test: harden Windows CI readiness checks

TESTING.md

@@ -18,6 +18,39 @@ vpr test:all
 `vpr test:all` formats, lints, builds, typechecks, and tests the merged monorepo. Investigate slow
 or hanging tests when they occur instead of routinely increasing timeouts.
 
+## Browser readiness and Windows CI
+
+Use `waitForIslandsHydrated` from `test/browser-helpers.ts` before asserting island state or
+interacting with islands. Pass the expected minimum count when checking a multi-island fixture.
+Each island imports and hydrates independently, so a selector matching one hydrated island does
+not establish that its siblings are ready. The helper rejects empty or partially hydrated pages;
+`packages/void/test/integration/browser-helpers.test.ts` covers these cases.
+
+For SPA navigation, wait for a client readiness signal before setting the document marker and
+clicking. The Nuxt and SvelteKit playgrounds expose `h1[data-hydrated="true"]` after client startup.
+`networkidle` and server-rendered HTML do not establish router readiness. Keep the document-marker
+assertion so a full reload still fails the test. These suites attach recent browser console,
+navigation, failed-request, HMR, and dev-server output to failures.
+
+Give real subprocess tests a measured, suite-local timeout. The Drizzle drift suite can launch
+three processes per case and uses 30 seconds on Windows and 10 seconds elsewhere. Ordinary unit
+tests retain their default timeout. `waitForServer` already scales its timeout on Windows;
+callers should pass an unscaled value and leave enough hook time for that wait and setup.
+
+Windows integration tests also use `maxConcurrency: 2`. `maxWorkers` caps files, not concurrent
+tests inside each file: two CI workers with Vitest's default concurrency of five can open ten
+isolated browser contexts at once. The Windows cap reduces that to four without serializing
+files or changing Linux/macOS concurrency. Do not retry browser navigation to hide
+`ERR_NO_BUFFER_SPACE`; it reports a Windows socket resource failure, not a readiness timeout.
+
+The Windows setup hook prints one resource snapshot per integration file at the first failed
+test, before suite teardown. It records memory, the largest processes, dynamic TCP port ranges,
+and connection counts by state/PID. Collection is read-only, limited to ten seconds and 64 KiB,
+and retains partial output if it fails. Concurrent failures share the snapshot. It does not log
+environment variables, process command lines, or remote addresses, and does not replace the
+original test failure. Use this evidence to distinguish port, queue, and memory pressure rather
+than assuming every socket error is port exhaustion.
+
 ## Native Cloudflare live E2E tests
 
 Live tests are opt-in. They provision or update real resources and can write data, enqueue messages,

packages/react/test/integration/react-pages-client.test.ts

@@ -4,6 +4,7 @@ import spawn from 'cross-spawn';
 import { join } from 'pathslash';
 import { chromium, type Browser, type Page } from 'playwright';
 import { describe, expect, it, beforeAll, afterAll } from 'vite-plus/test';
+import { waitForIslandsHydrated } from '../../../../test/browser-helpers.ts';
 import { getPort, waitForServer, killChild } from '../../../../test/integration-helpers.ts';
 
 declare global {
@@ -914,7 +915,7 @@ function registerIslandTests(getBase: () => string) {
     const page = await newPage();
     try {
       await page.goto(BASE + '/blog');
-      await page.waitForSelector('[data-island][data-hydrated="true"]');
+      await waitForIslandsHydrated(page, 2);
 
       const islands = await page.$$eval('[data-island]', (els) =>
         els.map((el) => ({
@@ -936,7 +937,7 @@ function registerIslandTests(getBase: () => string) {
     const page = await newPage();
     try {
       await page.goto(BASE + '/blog');
-      await page.waitForSelector('[data-island][data-hydrated="true"]');
+      await waitForIslandsHydrated(page);
 
       const countBefore = await page.textContent('[data-testid="count"]');
       expect(countBefore).toBe('Count: 0');
@@ -957,7 +958,7 @@ function registerIslandTests(getBase: () => string) {
     const page = await newPage();
     try {
       await page.goto(BASE + '/blog');
-      await page.waitForSelector('[data-island][data-hydrated="true"]');
+      await waitForIslandsHydrated(page);
 
       await page.click('button:has-text("Add Post")');
       await page.waitForFunction(() => document.body.textContent?.includes('Title is required'));
@@ -974,7 +975,7 @@ function registerIslandTests(getBase: () => string) {
     const page = await newPage();
     try {
       await page.goto(BASE + '/blog');
-      await page.waitForSelector('[data-island][data-hydrated="true"]');
+      await waitForIslandsHydrated(page);
 
       await page.fill('input:near(:text("Title:"))', 'New Post');
       await page.fill('textarea:near(:text("Body:"))', 'Some content');
@@ -1011,7 +1012,7 @@ function registerIslandTests(getBase: () => string) {
       expect(marker).toBeUndefined();
 
