Enable flake8-pytest-style (python-trio#2822)

* WIP enable flake8-pytest-style

* Update trio/_core/_tests/test_instrumentation.py

Co-authored-by: Sviatoslav Sydorenko <[email protected]>

* Apply suggestions from code review

Co-authored-by: Sviatoslav Sydorenko <[email protected]>

* Multiple parts of adding match argument

* Fix ruff issues

* Fix a few remaining windows match argument issues

* Add start and end tags to some of the match regexes

* Fix regexes

* Fix more regex errors

* Fix non-escaped `...`

* Fix unbalanced parenthesis

* Apply suggestions from code review

Co-authored-by: jakkdl <[email protected]>

* Fix `is` check

* Fix new changes from merging

* Add comments and simplify `test_socket.py`

* fix coverage fail - unrelated to this PR

* try coaxing CI to run

* pytest.raises(match=) makes assertion irrelevant

* revert test_highlevel_open_tcp_listeners fix, for another PR

---------

Co-authored-by: Sviatoslav Sydorenko <[email protected]>
Co-authored-by: jakkdl <[email protected]>
Co-authored-by: jakkdl <[email protected]>

pyproject.toml

@@ -103,6 +103,7 @@ select = [
   "PYI",  # flake8-pyi
   "SIM",  # flake8-simplify
   "TCH",  # flake8-type-checking
+  "PT",  # flake8-pytest-style
 ]
 extend-ignore = [
     'F403',  # undefined-local-with-import-star
@@ -131,6 +132,9 @@ extend-exclude = [
 [tool.ruff.isort]
 combine-as-imports = true
 
+[tool.ruff.flake8-pytest-style]
+fixture-parentheses = false
+
 [tool.mypy]
 python_version = "3.8"
 

src/trio/_core/_tests/test_guest_mode.py

@@ -25,7 +25,6 @@
 
 import pytest
 from outcome import Outcome
-from pytest import MonkeyPatch, WarningsRecorder
 
 import trio
 import trio.testing
@@ -171,17 +170,16 @@ async def early_task() -> None:
     assert res == "ok"
     assert set(record) == {"system task ran", "main task ran", "run_sync_soon cb ran"}
 
+    class BadClock:
+        def start_clock(self) -> NoReturn:
+            raise ValueError("whoops")
+
+    def after_start_never_runs() -> None:  # pragma: no cover
+        pytest.fail("shouldn't get here")
+
     # Errors during initialization (which can only be TrioInternalErrors)
     # are raised out of start_guest_run, not out of the done_callback
     with pytest.raises(trio.TrioInternalError):
-
-        class BadClock:
-            def start_clock(self) -> NoReturn:
-                raise ValueError("whoops")
-
-        def after_start_never_runs() -> None:  # pragma: no cover
-            pytest.fail("shouldn't get here")
-
         trivial_guest_run(
             trio_main, clock=BadClock(), in_host_after_start=after_start_never_runs
         )
@@ -527,7 +525,7 @@ async def aio_pingpong(
 
 
 def test_guest_mode_internal_errors(
-    monkeypatch: MonkeyPatch, recwarn: WarningsRecorder
+    monkeypatch: pytest.MonkeyPatch, recwarn: pytest.WarningsRecorder
 ) -> None:
     with monkeypatch.context() as m:
 

src/trio/_core/_tests/test_instrumentation.py

@@ -255,7 +255,7 @@ def after_run(self) -> NoReturn:
             raise ValueError("oops")
 
     async def main() -> None:
-        with pytest.raises(ValueError):
+        with pytest.raises(ValueError, match="^oops$"):
             _core.add_instrument(EvilInstrument())
 
         # Make sure the instrument is fully removed from the per-method lists

src/trio/_core/_tests/test_io.py

@@ -319,7 +319,10 @@ async def test_wait_on_invalid_object() -> None:
             fileno = s.fileno()
         # We just closed the socket and don't do anything else in between, so
         # we can be confident that the fileno hasn't be reassigned.
-        with pytest.raises(OSError):
+        with pytest.raises(
+            OSError,
+            match=r"^\[\w+ \d+] (Bad file descriptor|An operation was attempted on something that is not a socket)$",
+        ):
             await wait(fileno)
 
