Add a test workflow for github actions

.github/workflows/tests.yml

@@ -0,0 +1,31 @@
+name: Python tests
+
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: [ master ]
+
+jobs:
+  test:
+    name: Run tests on ${{ matrix.os }} with Python ${{ matrix.python }}
+    strategy:
+      matrix:
+        os: [ubuntu-latest, macOS-latest]
+        python: ['3.8', '3.7']
+    runs-on: ${{ matrix.os }}
+
+    steps:
+    - uses: actions/checkout@v2
+    - name: Set up Python ${{ matrix.python }}
+      uses: actions/setup-python@v1
+      with:
+        python-version: ${{ matrix.python }}
+    - name: Install dependencies
+      run: |
+        python -m pip install --upgrade pip
+        pip install pytest
+        if [ -f requirements.txt ]; then pip install -r requirements.txt; fi
+    - name: Run tests
+      run: |
+        pytest