Try manual install of nox

.github/workflows/test.yml

@@ -1,22 +1,51 @@
 name: Run tests
 
 on:
-  push:
-    branches: [ master ]
   pull_request:
-    branches: [ master ]
+    paths:
+      - '.github/workflows/test.yml'
+      - '**.py'
+  push:
+    paths:
+      - '.github/workflows/test.yml'
+      - '**.py'
 
 jobs:
-  build:
-    runs-on: ubuntu-latest
+  test:
+    runs-on: ${{ matrix.os }}-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [ubuntu]
+        python_version: ['3.6', '3.7', '3.8']
+
     steps:
-      - uses: actions/checkout@1.0.0
-      - uses: excitedleigh/setup-nox@0.1.0
-      - name: Run tests
-        run: nox
-      - name: Submit coverage results
-        env:
-          COVERALLS_REPO_TOKEN: ${{ secrets.COVERALLS_REPO_TOKEN }}
-        run: |
-          pip install coveralls
-          coveralls
+    - uses: actions/checkout@v1
+
+    - uses: actions/setup-python@v1
+      name: Install Python ${{ matrix.python_version }}
+      with:
+        python-version: ${{ matrix.python_version }}
+
+    - uses: actions/setup-python@v1
+      name: Install Python 3.x
+      with:
+        python-version: 3.x
+
+    - name: Install dependencies
+      run: |
+        python -m pip install --upgrade pip
+        python -m pip install nox
+      shell: bash
+
+    - name: Run tests
+      run: |
+        python -m nox -s test-${{ matrix.python_version }}
+      shell: bash
+
+    - name: Submit coverage results
+      env:
+        COVERALLS_REPO_TOKEN: ${{ secrets.COVERALLS_REPO_TOKEN }}
+      run: |
+        pip install coveralls
+        coveralls