language: python
python: 2.7
env:
  - TOX_ENV=py27
  - TOX_ENV=flake8
install:
  - pip install tox
script:
  - tox -e $TOX_ENV

language: python
python: 2.7
env:
  - TOX_ENV=py27
  - TOX_ENV=flake8
install:
  - pip install tox
script:
  - tox -e $TOX_ENV
cache: pip

Add pip caching to Travis config
Add pip caching to Travis config

As the title says.
