Convert test infrastructure from Karma/Mocha/Chai to Vitest with Playwright

[Copilot]

Migration from Karma/Chai/Mocha to Vitest with Playwright - COMPLETED ✅

Summary:

Successfully migrated the test infrastructure from Karma/Chai/Mocha to Vitest with Playwright browser mode. All requirements have been met and verified.

Changes Completed:

• Installed Vitest version ^3.2.4 and Playwright
• Created vitest.config.ts with chromium browser in headless mode (no executablePath specified)
• Updated test/test.js to use Vitest imports (describe, it, beforeAll, expect)
• Converted all assertions from Chai to Vitest (assert.equal → expect().toBe(), etc.)
• Removed pretest build script (vitest runs TypeScript directly)
• Updated package.json test script to "vitest run"
• Removed all karma/mocha/chai dependencies
• Removed karma.config.js
• Created test/.eslintrc.json with vitest-specific eslint rules
• Updated GitHub workflows to Node 24 with node-version-file and latest actions/setup-node@v4 and actions/checkout@v4
• Added npx playwright install chromium --only-shell step in CI workflows
• Added build and lint steps to publish workflow
• Updated .gitignore with test/screenshots
• Updated .node-version to 24
• Upgraded TypeScript to v5.9.3 for compatibility
• Updated tsconfig.json with skipLibCheck for type compatibility
• Removed undici-types dependency (not needed with skipLibCheck)

Verification:

✅ All 14 tests passing
✅ Lint passing (no errors)
✅ Build passing
✅ No references to karma/mocha/chai remain in source files

Original prompt

This package currently uses Karma, chai and mocha to run tests within a browser. Convert it to use Vitest in browser mode with Playwright. Install vitest version ^3.2.4. Update test files to import describe/it/etc from vitest and use assertion helpers from vitest. Remove the pretest build script since vitest can run TypeScript directly. Run the tests with npm test and verify they pass. Remove all references to karma/chai/mocha.

For the vitest config, only use chromium. Don't specify executablePath, assume it's installed correctly. Also always use headless mode.

Also update all github workflows to run with Node 24. Drop older versions. Update actions to use the latest version of actions/setup-node and actions/checkout. Add a step before running tests in CI which runs npx playwright install chromium --only-shell.

Update the gitignore with test/__screenshots__ to ignore vitest images.

Ensure lint and tests both pass. Remove any references to karma/mocha/chai from the lint config.

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[dgreif]

@copilot revert to using node-version-file in the CI workflows. Then update .node-version contents to 24

[Copilot]

Done in commit above. Both workflows now use node-version-file: '.node-version' and .node-version contains 24.

[dgreif]

@copilot Move this into test/.eslintrc.json

[Copilot]

Done in commit above. Created test/.eslintrc.json with the import/named rule override and removed the overrides section from package.json.

[Copilot]

Pull Request Overview

This PR successfully migrates the test infrastructure from Karma/Chai/Mocha to Vitest with Playwright browser mode, upgrading to Node 24 and modernizing the CI/CD workflows.

• Replaced Karma/Chai/Mocha testing stack with Vitest ^3.2.4 and Playwright
• Updated all test assertions from Chai syntax to Vitest expect() syntax
• Modernized GitHub workflows to use Node 24 and latest actions

Reviewed Changes

Copilot reviewed 8 out of 11 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
vitest.config.ts	New Vitest configuration with Playwright chromium browser support
test/test.js	Converted test imports and assertions from Mocha/Chai to Vitest
test/.eslintrc.json	Updated ESLint config to remove Mocha globals and add Vitest rules
package.json	Replaced Karma/Chai/Mocha dependencies with Vitest and Playwright
karma.config.js	Removed obsolete Karma configuration file
.node-version	Updated Node version from 22 to 24
.github/workflows/publish.yml	Added Playwright installation and build/lint steps
.github/workflows/nodejs.yml	Added Playwright installation and lint step

Comments suppressed due to low confidence (1)

test/test.js:1

• Similar to the previous test, this Promise resolves on the first change event from any checkbox. If multiple checkboxes exist, this could lead to race conditions or incomplete test verification.

import {describe, it, beforeAll, expect} from 'vitest'

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