Ionic unit testing: webpack version

Question

I've been trying to set up a testing example according to the common guidelines: Testing in Ionic, Ionic GitHub Example

My project's package.json:

{
  "name": "starter-with-testing",
  "version": "0.0.1",
  "author": "Ionic Framework",
  "homepage": "http://ionicframework.com/",
  "private": true,
  "scripts": {
    "clean": "ionic-app-scripts clean",
    "build": "ionic-app-scripts build",
    "lint": "ionic-app-scripts lint",
    "ionic:build": "ionic-app-scripts build",
    "ionic:serve": "ionic-app-scripts serve",
    "test": "karma start ./test-config/karma.conf.js"
  },
  "dependencies": {
    "@angular/animations": "5.2.11",
    "@angular/common": "5.2.11",
    "@angular/compiler": "5.2.11",
    "@angular/compiler-cli": "5.2.11",
    "@angular/core": "5.2.11",
    "@angular/forms": "5.2.11",
    "@angular/http": "5.2.11",
    "@angular/platform-browser": "5.2.11",
    "@angular/platform-browser-dynamic": "5.2.11",
    "@ionic-native/core": "4.7.0",
    "@ionic-native/splash-screen": "4.7.0",
    "@ionic-native/status-bar": "4.7.0",
    "@ionic/storage": "2.1.3",
    "ionic-angular": "3.9.2",
    "ionicons": "3.0.0",
    "rxjs": "5.5.11",
    "sw-toolbox": "3.6.0",
    "zone.js": "0.8.26"
  },
  "devDependencies": {
    "@ionic/app-scripts": "^3.1.10",
    "@types/jasmine": "^2.8.8",
    "@types/node": "^10.3.4",
    "angular2-template-loader": "^0.6.2",
    "html-loader": "^0.5.5",
    "istanbul-instrumenter-loader": "^3.0.1",
    "jasmine": "^3.1.0",
    "jasmine-spec-reporter": "^4.2.1",
    "karma": "^2.0.3",
    "karma-chrome-launcher": "^2.2.0",
    "karma-coverage-istanbul-reporter": "^2.0.1",
    "karma-jasmine": "^1.1.2",
    "karma-jasmine-html-reporter": "^1.1.0",
    "karma-sourcemap-loader": "^0.3.7",
    "karma-webpack": "^3.0.0",
    "null-loader": "^0.1.1",
    "protractor": "^5.3.2",
    "ts-loader": "^4.4.1",
    "ts-node": "^6.1.2",
    "typescript": "~2.6.2"
  },
  "description": "An Ionic project"
}

Attempt at $ npm test results in an error:

Chrome 67.0.3396 (Linux 0.0.0) ERROR
{
"message": "An error was thrown in afterAll\nUncaught Error: Module build failed: Error: You may be using an old version of webpack; please check you're using at least version 4\n    at successfulTypeScriptInstance (/home/alexey/spaces/cordova/starter-with-testing/node_modules/ts-loader/dist/instances.js:168:15)\n    at Object.getTypeScriptInstance (/home/alexey/spaces/cordova/starter-with-testing/node_modules/ts-loader/dist/instances.js:51:12)\n    at Object.loader (/home/alexey/spaces/cordova/starter-with-testing/node_modules/ts-loader/dist/index.js:16:41)"

That is, webpack 4.x required. Indeed,

$ npm list webpack
[email protected] /home/alexey/spaces/cordova/starter-with- 
testing
└─┬ @ionic/[email protected]
  └── [email protected]

What am I supposed to do?

UPD:

I've got It looks like your post is mostly code; please add some more details. fatal error. Your question couldn't be submitted.

I'm really at a loss about more details. There is a dependency hell; please, help. I'll humbly submit whatever additional details you ask.

Answer 1

I had the same problem, and fixed it by downgrading my ts-loader and ts-node to the versions used in the ionic-unit-testing-example repository. I.e. in package.json:

{
    //...
    "devDependencies": {
        //...
        "ts-loader": "^3.0.3",
        "ts-node": "^3.0.2",
        //...
    }
    //...
}

It's ts-loader that's complaining, so I'm not sure if the ts-node downgrade is actually required.