Test: Add integration test with karma-qunit

This avoids regressing any APIs that karma-qunit uses to detect
or report failure details, prior to merging or releasing any
changes.

test/integration/karma-qunit.js

@@ -0,0 +1,66 @@
+const cp = require('child_process');
+const path = require('path');
+const DIR = path.join(__dirname, 'karma-qunit');
+
+function normalize (str) {
+  return str
+    .replace(/^.*:INFO/gm, 'INFO')
+    .replace(/(Karma|Firefox) \S+/g, '$1')
+    .replace(/(Firefox) \([^)]*\)/g, '$1')
+    .replace(/(started at|on socket|SUCCESS) .*$/gm, '$1')
+    .replace(/^\s+/gm, '  ');
+}
+
+QUnit.module('karma-qunit', {
+  before: () => {
+    // Need --legacy-peer-deps under npm 7 for "file:" override in package.json.
+    // Once CI and dev environments are on npm 8, consider using native "overrides".
+    cp.execSync('npm install --prefer-offline --no-audit --no-dev --legacy-peer-deps', { cwd: DIR, encoding: 'utf8' });
+  }
+});
+
+QUnit.test('passing test', assert => {
+  const expected = `
+INFO [karma-server]: Karma server started at
+INFO [launcher]: Launching browsers FirefoxHeadless with concurrency unlimited
+INFO [launcher]: Starting browser FirefoxHeadless
+INFO [Firefox]: Connected on socket
+...
+Firefox: Executed 3 of 3 SUCCESS
+`.trim();
+  const actual = normalize(
+    cp.execSync('npm test', { cwd: DIR, env: { PATH: process.env.PATH }, encoding: 'utf8' })
+  );
+  assert.pushResult({ result: actual.includes(expected), actual, expected });
+});
+
+QUnit.test.each('failing test', {
+  assert: ['fail-assert.js', `
+Firefox  example FAILED
+  some message
+  Expected: true
+  Actual: false
+  @fail-assert.js:2:10`
+  ],
+  'global-error': ['fail-global-error.js', `
+Firefox  example FAILED
+  Died on test #1: boom is not defined
+  @fail-global-error.js:1:7`
+  ]
+}, (assert, [file, expected]) => {
+  try {
+    const ret = cp.execSync('npm test', {
+      cwd: DIR,
+      env: {
+        PATH: process.env.PATH,
+        KARMA_FILES: file
+      },
+      encoding: 'utf8'
+    });
+    assert.equal(ret, null);
+  } catch (e) {
+    const actual = normalize(e.stdout);
+    assert.pushResult({ result: actual.includes(expected), actual, expected });
+    assert.true(e.status > 0, 'non-zero exit code');
+  }
+});

test/integration/karma-qunit/fail-assert.js

@@ -0,0 +1,3 @@
+QUnit.test('example', function (assert) {
+  assert.true(false, 'some message');
+});

test/integration/karma-qunit/fail-global-error.js

@@ -0,0 +1,5 @@
+QUnit.test('example', function (assert) {
+  // eslint-disable-next-line no-undef
+  boom();
+  assert.true(true);
+});

test/integration/karma-qunit/karma.conf.js

@@ -0,0 +1,16 @@
+/* eslint-env node */
+
+module.exports = function (config) {
+  config.set({
+    browsers: [
+      'FirefoxHeadless'
+    ],
+    frameworks: ['qunit'],
+    files: [
+      process.env.KARMA_FILES || 'pass-*.js'
+    ],
+    autoWatch: false,
+    singleRun: true,
+    reporters: ['dots']
+  });
+};

test/integration/karma-qunit/package.json

@@ -0,0 +1,13 @@
+{
+  "private": true,
+  "dependencies": {
+    "karma": "^6.3.18",
+    "karma-chrome-launcher": "^3.1.1",
+    "karma-firefox-launcher": "^2.1.2",
+    "karma-qunit": "^4.1.2",
+    "qunit": "file:../../.."
+  },
+  "scripts": {
+    "test": "karma start --no-colors"
+  }
+}

test/integration/karma-qunit/pass-basic.js

@@ -0,0 +1,9 @@
+QUnit.test('example 1', function (assert) {
+  assert.true(true, 'x');
+});
+QUnit.test('example 2', function (assert) {
+  assert.true(true, 'y');
+});
+QUnit.test('example 3', function (assert) {
+  assert.true(true, 'z');
+});