ERROR [karma]: TypeError: Cannot read property 'unmask' of undefined

gyw@gyw:~/sda1/code/exercise/vue-cli-test-karma$ npm run unit

> [email protected] unit /home/gyw/sda1/code/exercise/vue-cli-test-karma
> cross-env BABEL_ENV=test karma start test/unit/karma.conf.js --single-run

27 04 2018 10:33:03.405:INFO [karma]: Karma v1.7.1 server started at http://0.0.0.0:9876/
27 04 2018 10:33:03.406:INFO [launcher]: Launching browser PhantomJS with unlimited concurrency
27 04 2018 10:33:03.414:INFO [launcher]: Starting browser PhantomJS
27 04 2018 10:33:03.523:ERROR [karma]: TypeError: Cannot read property 'unmask' of undefined
    at Receiver.unmask (/home/gyw/sda1/code/exercise/vue-cli-test-karma/node_modules/engine.io/node_modules/ws/lib/Receiver.js:306:47)
    at Receiver.finish (/home/gyw/sda1/code/exercise/vue-cli-test-karma/node_modules/engine.io/node_modules/ws/lib/Receiver.js:505:25)
    at Receiver.expectHandler (/home/gyw/sda1/code/exercise/vue-cli-test-karma/node_modules/engine.io/node_modules/ws/lib/Receiver.js:493:33)
    at Receiver.add (/home/gyw/sda1/code/exercise/vue-cli-test-karma/node_modules/engine.io/node_modules/ws/lib/Receiver.js:103:24)
    at Socket.realHandler (/home/gyw/sda1/code/exercise/vue-cli-test-karma/node_modules/engine.io/node_modules/ws/lib/WebSocket.js:825:20)
    at emitOne (events.js:116:13)
    at Socket.emit (events.js:211:7)
    at addChunk (_stream_readable.js:263:12)
    at readableAddChunk (_stream_readable.js:250:11)
    at Socket.Readable.push (_stream_readable.js:208:10)
    at TCP.onread (net.js:607:20)
npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! [email protected] unit: `cross-env BABEL_ENV=test karma start test/unit/karma.conf.js --single-run`
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the [email protected] unit script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.

npm ERR! A complete log of this run can be found in:
npm ERR!     /home/gyw/.npm/_logs/2018-04-27T02_33_03_550Z-debug.log

{
  "scripts": {
    "dev": "webpack-dev-server --inline --progress --config build/webpack.dev.conf.js",
    "start": "npm run dev",
    "unit": "cross-env BABEL_ENV=test karma start test/unit/karma.conf.js --single-run",
    "e2e": "node test/e2e/runner.js",
    "test": "npm run unit && npm run e2e",
    "lint": "eslint --ext .js,.vue src test/unit test/e2e/specs",
    "build": "node build/build.js",
    "server": "node build/server.js"
  },
  "dependencies": {
    "vue": "^2.5.2",
    "vue-router": "^3.0.1"
  },
  "devDependencies": {
    "autobahn": "^18.3.2",
    "autoprefixer": "^7.1.2",
    "babel-core": "^6.22.1",
    "babel-eslint": "^8.2.1",
    "babel-helper-vue-jsx-merge-props": "^2.0.3",
    "babel-loader": "^7.1.1",
    "babel-plugin-istanbul": "^4.1.1",
    "babel-plugin-syntax-jsx": "^6.18.0",
    "babel-plugin-transform-runtime": "^6.22.0",
    "babel-plugin-transform-vue-jsx": "^3.5.0",
    "babel-preset-env": "^1.3.2",
    "babel-preset-stage-2": "^6.22.0",
    "babel-register": "^6.22.0",
    "chai": "^4.1.2",
    "chalk": "^2.0.1",
    "chromedriver": "^2.27.2",
    "copy-webpack-plugin": "^4.0.1",
    "cross-env": "^5.0.1",
    "cross-spawn": "^5.0.1",
    "css-loader": "^0.28.0",
    "eslint": "^4.15.0",
    "eslint-config-standard": "^10.2.1",
    "eslint-friendly-formatter": "^3.0.0",
    "eslint-loader": "^1.7.1",
    "eslint-plugin-import": "^2.7.0",
    "eslint-plugin-node": "^5.2.0",
    "eslint-plugin-promise": "^3.4.0",
    "eslint-plugin-standard": "^3.0.1",
    "eslint-plugin-vue": "^4.0.0",
    "extract-text-webpack-plugin": "^3.0.0",
    "file-loader": "^1.1.4",
    "friendly-errors-webpack-plugin": "^1.6.1",
    "html-webpack-plugin": "^2.30.1",
    "inject-loader": "^3.0.0",
    "karma": "^2.0.2",
    "karma-coverage": "^1.1.1",
    "karma-mocha": "^1.3.0",
    "karma-phantomjs-launcher": "^1.0.4",
    "karma-phantomjs-shim": "^1.5.0",
    "karma-sinon-chai": "^1.3.4",
    "karma-sourcemap-loader": "^0.3.7",
    "karma-spec-reporter": "0.0.32",
    "karma-webpack": "^3.0.0",
    "mocha": "^5.1.1",
    "nightwatch": "^0.9.12",
    "node-notifier": "^5.1.2",
    "optimize-css-assets-webpack-plugin": "^3.2.0",
    "ora": "^1.2.0",
    "phantomjs-prebuilt": "^2.1.14",
    "portfinder": "^1.0.13",
    "postcss-import": "^11.0.0",
    "postcss-loader": "^2.0.8",
    "postcss-url": "^7.2.1",
    "rimraf": "^2.6.0",
    "selenium-server": "^3.0.1",
    "semver": "^5.3.0",
    "shelljs": "^0.7.6",
    "sinon": "^4.0.0",
    "sinon-chai": "^2.8.0",
    "uglifyjs-webpack-plugin": "^1.1.1",
    "url-loader": "^0.5.8",
    "vue-loader": "^13.3.0",
    "vue-style-loader": "^3.0.1",
    "vue-template-compiler": "^2.5.2",
    "webpack": "^3.6.0",
    "webpack-bundle-analyzer": "^2.9.0",
    "webpack-dev-server": "^2.9.1",
    "webpack-merge": "^4.1.0",
    "ws": "^5.1.1"
  },
  "engines": {
    "node": ">= 6.0.0",
    "npm": ">= 3.0.0"
  },
  "browserslist": [
    "> 1%",
    "last 2 versions",
    "not ie <= 8"
  ]
}

npm install 
karma@latest 
karma-coverage@latest 
karma-mocha@latest 
karma-phantomjs-launcher@latest 
karma-phantomjs-shim@latest 
karma-sinon-chai@latest 
karma-sourcemap-loader@latest 
karma-spec-reporter@latest 
karma-webpack@latest 
mocha@latest 
ws@latest  -D