ci/cirrus: remove tox

.cirrus.yml

@@ -16,12 +16,14 @@ test_task:
     - pkg install -y git-lite curl $PYPACKAGE $SQLPACKAGE
   pip_script:
     - $PYTHON -m ensurepip
-    - $PYTHON -m pip --disable-pip-version-check install -U pip tox virtualenv
+    - $PYTHON -m pip --disable-pip-version-check install -U pip
   poetry_script:
     - curl -sL https://raw.githubusercontent.com/python-poetry/poetry/master/install-poetry.py \
       | $PYTHON - -y
     - poetry config virtualenvs.in-project true
-  tox_script: $PYTHON -m tox -e py -- -q --junitxml=junit.xml tests
+  test_script: |
+    poetry install
+    poetry run pytest -q --junitxml=junit.xml tests
   on_failure:
     annotate_failure_artifacts:
       path: junit.xml