I installed the following for testing:
"devDependencies": {
    "jasmine-core": "^2.4.1",
    "karma": "^0.13.22",
    "karma-jasmine": "^0.3.7",
    "karma-phantomjs-launcher": "^1.0.0"
}
After running karma start I get the following error:
Doing a search this is the first question with the same problem: karma start Cannot find module 'jasmine-core'
However I've tried both answers, installed jasmine-core globally and I already did npm install jasmine-core --save-dev :(
My test/index.html
<!DOCTYPE html>
<html lang="en">
<head>
    <title>Jasmine Spec Runner</title>
    <link href="testing.css" rel="stylesheet">
    <script src="../app/assets/js/libs/vendors.min.js"></script>
    <script src="../app/assets/js/bundle.js"></script>
</head>
<body>
    <div>
        <header>
            <h1>Jasmine tests for Dashboard</h1>
        </header>
    </div>
</body>
</html>
My karma.conf.js
// Karma configuration
// Generated on Mon Mar 14 2016 11:56:04 GMT-0500 (CDT)
module.exports = function(config) {
  config.set({
    // base path that will be used to resolve all patterns (eg. files, exclude)
    basePath: '.',
    // frameworks to use
    // available frameworks: https://npmjs.org/browse/keyword/karma-adapter
    frameworks: ['jasmine'],
    // list of files / patterns to load in the browser
    files: [
      'app/assets/js/bundle.js',
      'test/**/*.js'
    ],
    // list of files to exclude
    exclude: [
    ],
    // preprocess matching files before serving them to the browser
    // available preprocessors: https://npmjs.org/browse/keyword/karma-preprocessor
    preprocessors: {
    },
    // test results reporter to use
    // possible values: 'dots', 'progress'
    // available reporters: https://npmjs.org/browse/keyword/karma-reporter
    reporters: ['progress'],
    // web server port
    port: 9876,
    // enable / disable colors in the output (reporters and logs)
    colors: true,
    // level of logging
    // possible values: config.LOG_DISABLE || config.LOG_ERROR || config.LOG_WARN || config.LOG_INFO || config.LOG_DEBUG
    logLevel: config.LOG_INFO,
    // enable / disable watching file and executing tests whenever any file changes
    autoWatch: false,
    // start these browsers
    // available browser launchers: https://npmjs.org/browse/keyword/karma-launcher
    browsers: ['PhantomJS'],
    // Continuous Integration mode
    // if true, Karma captures browsers, runs the tests and exits
    singleRun: true,
    // Concurrency level
    // how many browser should be started simultaneous
    concurrency: Infinity
  })
}

 
     
     
     
     
     
    