Run against 3.12-dev in CI (#14050)

.github/workflows/test.yml

@@ -137,3 +137,21 @@ jobs:
       run: tox -e ${{ matrix.toxenv }} --notest
     - name: Test
       run: tox -e ${{ matrix.toxenv }} --skip-pkg-install -- ${{ matrix.tox_extra_args }}
+
+  python-nightly:
+    runs-on: ubuntu-latest
+    name: Test suite with Python nightly
+    steps:
+      - uses: actions/checkout@v3
+      - uses: actions/setup-python@v4
+        with:
+          python-version: '3.12-dev'
+      - name: Install tox
+        run: pip install --upgrade 'setuptools!=50' tox==3.24.5
+      - name: Setup tox environment
+        run: tox -e py --notest
+      - name: Test
+        run: tox -e py --skip-pkg-install -- "-n 2"
+        continue-on-error: true
+      - name: Mark as a success
+        run: exit 0

mypyc/test/test_run.py

@@ -312,6 +312,9 @@ def run_case_step(self, testcase: DataDrivenTestCase, incremental_step: int) ->
             stderr=subprocess.STDOUT,
             env=env,
         )
+        if sys.version_info >= (3, 12):
+            # TODO: testDecorators1 hangs on 3.12, remove this once fixed
+            proc.wait(timeout=30)
         output = proc.communicate()[0].decode("utf8")
         outlines = output.splitlines()
 

test-requirements.txt

@@ -7,7 +7,7 @@ flake8==5.0.4           # must match version in .pre-commit-config.yaml
 flake8-bugbear==22.9.23 # must match version in .pre-commit-config.yaml
 flake8-noqa==1.2.9      # must match version in .pre-commit-config.yaml
 isort[colors]==5.10.1   # must match version in .pre-commit-config.yaml
-lxml>=4.9.1; python_version<'3.11' or sys_platform!='win32'
+lxml>=4.9.1; (python_version<'3.11' or sys_platform!='win32') and python_version<'3.12'
 psutil>=4.0
 # pytest 6.2.3 does not support Python 3.10
 pytest>=6.2.4