anchor.diff:  output plugin.
   
   This is the approach taken by the tests in the
  -https://github.com/elastic/packetbeat/tree/master/tests[`tests`] directory. The
  +https://github.com/elastic/beats/tree/master/packetbeat/tests/system[`tests/system`] directory. The
   tests are written in Python and executed using
   https://nose.readthedocs.org/en/latest/[nose]. Here is a simple example test
   from the MongoDB suite:
  
positive.code: ----------------------------------------------------------------------
  $ mkdir -p $GOPATH/src/github.com/elastic
  $ cd $GOPATH/src/github.com/elastic
  $ git clone https://github.com/elastic/packetbeat.git
  ----------------------------------------------------------------------
  
  Then you can compile it with:
  
  [source,shell]
  ----------------------------------------------------------------------
  $ cd packetbeat
  $ make
  ----------------------------------------------------------------------
  
  
negative.code: 
  We recommend the following work flow for contributing to Packetbeat:
  
  * Fork Beats in GitHub to your own account
  
  * In the `$GOPATH/src/github.com/elastic/beats` folder, add your fork
    as a new remote. For example (replace `tsg` with your GitHub account):
  
  [source,shell]
  ----------------------------------------------------------------------
  $ git remote add tsg git@github.com:tsg/beats.git
  ----------------------------------------------------------------------
  
  * Create a new branch for your work:
  