Testing: Add macOS worker in Travis

.travis.yml

@@ -5,7 +5,11 @@ dist: trusty
 sudo: false
 
 matrix:
+  fast_finish: true
   include:
+    - python: "3.6"
+      env: USE_PYQT=pyqt5 USE_CONDA=yes
+      os: osx
     - python: "2.7"
       env: USE_PYQT=pyqt5 USE_CONDA=yes
       os: linux
@@ -20,18 +24,18 @@ matrix:
       os: linux
 
 before_install:
-  - "export DISPLAY=:99.0"
-  - "sh -e /etc/init.d/xvfb start"
+  - if [[ "$TRAVIS_OS_NAME" == "linux" ]]; then export DISPLAY=:99.0; fi
+  - if [[ "$TRAVIS_OS_NAME" == "linux" ]]; then sh -e /etc/init.d/xvfb start; fi
   # Avoid annoying focus problems when running tests
   # See discussion in e.g. https://github.com/spyder-ide/spyder/pull/6132
-  - sudo apt-get -qq update
-  - sudo apt-get install -y matchbox-window-manager
+  - if [[ "$TRAVIS_OS_NAME" == "linux" ]]; then sudo apt-get -qq update; fi
+  - if [[ "$TRAVIS_OS_NAME" == "linux" ]]; then sudo apt-get install -y matchbox-window-manager; fi
 
 install:
   - ./continuous_integration/travis/install.sh;
   - ./continuous_integration/travis/install-qt.sh;
-  - DISPLAY=:99 matchbox-window-manager &
-  - sleep 5
+  - if [[ "$TRAVIS_OS_NAME" == "linux" ]]; then DISPLAY=:99 matchbox-window-manager& fi
+  - if [[ "$TRAVIS_OS_NAME" == "linux" ]]; then sleep 5; fi
 
 script:
   - ./continuous_integration/travis/runtests.sh || ./continuous_integration/travis/runtests.sh || ./continuous_integration/travis/runtests.sh;