title: Gulp: Task function must be specified at Gulp.set
body: <p>When I try to run gulp I get the title error. </p>
  
  <p>My gulpfile.js:</p>
  
  <pre class="lang-js prettyprint-override"><code>    var gulp = require('gulp'),
          connect = require('gulp-connect-php'),
          gulpPhpunit = require('gulp-phpunit');
  
      gulp.task('gulpPhpunit', function() {
        var options = {debug: false};
        gulp.src('phpunit.xml') 
      .pipe(phpunit('./vendor/bin/phpunit',options));
      });
  
      gulp.task("default", ["gulpPhpunit"]);
  </code></pre>
  
  <p>The error</p>
  
  <pre class="lang-js prettyprint-override"><code>    // error
      assert.js:42
        throw new errors.AssertionError({
        ^
  
      AssertionError [ERR_ASSERTION]: Task function must be specified
          at Gulp.set [as _setTask] (/var/www/html/wptest2/node_modules/undertaker/lib/set-task.js:10:3)
          at Gulp.task (/var/www/html/wptest2/node_modules/undertaker/lib/task.js:13:8)
          at Object.&lt;anonymous&gt; (/var/www/html/wptest2/gulpfile.js:26:6)
          at Module._compile (module.js:652:30)
          at Object.Module._extensions..js (module.js:663:10)
          at Module.load (module.js:565:32)
          at tryModuleLoad (module.js:505:12)
          at Function.Module._load (module.js:497:3)
          at Module.require (module.js:596:17)
          at require (internal/module.js:11:18)
  </code></pre>
  
  <p>"Task function must be specified", am I not pointing to gulpPhpunit correctly? The code was copied out of the docs (example 2).</p>