Ignore sprurious cython import warning under pypy

See yaml/pyyaml#688 (and possibly cython/cython#1720), doesn't look
like there's really a better way to fix it than ignore the issue, but
that's simple enough, as it's just an additional `-W` flag on the
pytest invocation.

While at it, add pypy-3.9 and convert versions array to a yaml list for
better readability and diff-ability.

.github/workflows/ci.yml

@@ -32,7 +32,17 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: ["2.7", "3.6", "3.7", "3.8", "3.9", "3.10", "3.11", "3.12.0-alpha - 3.12", "pypy-3.8"]
+        python-version:
+          - "2.7"
+          - "3.6"
+          - "3.7"
+          - "3.8"
+          - "3.9"
+          - "3.10"
+          - "3.11"
+          - "3.12.0-alpha - 3.12"
+          - "pypy-3.8"
+          - "pypy-3.9"
         pyyaml-version: ["5.1.*", "5.4.*", "6.0.*", "6.*"]
         include:
           - python-version: 3.6
@@ -66,7 +76,17 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: ["2.7", "3.6", "3.7", "3.8", "3.9", "3.10", "3.11", "3.12.0-alpha - 3.12", "pypy-3.8"]
+        python-version:
+          - "2.7"
+          - "3.6"
+          - "3.7"
+          - "3.8"
+          - "3.9"
+          - "3.10"
+          - "3.11"
+          - "3.12.0-alpha - 3.12"
+          - "pypy-3.8"
+          - "pypy-3.9"
         include:
           - python-version: 3.6
             os: ubuntu-20.04
@@ -84,7 +104,7 @@ jobs:
         python -mpip install --upgrade pip
         # if binary wheels are not available for the current package install libyaml
         # NB: cyaml is outright broken on pypy so exclude that
-        if ! ${{matrix.python-version == 'pypy-3.8'}}; then
+        if ! ${{ startsWith(matrix.python-version, 'pypy-') }}; then
             if ! pip download --only-binary pyyaml -rrequirements_dev.txt > /dev/null 2>&1; then
                 sudo apt install libyaml-dev
             fi
@@ -93,7 +113,8 @@ jobs:
     - name: install package in environment
       run: python setup.py develop
     - name: run tests
-      run: pytest -v -Werror
+      # 
+      run: pytest -v -Werror -Wignore::ImportWarning
     - name: run doctests
       # pprint formatting was changed a lot in 3.5
       if: ${{ matrix.python-version != '2.7' }}

tox.ini

@@ -1,5 +1,7 @@
 [tox]
-envlist = py27, py36, py37, py38, py39, py310, pypy3.8, docs, flake8, black
+envlist = py27, py36, py37, py38, py39, py310, py311,
+          pypy3.8, pypy3.9,
+          docs, flake8, black
 skipsdist = True
 
 [testenv]