Update workflow

Author: fabaff

.github/workflows/python-package.yml

@@ -20,10 +20,31 @@ jobs:
       uses: actions/setup-python@v2
       with:
         python-version: ${{ matrix.python-version }}
-    - name: Install dependencies
+
+    - name: Install Poetry
+      uses: dschep/install-poetry-action@v1.2
+
+    - name: Cache Poetry virtualenv
+      uses: actions/cache@v1
+      id: cache
+      with:
+        path: ~/.virtualenvs
+        key: poetry-${{ hashFiles('**/poetry.lock') }}
+        restore-keys: |
+          poetry-${{ hashFiles('**/poetry.lock') }}
+
+    - name: Set Poetry config
       run: |
-        python -m pip install --upgrade pip
-        pip install flake8 pytest
-        if [ -f requirements.txt ]; then pip install -r requirements.txt; fi
-    - name: Black Code Formatter
-      uses: lgeiger/black-action@v1.0.1
+        poetry config settings.virtualenvs.in-project false
+        poetry config settings.virtualenvs.path ~/.virtualenvs
+
+    - name: Install Dependencies
+      run: poetry install
+      if: steps.cache.outputs.cache-hit != 'true'
+
+    - name: Formatting
+      run: poetry run black . --check
+
+    - name: Test with pytest
+      run: poetry run pytest -n 2
+