 

src/trio/_core/_tests/test_local.py

@@ -57,13 +57,13 @@ async def reset_check() -> None:
         t2.reset(token2)
         assert t2.get() == "dogfish"
 
-        with pytest.raises(ValueError):
+        with pytest.raises(ValueError, match="^token has already been used$"):
             t2.reset(token2)
 
         token3 = t3.set("basculin")
         assert t3.get() == "basculin"
 
-        with pytest.raises(ValueError):
+        with pytest.raises(ValueError, match="^token is not for us$"):
             t1.reset(token3)
 
     run(reset_check)

src/trio/_core/_tests/test_mock_clock.py

@@ -20,14 +20,14 @@ def test_mock_clock() -> None:
     assert c.current_time() == 0
     c.jump(1.2)
     assert c.current_time() == 1.2
-    with pytest.raises(ValueError):
+    with pytest.raises(ValueError, match="^time can't go backwards$"):
         c.jump(-1)
     assert c.current_time() == 1.2
     assert c.deadline_to_sleep_time(1.1) == 0
     assert c.deadline_to_sleep_time(1.2) == 0
     assert c.deadline_to_sleep_time(1.3) > 999999
 
-    with pytest.raises(ValueError):
+    with pytest.raises(ValueError, match="^rate must be >= 0$"):
         c.rate = -1
     assert c.rate == 0
 

src/trio/_core/_tests/test_multierror.py

@@ -136,7 +136,7 @@ async def test_MultiErrorNotHashable() -> None:
     assert exc1 != exc2
     assert exc1 != exc3
 
-    with pytest.raises(MultiError):
+    with pytest.raises(MultiError):  # noqa: PT012
         async with open_nursery() as nursery:
             nursery.start_soon(raise_nothashable, 42)
             nursery.start_soon(raise_nothashable, 4242)
@@ -331,36 +331,35 @@ def simple_filter(exc):
     assert new_m.__context__ is None
 
     # check preservation of __cause__ and __context__
-    v = ValueError()
+    v = ValueError("waffles are great")
     v.__cause__ = KeyError()
-    with pytest.raises(ValueError) as excinfo:
+    with pytest.raises(ValueError, match="^waffles are great$") as excinfo:
         with pytest.warns(TrioDeprecationWarning), MultiError.catch(lambda exc: exc):
             raise v
     assert isinstance(excinfo.value.__cause__, KeyError)
 
-    v = ValueError()
+    v = ValueError("mushroom soup")
     context = KeyError()
     v.__context__ = context
-    with pytest.raises(ValueError) as excinfo:
+    with pytest.raises(ValueError, match="^mushroom soup$") as excinfo:
         with pytest.warns(TrioDeprecationWarning), MultiError.catch(lambda exc: exc):
             raise v
     assert excinfo.value.__context__ is context
     assert not excinfo.value.__suppress_context__
 
     for suppress_context in [True, False]:
-        v = ValueError()
+        v = ValueError("unique text")
         context = KeyError()
         v.__context__ = context
         v.__suppress_context__ = suppress_context
         distractor = RuntimeError()
-        with pytest.raises(ValueError) as excinfo:
 
-            def catch_RuntimeError(exc):
-                if isinstance(exc, RuntimeError):
-                    return None
-                else:
-                    return exc
+        def catch_RuntimeError(exc: Exception) -> Exception | None:
+            if isinstance(exc, RuntimeError):
+                return None
+            return exc
 
+        with pytest.raises(ValueError, match="^unique text$") as excinfo:  # noqa: PT012
             with pytest.warns(TrioDeprecationWarning):
                 with MultiError.catch(catch_RuntimeError):
                     raise MultiError([v, distractor])

src/trio/_core/_tests/test_parking_lot.py

@@ -78,7 +78,9 @@ async def waiter(i: int, lot: ParkingLot) -> None:
         )
         lot.unpark_all()
 
-    with pytest.raises(ValueError):
+    with pytest.raises(
+        ValueError, match=r"^Cannot pop a non-integer number of tasks\.$"
+    ):
         lot.unpark(count=1.5)