language: python
python:
  - "2.6"
  - "2.7"
  - "3.3"
  - "3.4"
  - "pypy"
env:
  - INSTALL_PYMONGO=true INSTALL_PYEXECJS=true
  - INSTALL_PYMONGO=false INSTALL_PYEXECJS=false
services:
  - mongodb
# command to install dependencies, e.g. pip install -r requirements.txt
install: 
  - python setup.py develop
  - travis_retry pip install nose
# command to run tests, e.g. python setup.py test
script: nosetests -w tests

language: python
python:
  - "2.6"
  - "2.7"
  - "3.3"
  - "3.4"
  - "pypy"
env:
  - INSTALL_PYMONGO=true INSTALL_PYEXECJS=true
  - INSTALL_PYMONGO=false INSTALL_PYEXECJS=false
services:
  - mongodb
# command to install dependencies, e.g. pip install -r requirements.txt
install: 
  - travis_retry pip install -e .
  - travis_retry pip install nose
# command to run tests, e.g. python setup.py test
script: nosetests -w tests

Use pip to install dependencies so you'd be able to retry failed installations.
Use pip to install dependencies so you'd be able to retry failed installations.