Enable testing with Python 3.11 (#9511)

.github/workflows/main.yml

@@ -37,6 +37,7 @@ jobs:
           "windows-py38",
           "windows-py39",
           "windows-py310",
+          "windows-py311",
 
           "ubuntu-py37",
           "ubuntu-py37-pluggy",
@@ -44,6 +45,7 @@ jobs:
           "ubuntu-py38",
           "ubuntu-py39",
           "ubuntu-py310",
+          "ubuntu-py311",
           "ubuntu-pypy3",
 
           "macos-py37",
@@ -78,6 +80,10 @@ jobs:
             python: "3.10"
             os: windows-latest
             tox_env: "py310-xdist"
+          - name: "windows-py311"
+            python: "3.11-dev"
+            os: windows-latest
+            tox_env: "py311"
 
           - name: "ubuntu-py37"
             python: "3.7"
@@ -104,6 +110,10 @@ jobs:
             python: "3.10"
             os: ubuntu-latest
             tox_env: "py310-xdist"
+          - name: "ubuntu-py311"
+            python: "3.11-dev"
+            os: ubuntu-latest
+            tox_env: "py311"
           - name: "ubuntu-pypy3"
             python: "pypy-3.7"
             os: ubuntu-latest

testing/test_assertion.py

@@ -1026,7 +1026,7 @@ class TestAssert_reprcompare_attrsclass:
         assert lines is None
 
     def test_attrs_with_custom_eq(self) -> None:
-        @attr.define
+        @attr.define(slots=False)
         class SimpleDataObject:
             field_a = attr.ib()
 
@@ -1648,7 +1648,7 @@ def test_raise_unprintable_assertion_error(pytester: Pytester) -> None:
     )
 
 
-def test_raise_assertion_error_raisin_repr(pytester: Pytester) -> None:
+def test_raise_assertion_error_raising_repr(pytester: Pytester) -> None:
     pytester.makepyfile(
         """
         class RaisingRepr(object):
@@ -1659,9 +1659,15 @@ def test_raise_assertion_error_raisin_repr(pytester: Pytester) -> None:
     """
     )
     result = pytester.runpytest()
-    result.stdout.fnmatch_lines(
+    if sys.version_info >= (3, 11):
-        ["E       AssertionError: <unprintable AssertionError object>"]
+        # python 3.11 has native support for un-str-able exceptions
-    )
+        result.stdout.fnmatch_lines(
+            ["E       AssertionError: <exception str() failed>"]
+        )
+    else:
+        result.stdout.fnmatch_lines(
+            ["E       AssertionError: <unprintable AssertionError object>"]
+        )
 
 
 def test_issue_1944(pytester: Pytester) -> None:

testing/test_compat.py

@@ -1,4 +1,5 @@
 import enum
+import sys
 from functools import partial
 from functools import wraps
 from typing import TYPE_CHECKING
@@ -91,6 +92,7 @@ def test_get_real_func_partial() -> None:
     assert get_real_func(partial(foo)) is foo
 
 
+@pytest.mark.skipif(sys.version_info >= (3, 11), reason="couroutine removed")
 def test_is_generator_asyncio(pytester: Pytester) -> None:
     pytester.makepyfile(
         """

testing/test_doctest.py

@@ -1,4 +1,5 @@
 import inspect
+import sys
 import textwrap
 from pathlib import Path
 from typing import Callable
@@ -200,6 +201,7 @@ class TestDoctests:
                 "Traceback (most recent call last):",
                 '  File "*/doctest.py", line *, in __run',
                 "    *",
+                *((" *^^^^*",) if sys.version_info >= (3, 11) else ()),
                 '  File "<doctest test_doctest_unexpected_exception.txt[1]>", line 1, in <module>',
                 "ZeroDivisionError: division by zero",
                 "*/test_doctest_unexpected_exception.txt:2: UnexpectedException",

testing/test_main.py

@@ -1,6 +1,7 @@
 import argparse
 import os
 import re
+import sys
 from pathlib import Path
 from typing import Optional
 
@@ -44,16 +45,32 @@ def test_wrap_session_notify_exception(ret_exc, pytester: Pytester) -> None:
         assert result.ret == ExitCode.INTERNAL_ERROR
     assert result.stdout.lines[0] == "INTERNALERROR> Traceback (most recent call last):"
 
+    end_lines = (
+        result.stdout.lines[-4:]
+        if sys.version_info >= (3, 11)
+        else result.stdout.lines[-3:]
+    )
+
     if exc == SystemExit:
-        assert result.stdout.lines[-3:] == [
+        assert end_lines == [
             f'INTERNALERROR>   File "{c1}", line 4, in pytest_sessionstart',
             'INTERNALERROR>     raise SystemExit("boom")',
+            *(
+                ("INTERNALERROR>     ^^^^^^^^^^^^^^^^^^^^^^^^",)
+                if sys.version_info >= (3, 11)
+                else ()
+            ),
             "INTERNALERROR> SystemExit: boom",
         ]
     else:
-        assert result.stdout.lines[-3:] == [
+        assert end_lines == [
             f'INTERNALERROR>   File "{c1}", line 4, in pytest_sessionstart',
             'INTERNALERROR>     raise ValueError("boom")',
+            *(
+                ("INTERNALERROR>     ^^^^^^^^^^^^^^^^^^^^^^^^",)
+                if sys.version_info >= (3, 11)
+                else ()
+            ),
             "INTERNALERROR> ValueError: boom",
         ]
     if returncode is False:

testing/test_pytester.py

@@ -743,8 +743,8 @@ def test_run_result_repr() -> None:
 
     # known exit code
     r = pytester_mod.RunResult(1, outlines, errlines, duration=0.5)
-    assert (
+    assert repr(r) == (
-        repr(r) == "<RunResult ret=ExitCode.TESTS_FAILED len(stdout.lines)=3"
+        f"<RunResult ret={str(pytest.ExitCode.TESTS_FAILED)} len(stdout.lines)=3"
         " len(stderr.lines)=4 duration=0.50s>"
     )
 

tox.ini

@@ -8,6 +8,7 @@ envlist =
     py38
     py39
     py310
+    py311
     pypy3
     py37-{pexpect,xdist,unittestextras,numpy,pluggymain}
     doctesting