webextensions-examples/mocha-client-tests/addon/package.json

{
  "name": "mocha-tests-webextension",
  "version": "1.0.0",
  "description": "Run test inside your addon",
  "main": "background.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "",
  "license": "MPL-2.0",
  "devDependencies": {
    "expect.js": "^0.3.1",
    "mocha": "^3.1.2"
  }
}