       // Islands should be hydrated
-      await page.waitForSelector('[data-island][data-hydrated="true"]');
+      await waitForIslandsHydrated(page);
     } finally {
       await page.context().close();
     }
@@ -1398,7 +1399,7 @@ describe('react-pages client (dev)', () => {
 
     try {
       await page.goto(`${DEV_BASE}/blog`);
-      await page.waitForSelector('[data-island][data-hydrated="true"]');
+      await waitForIslandsHydrated(page);
 
       // Interact to establish client state — count becomes 1
       await page.click("button:has-text('Increment')");

packages/solid/test/integration/solid-pages-playground.test.ts

@@ -4,6 +4,7 @@ import spawn from 'cross-spawn';
 import { join } from 'pathslash';
 import { chromium, type Browser, type Page } from 'playwright';
 import { afterAll, beforeAll, describe, expect, it } from 'vite-plus/test';
+import { waitForIslandsHydrated } from '../../../../test/browser-helpers.ts';
 import { getPort, waitForServer, killChild } from '../../../../test/integration-helpers.ts';
 
 declare global {
@@ -485,13 +486,7 @@ function registerIslandTests(getBase: () => string) {
     const page = await newPage();
     try {
       await page.goto(BASE + '/blog');
-      await page.waitForFunction(() => {
-        const islands = [...document.querySelectorAll('[data-island]')];
-        return (
-          islands.length >= 2 &&
-          islands.every((island) => island.getAttribute('data-hydrated') === 'true')
-        );
-      });
+      await waitForIslandsHydrated(page, 2);
 
       const islands = await page.$$eval('[data-island]', (els) =>
         els.map((el) => ({
@@ -513,7 +508,7 @@ function registerIslandTests(getBase: () => string) {
     const page = await newPage();
     try {
       await page.goto(BASE + '/blog');
-      await page.waitForSelector('[data-island][data-hydrated="true"]');
+      await waitForIslandsHydrated(page);
 
       const countBefore = await page.textContent('[data-testid="count"]');
       expect(countBefore).toBe('Count: 0');
@@ -534,7 +529,7 @@ function registerIslandTests(getBase: () => string) {
     const page = await newPage();
     try {
       await page.goto(BASE + '/blog');
-      await page.waitForSelector('[data-island][data-hydrated="true"]');
+      await waitForIslandsHydrated(page);
 
       await page.click('button:has-text("Add Post")');
       // The first action can include a cold worker compile under full-suite load. Keep the normal
@@ -553,7 +548,7 @@ function registerIslandTests(getBase: () => string) {
     const page = await newPage();
     try {
       await page.goto(BASE + '/blog');
-      await page.waitForSelector('[data-island][data-hydrated="true"]');
+      await waitForIslandsHydrated(page);
 
       await page.fill('input:near(:text("Title:"))', 'New Post');
       await page.fill('textarea:near(:text("Body:"))', 'Some content');
@@ -590,7 +585,7 @@ function registerIslandTests(getBase: () => string) {
       expect(marker).toBeUndefined();
 
       // Islands should be hydrated
-      await page.waitForSelector('[data-island][data-hydrated="true"]');
+      await waitForIslandsHydrated(page);
     } finally {
       await page.context().close();
     }
@@ -884,7 +879,7 @@ describe('solid-pages client (dev)', () => {
 
     try {
       await page.goto(`${DEV_BASE}/blog`);
-      await page.waitForSelector('[data-island][data-hydrated="true"]');
+      await waitForIslandsHydrated(page);
 
       // Interact to establish client state — count becomes 1
       await page.click("button:has-text('Increment')");

packages/svelte/test/integration/svelte-pages-client.test.ts

@@ -4,6 +4,7 @@ import spawn from 'cross-spawn';
 import { join } from 'pathslash';
 import { chromium, type Browser, type Page } from 'playwright';
 import { describe, expect, it, beforeAll, afterAll } from 'vite-plus/test';
+import { waitForIslandsHydrated } from '../../../../test/browser-helpers.ts';
 import { getPort, waitForServer, killChild } from '../../../../test/integration-helpers.ts';
 
 declare global {
@@ -26,16 +27,6 @@ let PREVIEW_BASE: string;
 
 let browser: Browser;
 
