title: Clarification on grunt-protractor-coverage syntax for rails app backend?
body: <h1>Background</h1>
  
  <p>I'm trying to use the grunt-protractor-coverage in my grunt script to get code coverage for  protractor functional e2e tests. To get started, I utilized <a href="http://java.dzone.com/articles/measuring-code-coverage" rel="nofollow">this tutorial</a>, with some minor modifications and it works perfectly. Using this as a guide, I created a new gruntfile, substituting the "express" app with a rails app backend. </p>
  
  <h2>The Problem</h2>
  
  <p>When running my gruntfile, I get the following stack trace:</p>
  
  <pre><code>../dummy/node_modules/grunt-protractor-coverage/node_modules/protractor/node_modules/glob/glob.js:130
  throw new Error("must provide pattern")
        ^
  Error: must provide pattern
      at new Glob (../dummy/node_modules/grunt-protractor-coverage/node_modules/protractor/node_modules/glob/glob.js:130:11)
      at glob ../dummy/node_modules/grunt-protractor-coverage/node_modules/protractor/node_modules/glob/glob.js:57:11)
      at Function.globSync [as sync] (../dummy/node_modules/grunt-protractor-coverage/node_modules/protractor/node_modules/glob/glob.js:76:10)
      at Function.ConfigParser.resolveFilePatterns (../dummy/node_modules/grunt-protractor-coverage/node_modules/protractor/lib/configParser.js:89:26)
      at Runner.run (../dummy/node_modules/grunt-protractor-coverage/node_modules/protractor/lib/runner.js:323:24)
      at process.&lt;anonymous&gt; (../dummy/node_modules/grunt-protractor-coverage/node_modules/protractor/lib/runFromLauncher.js:32:14)
      at process.EventEmitter.emit (events.js:98:17)
      at handleMessage (child_process.js:318:10)
      at Pipe.channel.onread (child_process.js:345:11)
  [launcher] Runner Process Exited With Error Code: 8
  </code></pre>
  
  <p>Tracing through the code in grunt's task.js file via [node-inspector] (<a href="https://github.com/node-inspector/node-inspector" rel="nofollow">https://github.com/node-inspector/node-inspector</a>), it seems there are two possible issues:</p>
  
  <ol>
  <li>I'm missing some parameter from my config file which would correctly retrieve the files needed</li>
  <li>There is a syntax issue</li>
  </ol>
  
  <p><strong>Any idea why it's throwing this error?</strong></p>
  
  <h2>My Config File</h2>
  
  <pre><code>protractor_coverage: {
      options: {
          configFile: '/usr/local/lib/node_modules/protractor/referenceConf.js', // Default config file
          keepAlive: true, // If false, the grunt process stops when the test fails.
          noColor: false, // If true, protractor will not use colors in its output.
          coverageDir: '&lt;%= dirs.instrumentedE2E %&gt;',
          args: {}
      },
      phantom: {
          options: {
              args: {
                  baseUrl: 'http://localhost:3000/',
                  // Arguments passed to the command
                  'browser': 'phantomjs'
              }
          }
      },
      chrome: {
          options: {
              args: {
                  baseUrl: 'http://localhost:3000/',
                  // Arguments passed to the command
                  'browser': 'chrome'
              }
          }
      }
  },
  </code></pre>