travis now tests also on osx

.travis.yml

@@ -1,20 +1,40 @@
 
 language: python
-python:
-    - "2.7"
 
-virtualenv:
-    system_site_packages: true
+matrix:
+    include:
+        - os: linux
+          python: 2.7
+          env: TOXENV=py27
+        - os: osx
+          language: generic
+          env: TOXENV=py27
 
 before_install:
-    - travis_retry wget http://repo.continuum.io/miniconda/Miniconda-3.8.3-Linux-x86_64.sh -O miniconda.sh
+    # We do this conditionally because it saves us some downloading if the
+    # version is the same.
+    - if [[ "$TRAVIS_OS_NAME" == "linux" ]]; then
+        wget https://repo.continuum.io/miniconda/Miniconda-latest-Linux-x86_64.sh -O miniconda.sh;
+      else
+        brew update;
+        brew install python;
+        wget https://repo.continuum.io/miniconda/Miniconda2-latest-MacOSX-x86_64.sh -O miniconda.sh;
+      fi
     - chmod +x miniconda.sh
     - bash miniconda.sh -b -p $HOME/miniconda
-    - export PATH=/home/travis/miniconda/bin:$PATH
-    - conda update --yes conda
+    - export PATH="$HOME/miniconda/bin:$HOME/miniconda/lib:$PATH"
+    - hash -r
+    - conda config --set always_yes yes --set changeps1 no
+    - conda update -q conda
+    # Useful for debugging any issues with conda
+    - conda info -a
 
 install:
-    - conda create --yes -n test python=$TRAVIS_PYTHON_VERSION
+    - if [[ "$TRAVIS_OS_NAME" == "linux" ]]; then
+        conda create --yes -n test python=$TRAVIS_PYTHON_VERSION;
+      else
+        conda create --yes -n test python="2.7";
+      fi
     - source activate test
     - conda install --yes numpy scipy matplotlib pip nose vtk
     - conda install --yes -c https://conda.anaconda.org/dlr-sc pythonocc-core