-async function waitForIslandsHydrated(page: Page) {
-  await page.waitForFunction(() => {
-    const islands = Array.from(document.querySelectorAll('[data-island]'));
-    return (
-      islands.length > 0 &&
-      islands.every((island) => island.getAttribute('data-hydrated') === 'true')
-    );
-  });
-}
-
 beforeAll(async () => {
   browser = await chromium.launch();
 });
@@ -461,7 +452,7 @@ function registerIslandTests(getBase: () => string) {
     const page = await newPage();
     try {
       await page.goto(BASE + '/blog');
-      await waitForIslandsHydrated(page);
+      await waitForIslandsHydrated(page, 2);
 
       const islands = await page.$$eval('[data-island]', (els) =>
         els.map((el) => ({

packages/void/test/integration/browser-helpers.test.ts

@@ -0,0 +1,38 @@
+import { chromium, type Browser } from 'playwright';
+import { afterAll, beforeAll, expect, it } from 'vite-plus/test';
+import { waitForIslandsHydrated } from '../../../../test/browser-helpers.ts';
+
+let browser: Browser;
+
+beforeAll(async () => {
+  browser = await chromium.launch();
+});
+
+afterAll(async () => {
+  await browser?.close();
+});
+
+it('waits for the expected islands and every independent hydration', async () => {
+  const page = await browser.newPage();
+  try {
+    // Empty SSR output must not make an all-elements check pass vacuously.
+    await page.setContent('<main></main>');
+    await expect(waitForIslandsHydrated(page, 1, 500)).rejects.toThrow('Timeout');
+
+    await page.setContent('<div data-island="counter" data-hydrated="true"></div>');
+    await expect(waitForIslandsHydrated(page, 2, 500)).rejects.toThrow('Timeout');
+
+    await page.setContent(
+      '<div data-island="counter" data-hydrated="true"></div><div data-island="form"></div>',
+    );
+    // The old any-island selector returned here while the form still had no event handlers.
+    await expect(waitForIslandsHydrated(page, 2, 500)).rejects.toThrow('Timeout');
+
+    await page.locator('[data-island="form"]').evaluate((el) => {
+      el.setAttribute('data-hydrated', 'true');
+    });
+    await waitForIslandsHydrated(page, 2);
+  } finally {
+    await page.close();
+  }
+});

packages/void/test/integration/nuxt.test.ts

@@ -3,6 +3,7 @@ import { existsSync, readFileSync, rmSync } from 'node:fs';
 import spawn from 'cross-spawn';
 import { join } from 'pathslash';
 import { afterAll, beforeAll, describe, expect, it } from 'vite-plus/test';
+import { collectBrowserDiagnostics } from '../../../../test/browser-helpers.ts';
 import { getPort, waitForServer, killChild } from '../../../../test/integration-helpers.ts';
 
 const ROOT = join(import.meta.dirname, '..', '..', '..', '..');
@@ -38,7 +39,7 @@ describe(
   'playground/nuxt dev',
   () => {
     let child: ReturnType<typeof spawn>;
-    let stderr = '';
+    let serverOutput = '';
 
     beforeAll(
       async () => {
@@ -72,14 +73,23 @@ describe(
           },
         );
 
-        child.stderr!.on('data', (chunk: Buffer) => {
-          stderr += String(chunk);
-        });
-
-        const serverTimeout = process.platform === 'win32' ? 60_000 : 30_000;
-        await waitForServer(DEV_BASE, serverTimeout);
+        const recordOutput = (chunk: Buffer) => {
+          serverOutput = (serverOutput + String(chunk)).slice(-20_000);
+        };
+        child.stdout!.on('data', recordOutput);
+        child.stderr!.on('data', recordOutput);
+
+        try {
+          await waitForServer(DEV_BASE, 30_000, {
+            expectStatus: 200,
+            expectBody: 'Nuxt + Void',
+            isAlive: () => child.exitCode === null && child.signalCode === null,
+          });
+        } catch (error) {
+          throw new Error(`Nuxt failed to start:\n${serverOutput}`, { cause: error });
+        }
       },
-      process.platform === 'win32' ? 75_000 : 45_000,
+      process.platform === 'win32' ? 120_000 : 45_000,
     );
 
