Use toxenv instead

Author: jamesls

.travis.yml

@@ -7,9 +7,9 @@ env:
 sudo: false
 install:
   - travis_retry pip install tox
-  - if [[ $TRAVIS_PYTHON_VERSION == '2.7' ]]; then pip install -r requirements-dev.txt; fi
+  - if [[ $TOXENV == 'py27' ]]; then pip install -r requirements-dev.txt; pip install -e .; fi
 script:
   - tox
   # We only need to run the lint/flake8 checks on one version of python
   # So I've arbitrarily chosen python2.7.
-  - if [[ $TRAVIS_PYTHON_VERSION == '2.7' ]]; then make check; fi
+  - if [[ $TOXENV == 'py27' ]]; then make check; fi