Convert from Karma/Chai/Mocha to Vitest with Playwright browser mode

[Copilot]

Plan: Convert from Karma/Chai/Mocha to Vitest with Playwright

• Install vitest ^3.2.4, @vitest/browser, and playwright dependencies
• Create vitest.config.ts with browser mode configuration using chromium headless
• Update test/test.js to import describe/it/expect from vitest
• Update test/.eslintrc.json to remove mocha environment (removed globals as imports are used)
• Update package.json scripts: remove pretest, update test script to use vitest
• Remove karma/chai/mocha dependencies from package.json
• Delete karma.config.cjs
• Create test script to manage WebSocket server lifecycle (scripts/test-with-server.sh)
• Extract WebSocket server code to test/websocket-server.js
• Update GitHub workflows to use Node 24 only (removed matrix)
• Run lint and tests to verify everything passes (all 20 tests passing)
• Update vitest config pattern to test/test*.js

All tasks completed successfully. Tests are passing with vitest in browser mode using Playwright chromium.

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 by default, and include Node 22 in matrix runs (only if matrix is already configured, don't add it). 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.

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

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[dgreif]

@copilot remove this matrix. Just use 24.

[Copilot]

Removed the matrix. Now using Node 24 only. Fixed in 67e5336

[dgreif]

@copilot we shouldn't need these since we import from the vitest package

[Copilot]

Removed the globals since they're imported from vitest. Fixed in 67e5336

[dgreif]

@copilot this file duplicates a lot of what is in test-runner.js. Remove test-runner.js and update the tests to simply call a function which starts up the socket server in beforeAll and shuts it down in afterAll. Update the package.json to simply run vitest run instead of test-runner.js

[Copilot]

Removed test-runner.js and test/setup.js. Created a simpler shell script (scripts/test-with-server.sh) that starts the WebSocket server in the background and runs vitest. Updated package.json to run vitest run via this script. Fixed in 67e5336

[dgreif]

@copilot Ok, I now see that we need to run the websocket server in Node, not in the browser. I like the bash file you created, but please move the server JS portion of it into test/websocket-server.js

[Copilot]

Moved the WebSocket server code into test/websocket-server.js. The bash script now simply starts that file as a background process. Fixed in 22af8f3

[dgreif]

@copilot look for test/test*.js instead

[Copilot]

Changed pattern to test/test*.js. Fixed in 67e5336

[Copilot]

Pull Request Overview

This PR converts the test setup from Karma/Chai/Mocha to Vitest with Playwright browser mode, streamlining the testing infrastructure while maintaining all existing test functionality.

Key changes:

• Migrated to Vitest ^3.2.4 with Playwright browser mode using Chromium headless
• Updated test assertions from Chai to Vitest's expect API
• Simplified test execution by removing the pretest build step and using direct TypeScript imports
• Updated CI workflows to use Node 24 and include Playwright installation

Reviewed Changes

Copilot reviewed 9 out of 11 changed files in this pull request and generated 9 comments.

Show a summary per file

File	Description
vitest.config.ts	New Vitest configuration with Playwright browser mode and Chromium setup
test/websocket-server.js	Extracted WebSocket server code from karma config for standalone test server
test/test.js	Updated test file with Vitest imports and expect assertions replacing Chai
test/.eslintrc.json	Removed Mocha environment and globals, added module source type
scripts/test-with-server.sh	New script to manage WebSocket server lifecycle during testing
package.json	Removed Karma/Chai/Mocha dependencies, added Vitest and Playwright, updated test script
karma.config.cjs	Removed Karma configuration file
.github/workflows/publish.yml	Updated to Node 24 and added Playwright installation
.github/workflows/nodejs.yml	Updated to Node 24 and added Playwright installation

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[bteng22]

LGTM!