title: Chrome runs tests twice in karma
body: <p>When using Chrome in my karma tests, I often (more than 50% of all runs) see that each test is executed twice by Chrome. Below you can find an example output and my configuration.</p>
  
  <p>How can I stop this? What is the cause?</p>
  
  <pre><code>karma start --single-run --browsers Firefox,Chrome
  
  INFO [karma]: Karma v0.12.17 server started at http://localhost:9876/
  INFO [launcher]: Starting browser Firefox
  INFO [launcher]: Starting browser Chrome
  
  INFO [Chrome 36.0.1985 (Linux)]: Connected on socket RV8G8p63bCLQGaAJW9Hc with id 91444447
  Chrome 36.0.1985 (Linux): Executed 0 of 92 SUCCESS (0 secs / 0 secs)
  Chrome 36.0.1985 (Linux): Executed 1 of 92 SUCCESS (0 secs / 0.065 secs)
  [...]
  Chrome 36.0.1985 (Linux): Executed 91 of 92 SUCCESS (0 secs / 0.24 secs)
  Chrome 36.0.1985 (Linux): Executed 92 of 92 SUCCESS (0 secs / 0.241 secs)
  Chrome 36.0.1985 (Linux): Executed 92 of 92 SUCCESS (0.274 secs / 0.241 secs)
  Chrome 36.0.1985 (Linux): Executed 93 of 92 SUCCESS (0.274 secs / 0.258 secs)
  [...]
  Chrome 36.0.1985 (Linux): Executed 183 of 92 SUCCESS (0.274 secs / 0.412 secs)
  Chrome 36.0.1985 (Linux): Executed 184 of 92 SUCCESS (0.274 secs / 0.413 secs)
  
  INFO [Iceweasel 30.0.0 (Linux)]: Connected on socket 4DISHs7012QeIwhEW9Hd with id 93232241
  
  Chrome 36.0.1985 (Linux): Executed 184 of 92 SUCCESS (0.274 secs / 0.413 secs)
  Iceweasel 30.0.0 (Linux): Executed 0 of 92 SUCCESS (0 secs / 0 secs)
  Chrome 36.0.1985 (Linux): Executed 184 of 92 SUCCESS (0.274 secs / 0.413 secs)
  Iceweasel 30.0.0 (Linux): Executed 1 of 92 SUCCESS (0 secs / 0.003 secs)
  [...]
  Iceweasel 30.0.0 (Linux): Executed 91 of 92 SUCCESS (0 secs / 0.201 secs)
  Chrome 36.0.1985 (Linux): Executed 184 of 92 SUCCESS (0.274 secs / 0.413 secs)
  Iceweasel 30.0.0 (Linux): Executed 92 of 92 SUCCESS (0 secs / 0.202 secs)
  Chrome 36.0.1985 (Linux): Executed 184 of 92 SUCCESS (0.274 secs / 0.413 secs)
  Iceweasel 30.0.0 (Linux): Executed 92 of 92 SUCCESS (0.303 secs / 0.202 secs)
  TOTAL: 276 SUCCESS
  </code></pre>
  
  <p>Configuration:</p>
  
  <pre><code>module.exports = function(config) {
    config.set({
  
      basePath : 'www',
  
      frameworks : [ 'jasmine' ],
  
      files : [ 'js/*' ],
  
      exclude : [ 'spec/lib/*.js' ],
  
      reporters : [ 'progress', 'junit', 'html', 'coverage' ],
  
      coverageReporter : {
        type : 'html',
        dir : 'coverage/'
      },
  
      preprocessors : {
        'js/*.js' : 'coverage',
      },
  
      junitReporter : {
        outputFile : 'test-results.xml'
      },
  
      colors : true,
  
      logLevel : config.LOG_INFO,
  
      autoWatch : true,
  
      browsers : [ 'Firefox', 'Chrome' ],
  
      captureTimeout : 20000,
  
      reportSlowerThan : 500,
  
      plugins : [ 'karma-jasmine', 'karma-coverage', 'karma-html-reporter', 'karma-chrome-launcher', 'karma-junit-reporter', 'karma-phantomjs-launcher', 'karma-firefox-launcher' ]
  
    });
  };
  </code></pre>