wct.conf.json

{
  "suites": ["tests/runner.html"],
  "clientOptions": {
    "environmentImports": []
  },
  "npm": true,
  "plugins": {
    "local": {
      "browserOptions": {
        "chrome": [
          "headless",
          "disable-gpu",
          "no-sandbox"
        ],
        "firefox": [
          "-headless"
        ]
      }
    }
  }
}