     afterAll(async () => {
@@ -110,10 +120,13 @@ describe(
     it('navigates to smoke route via SPA from home page', async () => {
       const { chromium } = await import('playwright');
       const browser = await chromium.launch();
+      let diagnostics = () => '';
       try {
         const page = await browser.newPage();
+        diagnostics = collectBrowserDiagnostics(page);
         await page.goto(DEV_BASE);
-        await page.waitForLoadState('networkidle');
+        // SSR and network inactivity do not mean Nuxt has installed its router yet.
+        await page.waitForSelector('h1[data-hydrated="true"]');
 
         // Mark the document to detect full page reloads
         await page.evaluate(() => {
@@ -134,6 +147,8 @@ describe(
         const kvValue = await page.textContent('[data-testid="kv-value"]');
         expect(d1User).toBe('Alice');
         expect(kvValue).toBe('ok');
+      } catch (error) {
+        throw new Error(`${diagnostics()}\nDev server:\n${serverOutput}`, { cause: error });
       } finally {
         await browser.close();
       }

packages/void/test/integration/sveltekit.test.ts

@@ -3,6 +3,7 @@ import { existsSync, readFileSync, rmSync, writeFileSync } from 'node:fs';
 import spawn from 'cross-spawn';
 import { join } from 'pathslash';
 import { afterAll, beforeAll, describe, expect, it } from 'vite-plus/test';
+import { collectBrowserDiagnostics } from '../../../../test/browser-helpers.ts';
 import { getPort, waitForServer, killChild } from '../../../../test/integration-helpers.ts';
 
 const ROOT = join(import.meta.dirname, '..', '..', '..', '..');
@@ -33,7 +34,7 @@ describe('playground/sveltekit build', () => {
 
 describe('playground/sveltekit dev', () => {
   let child: ReturnType<typeof spawn>;
-  let stderr = '';
+  let serverOutput = '';
 
   beforeAll(async () => {
     const pg = join(ROOT, PLAYGROUND);
@@ -66,19 +67,29 @@ describe('playground/sveltekit dev', () => {
       },
     );
 
-    child.stderr!.on('data', (chunk: Buffer) => {
-      stderr += String(chunk);
-    });
+    const recordOutput = (chunk: Buffer) => {
+      serverOutput = (serverOutput + String(chunk)).slice(-20_000);
+    };
+    child.stdout!.on('data', recordOutput);
+    child.stderr!.on('data', recordOutput);
 
-    await waitForServer(DEV_BASE, 20_000);
+    try {
+      await waitForServer(DEV_BASE, 30_000, {
+        expectStatus: 200,
+        expectBody: 'SvelteKit + Void',
+        isAlive: () => child.exitCode === null && child.signalCode === null,
+      });
+    } catch (error) {
+      throw new Error(`SvelteKit failed to start:\n${serverOutput}`, { cause: error });
+    }
   });
 
   afterAll(async () => {
     if (child) {
       await killChild(child);
     }
-    if (stderr.includes('error when starting dev server')) {
-      throw new Error(stderr);
+    if (serverOutput.includes('error when starting dev server')) {
+      throw new Error(serverOutput);
     }
   });
 
@@ -104,10 +115,13 @@ describe('playground/sveltekit dev', () => {
   it('navigates to smoke route via SPA from home page', async () => {
     const { chromium } = await import('playwright');
     const browser = await chromium.launch();
+    let diagnostics = () => '';
     try {
       const page = await browser.newPage();
+      diagnostics = collectBrowserDiagnostics(page);
       await page.goto(DEV_BASE);
-      await page.waitForLoadState('networkidle');
+      // Wait for client mounting before clicking the server-rendered link.
+      await page.waitForSelector('h1[data-hydrated="true"]');
 
       // Mark the document to detect full page reloads
       await page.evaluate(() => {
@@ -128,6 +142,8 @@ describe('playground/sveltekit dev', () => {
       const kvValue = await page.textContent('[data-testid="kv-value"]');
       expect(d1User).toBe('Alice');
       expect(kvValue).toBe('ok');
+    } catch (error) {
+      throw new Error(`${diagnostics()}\nDev server:\n${serverOutput}`, { cause: error });
     } finally {
       await browser.close();
     }