Use tox to run the test suite in CI for isolation

Signed-off-by: Bernat Gabor <bgabor8@bloomberg.net>

.github/workflows/check.yml

@@ -25,16 +25,26 @@ jobs:
         - pypy3
         - pypy2
     steps:
+    - name: Setup graphviz
+      uses: ts-graphviz/setup-graphviz@v1
+    - name: Setup python for tox
+      uses: actions/setup-python@v2
+      with:
+        python-version: 3.8
+    - name: Install tox
+      run: python -m pip install tox
     - name: Setup python for test ${{ matrix.py }}
       uses: actions/setup-python@v2
       with:
         python-version: ${{ matrix.py }}
     - uses: actions/checkout@v2
-    - name: Setup graphviz
-      uses: ts-graphviz/setup-graphviz@v1
-    - name: Install dev requirements
-      run: pip install -r dev-requirements.txt
-    - name: Install project
-      run: pip install .[graphviz]
+    - name: Pick tox environment to run
+      run: |
+        import subprocess; import json
+        major, minor, impl = json.loads(subprocess.check_output(["python", "-c", "import json; import sys; import platform; print(json.dumps([sys.version_info[0], sys.version_info[1], platform.python_implementation()]));"], universal_newlines=True))
+        print('::set-env name=TOXENV::' + ("py" if impl == "CPython" else "pypy") + ("{}{}".format(major, minor) if impl == "CPython" else ("3" if major == 3 else "")))
+      shell: python
+    - name: Setup test suite
+      run: tox -vv --notest
     - name: Run test suite
-      run: pytest -v tests
+      run: tox --skip-pkg-install

dev-requirements.txt

@@ -1,8 +0,0 @@
-flake8
-graphviz
-pip>=8.0.2
-pytest
-pytest-cov
-tox>=3
-virtualenv>=20,<21
-mock;python_version<"3"

tox.ini

@@ -22,3 +22,5 @@ deps =
   pytest-cov
   virtualenv>=20,<21
   mock;python_version<"3"
+extras =
+  graphviz