Move test formatting at the beginning of github action

.github/workflows/main.yml

@@ -17,19 +17,22 @@ jobs:
       uses: actions/setup-python@v1
       with:
         python-version: ${{ matrix.python-version }}
-    - name: Install dependencies
-      run: |
-        python -m pip install --upgrade pip
-        pip install -r requirements.txt
-    - name: Test with pytest
-      run: |
-        pip install pytest
-        pytest
+
     - name: Test formatting
       run: |
         pip install black
         black --check .
 
+    - name: Install dependencies
+      run: |
+        python -m pip install --upgrade pip
+        pip install -r requirements.txt
+
+    - name: Test with pytest
+      run: |
+        pip install pytest
+        pytest
+
     - name: Publish to Docker Registry
       uses: elgohr/Publish-Docker-Github-Action@master
       with: