anchor.diff:  WORKDIR /code
   RUN node --version
   RUN npm --version
  +RUN python2.7 --version
  +RUN ln -sf /usr/bin/python2.7 /usr/bin/python
   
   # Ubuntu's python-pip throws exception with requests lib
   # see https://bugs.launchpad.net/ubuntu/+source/python-pip/+bug/1306991
  
positive.code: # RUN echo ls /code; ls /code
  # RUN cd /code; tox -r
  
  # TODO consolidate all apt-get; clean up after install
  RUN apt-get install -y xvfb
  
  ENTRYPOINT ["purkinje", "-c", "purkinje.yml"]
  
negative.code: RUN echo 'Running installation'
  WORKDIR /code
  
  ENV DEBIAN_FRONTEND noninteractive
  ENV NODE_DIR=node-v6.2.0-linux-x64
  ENV NODE_ARCHIVE=$NODE_DIR.tar.xz
  ENV PATH=/opt/node/bin:$PATH
  
  RUN apt-get -y update && apt-get install -y \
          firefox \
          gcc \
          libyaml-dev \
          make \
          python2.7 \
          python2.7-dev \
          software-properties-common \
          wget \
          xvfb \
          xz-utils \
      && rm -rf /var/lib/apt/lists/*
  
  # Install Google Chrome
  RUN wget -q -O - https://dl-ssl.google.com/linux/linux_signing_key.pub | apt-key add -
  