How to run mocha and mocha-phantomjs tests from one "npm test" command in node.js?

I like the following:

  "scripts": {
    "test": "npm run test-node && npm run test-browser",
    "test-node": "mocha -R spec ./test/node/index.js",
    "test-browser": "mocha-phantomjs ./test/browser/index.html"}

The && only runs the second if the first passes, and you can run either separately if you want. Note that npm always uses the relative mocha (inside node_modules), not the global one, so there's no harm in just calling mocha and mocha-phantomjs directly. You can be even more efficient with mocha's -b option for bail, which will quit as soon as it encounters an error.

Came here looking for information on configuring npm with karma. @dankohn's answer can be adapted thusly:

"scripts": {
  "test": "npm run test-node && npm run test-browser",
  "test-node": "karma run",
  "test-browser": "karma start --single-run"
}

Hope this helps someone else out.