Create separate environment

Author: rhpvorderman

.travis.yml

@@ -11,7 +11,8 @@ before_install:
   - conda config --add channels defaults
   - conda config --add channels conda-forge
 install:
-  - conda install python=$TRAVIS_PYTHON_VERSION isa-l tox
+  - conda create -n test python=$TRAVIS_PYTHON_VERSION isa-l tox
+  - source activate test
 
 python: 3.5  # Use the oldest supported version of python as default.
 script: