testem.json

{
  "test_page": "./test/mocha-testem.mustache",
  "before_tests": "npm run test:bundle-create",
  "after_tests": "npm run test:bundle-clean",
  "launch_in_ci": [
    "Firefox"
  ],
  "browser_args": {
    "Firefox": [
      "--headless"
    ]
  }
}