I am developing a python adapter to interact with a 3rd party website, without any json or xml api (http://www.class.noaa.gov/). I have a problem when Travis CI run multiple python tests (of the The Travis CI Build Matrix) concurrently. The project is on GitHub at ecolell/noaaclass and the .travis.yml file is: language: python python: - "2.6" - "2.7" - "3.2" - "3.3" install: - "make deploy" script: "make test-coverage-travis-ci" #nosetests after_success: - "make test-coveralls" Specifically, I have a problem when at least 2 python versions were running their unit tests at the same time, because they use the same account of a website. Is there any option to specify to The Build Matrix the execution of each python version in a secuential way? Or maybe, Is there a better way to do this?