content to seed values so each test starts with known state.
+    // This avoids flaky Ctrl+A+Backspace clears on slow CI runners.
+    await resetProjectInfoNotes()
     await page.goto(BOARD_URL)
     // Use networkidle to wait for all data fetches to complete
     // This prevents flakiness caused by cards not being rendered yet
@@ -237,22 +241,16 @@ test.describe('NoteModal (Authenticated)', () => {
     const editorContent = dialog.locator('[data-slate-editor="true"]')
     await editorContent.click()
 
-    // Clear existing content first
-    await page.keyboard.press(`${MOD}+a`)
-    await page.keyboard.press('Backspace')
-
-    // Ensure editor is ready and empty before typing slash command
-    // Type a character, wait for it to render, then clear and wait for editor to settle
-    await page.keyboard.type('x')
-    await expect(editorContent).toContainText('x')
-    await page.keyboard.press(`${MOD}+a`)
-    await page.keyboard.press('Backspace')
-    // Poll until Slate editor finishes processing the clear operation
+    // Clear existing content — retry inside polling loop for CI resilience
     await expect(async () => {
-      const text = await editorContent.textContent()
-      // Editor should be empty or contain only placeholder text
-      expect(text?.replace(/\s/g, '')).toBe('')
-    }).toPass({ timeout: 5000 })
+      await page.keyboard.press(`${MOD}+a`)
+      await page.keyboard.press('Backspace')
+      // When editor is empty, Plate shows a placeholder with data-slate-placeholder
+      const placeholder = editorContent.locator(
+        '[data-slate-placeholder="true"]',
+      )
+      await expect(placeholder).toBeVisible()
+    }).toPass({ timeout: 10000 })
 
     // Generous delay to let Slate editor fully stabilize after clear
     // CI runners (GitHub Actions Linux) need more time for contenteditable
@@ -379,6 +377,7 @@ test.describe('NoteModal Editor Height & Scroll (Authenticated)', () => {
   const BOARD_URL = `/board/${BOARD_IDS.testBoard}`
 
   test.beforeEach(async ({ page }) => {
+    await resetProjectInfoNotes()
     await page.goto(BOARD_URL)
     // Use networkidle to wait for all data fetches to complete
     // This prevents flakiness caused by cards not being rendered yet
@@ -514,6 +513,10 @@ test.describe('NoteModal Formatting (Authenticated)', () => {
 
   const BOARD_URL = `/board/${BOARD_IDS.testBoard}`
 
+  test.beforeEach(async () => {
+    await resetProjectInfoNotes()
+  })
+
   test('should support markdown autoformat for heading', async ({ page }) => {
     // Slate autoformat triggers are timing-sensitive on slow CI runners
     test.slow()
@@ -539,8 +542,12 @@ test.describe('NoteModal Formatting (Authenticated)', () => {
     await expect(async () => {
       await page.keyboard.press(`${MOD}+a`)
       await page.keyboard.press('Backspace')
-      const text = await editorContent.textContent()
-      expect(text?.replace(/\s/g, '')).toBe('')
+      // When editor is empty, Plate shows a placeholder (e.g. "Type / for commands...")
+      // which textContent() picks up. Check for placeholder element instead.
+      const placeholder = editorContent.locator(
+        '[data-slate-placeholder="true"]',
+      )
+      await expect(placeholder).toBeVisible()
     }).toPass({ timeout: 10000 })
 
     // Type markdown heading - the space after # triggers autoformat