Karma Istanbul and Browserify

gulpfile.js

var gulp = require('gulp');
var browserify = require('browserify')
var source = require('vinyl-source-stream');
var istanbulTransform = require('browserify-istanbul');
var karmaServer = require('karma').server;
var glob = require('glob');

gulp.task('coverage',['build-instrument'] , function(done) {
    karmaServer.start({
      configFile: __dirname + '/karma.conf.js',
      singleRun: true
    }, done)
  });
  //instruments the code to be 
  gulp.task('build-instrument', function() {
    var files = glob.sync('./public/js/**.js');
   
    return browserify({
      debug: env =='development'
    })
    .add(files)
    .transform(istanbulTransform({
      ignore: ['**/node_modules/**', '**/test/**', '**/tests/**','**/**.handlebars'],
    }))
    .bundle()
    .pipe(source('instrument.js'))
    .pipe(gulp.dest('.'))
  });

karma.conf.js

var istanbul = require('browserify-istanbul');
// Karma configuration
// Generated on Fri Nov 21 2014 13:33:54 GMT-0500 (EST)

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
    // note the browserify framework is required
    frameworks: ['browserify','mocha', 'chai'],


    // list of files / patterns to load in the browser
    files: [
      'tests/js/**/**.js',
      // the instrumented code from istanbul
      './instrument.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: {
      'tests/js/**': ['sourcemap','browserify'],
      './instrument.js': ['sourcemap']
       
    },

    browserify: {
      transform: [],
      debug: true,

      // don't forget to register the extensions
      extensions: ['.js', '.jsx', '.coffee']
    },
    // test results reporter to use
    // possible values: 'dots', 'progress'
    // available reporters: https://npmjs.org/browse/keyword/karma-reporter
    // here the coverage reporter would be running to output the final coverage report
    reporters: ['coverage'],


    // 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,

    browserNoActivityTimeout: 20000,
    // start these browsers
    // available browser launchers: https://npmjs.org/browse/keyword/karma-launcher
    browsers: ['PhantomJS'],
    coverageReporter: {
    reporters:[
        {type: 'html', dir:'coverage/'},
        {type: 'text'},
        {type: 'text-summary'}
      ],
    },

    // Continuous Integration mode
    // if true, Karma captures browsers, runs the tests and exits
    singleRun: false
  });
};