From 62ff9fc2e89deb5aeeab2d7b01516f36cd1e2da3 Mon Sep 17 00:00:00 2001
From: Benny Powers <web@bennypowers.com>
Date: Mon, 1 Jun 2026 21:30:29 +0300
Subject: [PATCH] refactor(test-runner-visual-regression): migrate tests to
 node:test

Replace mocha globals and chai assertions with node:test and
node:assert/strict.

- `../src/*.js` -> `../dist/*.js`
- `__dirname` -> `import.meta.dirname`
- `this.timeout(20000)` -> `{ timeout: 20000 }` on describe
- `expect(x).to.equal(y)` -> `assert.equal(x, y)`
- `expect(x).to.include(y)` -> `assert.ok(x.includes(y))`
- Add `--experimental-strip-types` for CI compat

Assisted-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
---
 .../package.json                              |  4 +-
 .../test/visualRegressionPlugin.test.ts       | 41 ++++++++++---------
 2 files changed, 24 insertions(+), 21 deletions(-)

diff --git a/packages/test-runner-visual-regression/package.json b/packages/test-runner-visual-regression/package.json
index 3db4aae8db..9a2f070f1d 100644
--- a/packages/test-runner-visual-regression/package.json
+++ b/packages/test-runner-visual-regression/package.json
@@ -30,8 +30,8 @@
   },
   "scripts": {
     "build": "tsc",
-    "test:node": "mocha test/**/*.test.ts --require ts-node/register --reporter dot",
-    "test:watch": "mocha test/**/*.test.ts --require ts-node/register --watch --watch-files src,test"
+    "test:node": "node --experimental-strip-types --test --test-force-exit test/**/*.test.ts",
+    "test:watch": "node --experimental-strip-types --test --test-force-exit --watch test/**/*.test.ts"
   },
   "files": [
     "*.d.ts",
diff --git a/packages/test-runner-visual-regression/test/visualRegressionPlugin.test.ts b/packages/test-runner-visual-regression/test/visualRegressionPlugin.test.ts
index fa9606a474..c15e127e71 100644
--- a/packages/test-runner-visual-regression/test/visualRegressionPlugin.test.ts
+++ b/packages/test-runner-visual-regression/test/visualRegressionPlugin.test.ts
@@ -1,18 +1,17 @@
+import { describe, it } from 'node:test';
+import assert from 'node:assert/strict';
 import path from 'path';
 import { runTests } from '@web/test-runner-core/test-helpers';
-import { expect } from 'chai';
 import { chromeLauncher } from '@web/test-runner-chrome';
 
-import { visualRegressionPlugin } from '../src/visualRegressionPlugin.js';
-import { fileExists } from '../src/fs.js';
+import { visualRegressionPlugin } from '../dist/visualRegressionPlugin.js';
+import { fileExists } from '../dist/fs.js';
 import { playwrightLauncher } from '@web/test-runner-playwright';
 
-describe('visualRegressionPlugin', function test() {
-  this.timeout(20000);
-
+describe('visualRegressionPlugin', { timeout: 20000 }, () => {
   it('can run a passing test', async () => {
     await runTests({
-      files: [path.join(__dirname, 'diff-pass-test.js')],
+      files: [path.join(import.meta.dirname, 'diff-pass-test.js')],
       browsers: [
         chromeLauncher(),
         playwrightLauncher({ product: 'firefox' }),
@@ -38,7 +37,7 @@ describe('visualRegressionPlugin', function test() {
   it('can run a failed test', async () => {
     const { sessions } = await runTests(
       {
-        files: [path.join(__dirname, 'diff-fail-test.js')],
+        files: [path.join(import.meta.dirname, 'diff-fail-test.js')],
         browsers: [
           chromeLauncher(),
           playwrightLauncher({ product: 'firefox' }),
@@ -63,18 +62,20 @@ describe('visualRegressionPlugin', function test() {
       { allowFailure: true, reportErrors: false },
     );
 
-    expect(sessions.length).to.equal(3);
+    assert.equal(sessions.length, 3);
 
     for (const session of sessions) {
-      expect(session.passed).to.equal(false);
-      expect(session.testResults!.tests.length).to.equal(1);
-      expect(session.testResults!.tests[0].error!.message).to.include(
-        'Visual diff failed. New screenshot is ',
+      assert.equal(session.passed, false);
+      assert.equal(session.testResults!.tests.length, 1);
+      assert.ok(
+        session.testResults!.tests[0].error!.message.includes(
+          'Visual diff failed. New screenshot is ',
+        ),
       );
-      expect(
+      assert.equal(
         await fileExists(
           path.resolve(
-            __dirname,
+            import.meta.dirname,
             '..',
             'screenshots',
             session.browser.name,
@@ -82,11 +83,12 @@ describe('visualRegressionPlugin', function test() {
             'my-failed-element.png',
           ),
         ),
-      ).to.equal(true);
-      expect(
+        true,
+      );
+      assert.equal(
         await fileExists(
           path.resolve(
-            __dirname,
+            import.meta.dirname,
             '..',
             'screenshots',
             session.browser.name,
@@ -94,7 +96,8 @@ describe('visualRegressionPlugin', function test() {
             'my-failed-element-diff.png',
           ),
         ),
-      ).to.equal(true);
+        true,
+      );
     }
   });
 });