Merge pull request #245 from thewtex/ci-macos

ENH: GitHub Actions testing for macOS

.github/workflows/build-test.yml

@@ -5,10 +5,11 @@ on: [push,pull_request]
 jobs:
   build:
 
-    runs-on: ubuntu-latest
+    runs-on: ${{ matrix.os }}
     strategy:
       max-parallel: 4
       matrix:
+        os: [ubuntu-latest, macos-latest]
         python-version: [3.5, 3.6, 3.7]
 
     steps:
@@ -21,7 +22,7 @@ jobs:
       run: |
         python -m pip install --upgrade pip
         python -m pip install --upgrade setuptools wheel
-        pip install -r requirements.txt -r requirements-dev.txt
+        pip install -r requirements.txt -r requirements-dev.txt PySide2
     - name: Install package and extension
       run: |
         python -m pip install -e .
@@ -31,6 +32,8 @@ jobs:
         python -m pip install jupyterlab
         jupyter labextension install @jupyter-widgets/jupyterlab-manager
         jupyter labextension install ./js
+      env:
+        MPLBACKEND: Qt5Agg
     - name: Lint with flake8
       run: |
         python -m pip install flake8
@@ -42,6 +45,8 @@ jobs:
       run: |
         python -m pip install pytest
         python -m pytest --tb=long --verbose --deselect tests/test_transform_types.py::test_vtkpolydata_to_geometry
+      env:
+        MPLBACKEND: Qt5Agg
     - name: Test package generation and installation
       run: |
         python setup.py sdist