Take 3.

.travis.yml

@@ -4,12 +4,9 @@ python:
   - "2.6"
   - "2.7"
   - "3.3"
-env:
-  - REQUIREMENTS=""
-  - REQUIREMENTS="unittest2"
 install:
-    - pip install $REQUIREMENTS
     - python setup.py -q install
 script:
+    - if [[ "$(python -c 'import sys; print sys.version_info[:2]')" == "(2, 6)" ]]; then pip install unittest2; fi
     - py.test --tb=native jsonschema
     - python -m doctest README.rst