Karma Test running after executing tests screen goes blank

Question

after running ng test my test runner begins executing all the tests but afterwards just goes blank. See image below.

My Karma Config:

module.exports = function (config) {
  config.set({
    basePath: '',
    frameworks: ['jasmine', '@angular/cli'],
    plugins: [
      require('karma-jasmine'),
      require('karma-chrome-launcher'),
      require('karma-jasmine-html-reporter'),
      require('karma-coverage-istanbul-reporter'),
      require('@angular/cli/plugins/karma')
    ],
    client:{
      clearContext: false // leave Jasmine Spec Runner output visible in browser
    },
    files: [
      { pattern: './src/test.ts', watched: false }
    ],
    preprocessors: {
      './src/test.ts': ['@angular/cli']
    },
    mime: {
      'text/x-typescript': ['ts','tsx']
    },
    coverageIstanbulReporter: {
      reports: [ 'html', 'lcovonly' ],
      fixWebpackSourcePaths: true
    },
    angularCli: {
      environment: 'dev'
    },
    reporters: config.angularCli && config.angularCli.codeCoverage
              ? ['progress', 'coverage-istanbul']
              : ['progress', 'kjhtml'],
    port: 9876,
    colors: true,
    logLevel: config.LOG_INFO,
    autoWatch: true,
    browsers: ['Chrome'],
    singleRun: false
  });
};

my Package.json devDeps:

"devDependencies": {
"@angular/cli": "1.0.3",
"@angular/compiler-cli": "^4.0.0",
"@types/jasmine": "2.5.38",
"@types/node": "~6.0.60",
"codelyzer": "~2.0.0",
"jasmine-core": "~2.5.2",
"jasmine-spec-reporter": "~3.2.0",
"karma": "~1.4.1",
"karma-chrome-launcher": "~2.1.1",
"karma-cli": "~1.0.1",
"karma-jasmine": "~1.1.0",
"karma-jasmine-html-reporter": "^0.2.2",
"karma-coverage-istanbul-reporter": "^0.2.0",
"protractor": "~5.1.0",
"ts-node": "~2.0.0",
"tslint": "~4.5.0",
"typescript": "~2.2.0"

}

Could it be a version issue? Maybe upgrade my Karma version? This was installed via cli, and I believe it was working earlier but somehow it has come to this.

Answer 1

The culprit is the client.clearContext option in the Karma configuration :

If true, Karma clears the context window upon the completion of running the tests. If false, Karma does not clear the context window upon the completion of running the tests. Setting this to false is useful when embedding a Jasmine Spec Runner Template.

To avoid blanking the screen, disable this option, like so (karma.conf.js):

module.exports = function (config) {
    config.set({
        /* ... */
        client: {
            clearContext: false
        }
        /* ... */
    })
}

Answer 2

It's because of npm version dependencies:-

 npm i --save-dev jasmine-core@latest
 npm i --save karma-jasmine@latest

Install these two dependencies this will resolve your issue.

Complete Package.json [FYR]

{
  "name": "karma-coverage-sample",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "karma start karma.conf.js"
  },
  "keywords": [],
  "author": "",
  "license": "ISC",
  "devDependencies": {
    "istanbul": "^0.4.5",
    "jasmine-core": "^3.5.0",
    "karma": "^1.3.0",
    "karma-chrome-launcher": "^2.0.0",
    "karma-coverage": "^1.1.1",
    "karma-jasmine": "^2.0.1",
    "karma-jasmine-html-reporter": "^1.5.1"
  }
}