title: karma setup giving require is not defined
body: <p>I'm new at setting up karma and testing here, so I've been going through a bunch of examples out there to set my env up.
  However, whenever I run <code>karma start</code>, it gives me this:</p>
  
  <pre><code>Uncaught ReferenceError: require is not defined
  at test/person-test.js:1
  </code></pre>
  
  <p>I think I probably didn't set up my <code>karma.conf.js</code> correctly, does anyone have any clue? This is what I have:</p>
  
  <pre><code>module.exports = function(config) {
    config.set({
  
      basePath: '',
      frameworks: ['jasmine', 'browserify'],
      files: [
        'test/**/*.js'
      ],
      exclude: [],
      preprocessors: {
        'src/**/*.js': ['browserify']
      },
      plugins: [
        'karma-chrome-launcher',
        'karma-jasmine',
        'karma-browserify'
        ],
      browserify: {
        debug: true,
        transform: [ 'brfs', 'browserify-shim' ]
      },
      reporters: ['progress'],
      port: 9876,
      colors: true,
      logLevel: config.LOG_INFO,
      autoWatch: true,
      browsers: ['Chrome'],
      singleRun: false,
      concurrency: Infinity
    })
  }
  </code></pre>
  
  <p>I have file structure like this:</p>
  
  <pre><code>.
  ├── src
  |   └── person.js
  ├── test
  |   ├── person-test.js
  ├── karma.conf.js
  └── package.json
  </code></pre>
  
  <p>Where my <code>person.js</code> file is like this:</p>
  
  <pre><code>class Person {
    constructor(name, age) {
      this.name = name;
      this.age = age;
    }
  
    upperCaseName() {
      this.name = this.name.upperCaseName();
    }
  }
  
  module.exports = Person;
  </code></pre>
  
  <p>and (so far) my <code>person-test.js</code> is:</p>
  
  <pre><code>const Person = require('../src/person.js')
  </code></pre>