test: restore minimized Transit windows before screenshots

changelog.d/1282-polling-issue-fix.md

@@ -4,3 +4,4 @@
 - Bound the Transit card-anchor probe by observed poll coverage instead of a fixed 20-second window (asturksever, #1282).
 - Keep visible-page Transit probes focused through the browser testing API (asturksever, #1282).
 - Add a real-browser regression gate for hidden-tab periodic work, explicit refresh, resume and teardown (asturksever, #1282).
+- Restore minimized test windows before screenshots so native compositor pauses cannot stall browser acceptance (asturksever, #1282).

scripts/qa-chrome.mjs

@@ -18,3 +18,30 @@ export function chromeExecutablePath({
   if (env.PUPPETEER_EXECUTABLE_PATH) return env.PUPPETEER_EXECUTABLE_PATH;
   return exists(MACOS_CHROME) ? MACOS_CHROME : undefined;
 }
+
+/** Restore an owned test window before capture: focus emulation alone does not
+ * unminimize the native compositor, so CDP screenshots can otherwise stall. */
+export async function captureQaScreenshot(
+  page,
+  options,
+  { headful = true } = {},
+) {
+  if (headful) {
+    const session = await page.createCDPSession();
+    try {
+      const { windowId, bounds } = await session.send(
+        'Browser.getWindowForTarget',
+      );
+      if (bounds.windowState === 'minimized') {
+        await session.send('Browser.setWindowBounds', {
+          windowId,
+          bounds: { windowState: 'normal' },
+        });
+      }
+      await page.bringToFront();
+    } finally {
+      await session.detach();
+    }
+  }
+  return page.screenshot(options);
+}

scripts/qa-transit-recovery.mjs

@@ -1,6 +1,6 @@
 /** Camera-jump regression against an existing server; never starts a server. */
 import puppeteer from 'puppeteer';
-import { chromeExecutablePath } from './qa-chrome.mjs';
+import { chromeExecutablePath, captureQaScreenshot } from './qa-chrome.mjs';
 import { mkdir, writeFile } from 'node:fs/promises';
 import { reduceTrailPixels } from '../src/layers/transit/qaMetrics.js';
 
@@ -307,7 +307,7 @@ try {
   result.pixelPass = pixels.pass;
   result.pixelDetails = pixels;
   result.errors = errors;
-  await page.screenshot({ path: `${shots}/recovery.png` });
+  await captureQaScreenshot(page, { path: `${shots}/recovery.png` });
   await writeFile(`${shots}/recovery.json`, JSON.stringify(result, null, 2));
   for (const key of ['on', 'off', 'onAgain', 'offAgain']) delete result[key];
   const pass =

scripts/qa-transit-scenes.mjs

@@ -1,3 +1,4 @@
+import { captureQaScreenshot } from './qa-chrome.mjs';
 import { getRegisteredTransitFeed } from '../src/data/transitFeeds.js';
 
 // Not registered or active: camera discovery and live polls never own this feed.
@@ -219,7 +220,7 @@ export async function runFleetBudgets({
         allocations.layerFrameBytes / allocationTrace.rows.length <= 8192,
       `${allocations.layerFrameBytes / allocationTrace.rows.length} transit-authored bytes/frame; whole frame ${allocations.frameBytes / allocationTrace.rows.length}; top three ${JSON.stringify(details.topAllocatorsPerFrame)}; collected objects included. Full profile saved.`,
     );
-    await page.screenshot({
+    await captureQaScreenshot(page, {
       path: `${shots}/${tag}-fleet-${count}.jpg`,
       type: 'jpeg',
       quality: 85,
@@ -392,7 +393,7 @@ export async function runBostonMatrix({
         JSON.stringify({ pixels, contrast }),
         { unexercised: pixels.length < 6 },
       );
-      await page.screenshot({
+      await captureQaScreenshot(page, {
         path: `${shots}/${tag}-matrix-${background.name}-${look.name}-fleet.jpg`,
         type: 'jpeg',
         quality: 90,
@@ -407,7 +408,7 @@ export async function runBostonMatrix({
           target.key,
         );
         await wait(500);
-        await page.screenshot({
+        await captureQaScreenshot(page, {
           path: `${shots}/${tag}-matrix-${background.name}-${look.name}-${target.route}-selected.jpg`,
           type: 'jpeg',
           quality: 90,
@@ -431,7 +432,7 @@ export async function runBostonMatrix({
         );
       }
       await wait(300);
-      await page.screenshot({
+      await captureQaScreenshot(page, {
         path: `${shots}/${tag}-matrix-${background.name}-${look.name}-restored.jpg`,
         type: 'jpeg',
         quality: 90,
@@ -579,7 +580,7 @@ export async function runBostonLive({
       JSON.stringify(selection),
       { unexercised: !target },
     );
-    await page.screenshot({
+    await captureQaScreenshot(page, {
       path: `${shots}/${tag}-boston-live-${view.name}.jpg`,
       type: 'jpeg',
       quality: 90,
@@ -1010,7 +1011,7 @@ export async function runTrailVisibility({
     stable: pixels.stable[i],
     eligible: pixels.eligible[i],
   }));
-  await page.screenshot({
+  await captureQaScreenshot(page, {
     path: `${shots}/${tag}-${altitude}m-trail-visible.jpg`,
     type: 'jpeg',
     quality: 95,

