title: Grunt Karma unit task fail with AngularJS project
body: <p>I have a problem executing <strong>grunt karma:unit</strong>, the task finished but throw this:</p>
  
  <pre><code>.......
  DEBUG [web-server]: serving (cached): C:/project/yo
  /test/spec/services/lists.js
  Firefox 32.0.0 (Windows 7): Executed 0 of 0 ERROR (0.027 secs / 0 secs)
  DEBUG [karma]: Run complete, exiting.
  DEBUG [launcher]: Disconnecting all browsers
  DEBUG [launcher]: Process Firefox exited with code 0
  DEBUG [temp-dir]: Cleaning temp dir C:\Users\developer\AppData\Local\Temp\karma-14
  854612
  Warning: Task "karma:unit" failed. Use --force to continue.
  
  Aborted due to warnings.
  
  
  Execution Time (2014-10-16 21:25:51 UTC)
  karma:unit  4.1s  ■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■ 100%
  Total 4.1s
  </code></pre>
  
  <p>The test directory contains the test empty, for example: </p>
  
  <pre><code>'use strict';
  
  describe('Service: lists', function () {
  
  });
  </code></pre>
  
  <p>I don't understand why the result is: <strong>Warning: Task "karma:unit" failed. Use --force to continue.</strong>.</p>
  
  <p>My karma.conf.js file contains:</p>
  
  <pre><code>module.exports = function(config) {
    'use strict';
  
    config.set({
      autoWatch: true,
  
      basePath: '../',
  
      // testing framework to use (jasmine/mocha/qunit/...)
      frameworks: ['jasmine'],
  
      // list of files / patterns to load in the browser
      files: [
        'app/bower_components/jquery/dist/jquery.js',
        'app/bower_components/angular/angular.js',
        'app/bower_components/json3/lib/json3.js',
        'app/bower_components/bootstrap/dist/js/bootstrap.js',
        'app/bower_components/jquery-ui/jquery-ui.js',     
        'app/bower_components/angular-animate/angular-animate.js',
        'app/bower_components/angular-route/angular-route.js',
        'app/bower_components/angular-sanitize/angular-sanitize.js',
        'app/bower_components/angular-touch/angular-touch.js',      
        'app/bower_components/lodash/dist/lodash.compat.js',      
        'app/bower_components/restangular/dist/restangular.js',
        'app/bower_components/angular-ui-router/release/angular-ui-router.js',
        'app/bower_components/angular-bootstrap/ui-bootstrap-tpls.js',
        'app/bower_components/angular-translate/angular-translate.js',
        'app/bower_components/angular-moment/angular-moment.js',
        'app/bower_components/angular-ui-router/release/angular-ui-router.js',
        'app/bower_components/angular-translate-loader-static-files/angular-translate-loader-static-files.js',      
        'app/scripts/**/*.js',
        'test/spec/**/*.js'
      ],
  
      exclude: [],
  
      port: 8080,
  
      browsers: [
        'Firefox'
      ],
  
      plugins: [
        'karma-firefox-launcher',
        'karma-jasmine'
      ],
  
      singleRun: false,
  
      colors: true,
  
      logLevel: config.LOG_DEBUG,
    });
  };
  </code></pre>