From 00a82505c46d3beb8d7af0df293e88cc363dd394 Mon Sep 17 00:00:00 2001
From: Neil <4138956+nwparker@users.noreply.github.com>
Date: Wed, 7 Oct 2026 21:01:48 -0700
Subject: [PATCH] test: speed terminal comparisons and retry policy checks
 (#26396)

---
 .../daemon/serialize-grid-cell-descriptors.ts | 25 ++++++++++++++++++-
 .../electron-main-evaluate-retry.unit.test.ts | 16 +++++++++---
 2 files changed, 37 insertions(+), 4 deletions(-)

diff --git a/src/main/daemon/serialize-grid-cell-descriptors.ts b/src/main/daemon/serialize-grid-cell-descriptors.ts
index 9adbbc6c694..9efc74221f7 100644
--- a/src/main/daemon/serialize-grid-cell-descriptors.ts
+++ b/src/main/daemon/serialize-grid-cell-descriptors.ts
@@ -132,6 +132,29 @@ function sameCellFields(expected: Cell, actual: Cell): boolean {
   )
 }
 
+// Match the frozen default-blank descriptor without formatting every trailing cell.
+function isDefaultBlank(line: BufferLine | undefined, x: number, scratch: Cell): boolean {
+  if (!line || x >= line.length) {
+    return true
+  }
+  const cell = line.getCell(x, scratch)
+  if (!cell) {
+    return true
+  }
+  const chars = cell.getChars()
+  return (
+    cell.getWidth() === 1 &&
+    cell.getBgColorMode() === 0 &&
+    cell.getBgColor() === -1 &&
+    cell.isInverse() === 0 &&
+    (chars === '' ||
+      (chars === ' ' &&
+        cell.isUnderline() === 0 &&
+        cell.isStrikethrough() === 0 &&
+        cell.isOverline() === 0))
+  )
+}
+
 function trimmedEnd(
   buffer: Buffer,
   start: number,
@@ -143,7 +166,7 @@ function trimmedEnd(
     const line = buffer.getLine(end - 1)
     let blank = true
     for (let x = 0; x < cols; x++) {
-      if (cellDescriptor(line, x, cols, scratch) !== DEFAULT_BLANK) {
+      if (!isDefaultBlank(line, x, scratch)) {
         blank = false
         break
       }
diff --git a/tests/e2e/helpers/electron-main-evaluate-retry.unit.test.ts b/tests/e2e/helpers/electron-main-evaluate-retry.unit.test.ts
index c6735e2fd1f..95b5754e596 100644
--- a/tests/e2e/helpers/electron-main-evaluate-retry.unit.test.ts
+++ b/tests/e2e/helpers/electron-main-evaluate-retry.unit.test.ts
@@ -1,4 +1,4 @@
-import { describe, expect, it } from 'vitest'
+import { afterEach, describe, expect, it, vi } from 'vitest'
 import { retryTransientMainEvaluate } from './electron-main-evaluate-retry'
 
 const transientMessages = [
@@ -6,6 +6,8 @@ const transientMessages = [
   'electronApplication.evaluate: Resulting promise was garbage collected.'
 ]
 
+afterEach(() => vi.useRealTimers())
+
 describe('retryTransientMainEvaluate', () => {
   it('returns the first successful read without retrying', async () => {
     let calls = 0
@@ -19,8 +21,9 @@ describe('retryTransientMainEvaluate', () => {
   })
 
   it.each(transientMessages)('retries a transient startup failure: %s', async (message) => {
+    vi.useFakeTimers({ toFake: ['setTimeout', 'clearTimeout'] })
     let calls = 0
-    await expect(
+    const outcome = expect(
       retryTransientMainEvaluate(async () => {
         calls += 1
         if (calls < 3) {
@@ -29,6 +32,9 @@ describe('retryTransientMainEvaluate', () => {
         return '/isolated/home'
       })
     ).resolves.toBe('/isolated/home')
+    void outcome.catch(() => undefined)
+    await vi.advanceTimersByTimeAsync(400)
+    await outcome
     expect(calls).toBe(3)
   })
 
@@ -46,13 +52,17 @@ describe('retryTransientMainEvaluate', () => {
   it.each(transientMessages)(
     'bounds retries when evaluation keeps failing: %s',
     async (message) => {
+      vi.useFakeTimers({ toFake: ['setTimeout', 'clearTimeout'] })
       let calls = 0
-      await expect(
+      const outcome = expect(
         retryTransientMainEvaluate(async () => {
           calls += 1
           throw new Error(message)
         })
       ).rejects.toThrow(message)
+      void outcome.catch(() => undefined)
+      await vi.advanceTimersByTimeAsync(800)
+      await outcome
       expect(calls).toBe(5)
     }
   )