scripts/qa-transit.mjs

@@ -36,7 +36,7 @@ import {
  */
 import { mkdir, readFile, writeFile } from 'node:fs/promises';
 import puppeteer from 'puppeteer';
-import { chromeExecutablePath } from './qa-chrome.mjs';
+import { chromeExecutablePath, captureQaScreenshot } from './qa-chrome.mjs';
 import { createTransitHistory } from '../server/providers/transitHistory.js';
 import { DETECTION_THEME_MAP } from '../src/overlays/worldOverlayTokens.js';
 import { transitModeTier } from '../src/data/transitPresetStyle.js';
@@ -294,11 +294,13 @@ page.on('request', (request) => {
 });
 
 const shot = (name, caption) =>
-  page
-    .screenshot({ path: `${SHOTS}/${name}`, type: 'jpeg', quality: 82 })
-    .then(() => {
-      console.log(`  shot ${name} — ${caption}`);
-    });
+  captureQaScreenshot(page, {
+    path: `${SHOTS}/${name}`,
+    type: 'jpeg',
+    quality: 82,
+  }).then(() => {
+    console.log(`  shot ${name} — ${caption}`);
+  });
 
 const view = (city) =>
   `${BASE}/?welcome=0#lat=${city.lat}&lon=${city.lon}&alt=600&heading=${city.heading}&pitch=-45`;

src/qaChrome.test.mjs

@@ -1,6 +1,10 @@
 import assert from 'node:assert/strict';
 import test from 'node:test';
-import { MACOS_CHROME, chromeExecutablePath } from '../scripts/qa-chrome.mjs';
+import {
+  MACOS_CHROME,
+  chromeExecutablePath,
+  captureQaScreenshot,
+} from '../scripts/qa-chrome.mjs';
 
 test('gates keep macOS Chrome where it is installed', () => {
   assert.equal(
@@ -25,3 +29,54 @@ test('an explicit executable path wins', () => {
     'C:\\Chrome\\chrome.exe',
   );
 });
+
+test('screenshots restore minimized test windows before capture and detach their session', async () => {
+  const calls = [];
+  const session = {
+    send: async (method, params) => {
+      calls.push([method, params]);
+      return { windowId: 7, bounds: { windowState: 'minimized' } };
+    },
+    detach: async () => calls.push(['detach']),
+  };
+  const page = {
+    createCDPSession: async () => session,
+    bringToFront: async () => calls.push(['front']),
+    screenshot: async (options) => {
+      calls.push(['capture', options]);
+      return 'pixels';
+    },
+  };
+  assert.equal(
+    await captureQaScreenshot(page, { path: 'proof.png' }),
+    'pixels',
+  );
+  assert.deepEqual(
+    calls.map((c) => c[0]),
+    [
+      'Browser.getWindowForTarget',
+      'Browser.setWindowBounds',
+      'front',
+      'detach',
+      'capture',
+    ],
+  );
+  assert.deepEqual(calls[1][1], {
+    windowId: 7,
+    bounds: { windowState: 'normal' },
+  });
+});
+
+test('headless capture does not manipulate a native window', async () => {
+  const options = { path: 'proof.png' };
+  const page = {
+    screenshot: async (supplied) => {
+      assert.equal(supplied, options);
+      return 'pixels';
+    },
+  };
+  assert.equal(
+    await captureQaScreenshot(page, options, { headful: false }),
+    'pixels',
+  );
+});