Fix type of pytest.warns, and fix check_untyped_defs in test_recwarn

The expected_warning is optional.

src/_pytest/recwarn.py

@@ -57,7 +57,7 @@ def deprecated_call(func=None, *args, **kwargs):
 
 @overload
 def warns(
-    expected_warning: Union["Type[Warning]", Tuple["Type[Warning]", ...]],
+    expected_warning: Optional[Union["Type[Warning]", Tuple["Type[Warning]", ...]]],
     *,
     match: "Optional[Union[str, Pattern]]" = ...
 ) -> "WarningsChecker":
@@ -66,7 +66,7 @@ def warns(
 
 @overload  # noqa: F811
 def warns(  # noqa: F811
-    expected_warning: Union["Type[Warning]", Tuple["Type[Warning]", ...]],
+    expected_warning: Optional[Union["Type[Warning]", Tuple["Type[Warning]", ...]]],
     func: Callable,
     *args: Any,
     match: Optional[Union[str, "Pattern"]] = ...,
@@ -76,7 +76,7 @@ def warns(  # noqa: F811
 
 
 def warns(  # noqa: F811
-    expected_warning: Union["Type[Warning]", Tuple["Type[Warning]", ...]],
+    expected_warning: Optional[Union["Type[Warning]", Tuple["Type[Warning]", ...]]],
     *args: Any,
     match: Optional[Union[str, "Pattern"]] = None,
     **kwargs: Any

testing/test_recwarn.py

@@ -1,17 +1,19 @@
 import re
 import warnings
+from typing import Optional
 
 import pytest
+from _pytest.outcomes import Failed
 from _pytest.recwarn import WarningsRecorder
 
 
-def test_recwarn_stacklevel(recwarn):
+def test_recwarn_stacklevel(recwarn: WarningsRecorder) -> None:
     warnings.warn("hello")
     warn = recwarn.pop()
     assert warn.filename == __file__
 
 
-def test_recwarn_functional(testdir):
+def test_recwarn_functional(testdir) -> None:
     testdir.makepyfile(
         """
         import warnings
@@ -26,7 +28,7 @@ def test_recwarn_functional(testdir):
 
 
 class TestWarningsRecorderChecker:
-    def test_recording(self):
+    def test_recording(self) -> None:
         rec = WarningsRecorder()
         with rec:
             assert not rec.list
@@ -42,23 +44,23 @@ class TestWarningsRecorderChecker:
             assert values is rec.list
             pytest.raises(AssertionError, rec.pop)
 
-    def test_warn_stacklevel(self):
+    def test_warn_stacklevel(self) -> None:
         """#4243"""
         rec = WarningsRecorder()
         with rec:
             warnings.warn("test", DeprecationWarning, 2)
 
-    def test_typechecking(self):
+    def test_typechecking(self) -> None:
         from _pytest.recwarn import WarningsChecker
 
         with pytest.raises(TypeError):
-            WarningsChecker(5)
+            WarningsChecker(5)  # type: ignore
         with pytest.raises(TypeError):
-            WarningsChecker(("hi", RuntimeWarning))
+            WarningsChecker(("hi", RuntimeWarning))  # type: ignore
         with pytest.raises(TypeError):
-            WarningsChecker([DeprecationWarning, RuntimeWarning])
+            WarningsChecker([DeprecationWarning, RuntimeWarning])  # type: ignore
 
-    def test_invalid_enter_exit(self):
+    def test_invalid_enter_exit(self) -> None:
         # wrap this test in WarningsRecorder to ensure warning state gets reset
         with WarningsRecorder():
             with pytest.raises(RuntimeError):
@@ -75,50 +77,52 @@ class TestWarningsRecorderChecker:
 class TestDeprecatedCall:
     """test pytest.deprecated_call()"""
 
-    def dep(self, i, j=None):
+    def dep(self, i: int, j: Optional[int] = None) -> int:
         if i == 0:
             warnings.warn("is deprecated", DeprecationWarning, stacklevel=1)
         return 42
 
-    def dep_explicit(self, i):
+    def dep_explicit(self, i: int) -> None:
         if i == 0:
             warnings.warn_explicit(
                 "dep_explicit", category=DeprecationWarning, filename="hello", lineno=3
             )
 
-    def test_deprecated_call_raises(self):
+    def test_deprecated_call_raises(self) -> None:
-        with pytest.raises(pytest.fail.Exception, match="No warnings of type"):
+        with pytest.raises(Failed, match="No warnings of type"):
             pytest.deprecated_call(self.dep, 3, 5)
 
-    def test_deprecated_call(self):
+    def test_deprecated_call(self) -> None:
         pytest.deprecated_call(self.dep, 0, 5)
 
-    def test_deprecated_call_ret(self):
+    def test_deprecated_call_ret(self) -> None:
         ret = pytest.deprecated_call(self.dep, 0)
         assert ret == 42
 
-    def test_deprecated_call_preserves(self):
+    def test_deprecated_call_preserves(self) -> None:
-        onceregistry = warnings.onceregistry.copy()
+        # Type ignored because `onceregistry` and `filters` are not
-        filters = warnings.filters[:]
+        # documented API.
+        onceregistry = warnings.onceregistry.copy()  # type: ignore
+        filters = warnings.filters[:]  # type: ignore
         warn = warnings.warn
         warn_explicit = warnings.warn_explicit
         self.test_deprecated_call_raises()
         self.test_deprecated_call()
-        assert onceregistry == warnings.onceregistry
+        assert onceregistry == warnings.onceregistry  # type: ignore
-        assert filters == warnings.filters
+        assert filters == warnings.filters  # type: ignore
         assert warn is warnings.warn
         assert warn_explicit is warnings.warn_explicit
 
-    def test_deprecated_explicit_call_raises(self):
+    def test_deprecated_explicit_call_raises(self) -> None:
-        with pytest.raises(pytest.fail.Exception):
+        with pytest.raises(Failed):
             pytest.deprecated_call(self.dep_explicit, 3)
 
-    def test_deprecated_explicit_call(self):
+    def test_deprecated_explicit_call(self) -> None:
         pytest.deprecated_call(self.dep_explicit, 0)
         pytest.deprecated_call(self.dep_explicit, 0)
 
     @pytest.mark.parametrize("mode", ["context_manager", "call"])
-    def test_deprecated_call_no_warning(self, mode):
+    def test_deprecated_call_no_warning(self, mode) -> None:
         """Ensure deprecated_call() raises the expected failure when its block/function does
         not raise a deprecation warning.
         """
@@ -127,7 +131,7 @@ class TestDeprecatedCall:
             pass
 
         msg = "No warnings of type (.*DeprecationWarning.*, .*PendingDeprecationWarning.*)"
-        with pytest.raises(pytest.fail.Exception, match=msg):
+        with pytest.raises(Failed, match=msg):
             if mode == "call":
                 pytest.deprecated_call(f)
             else:
@@ -140,7 +144,7 @@ class TestDeprecatedCall:
     @pytest.mark.parametrize("mode", ["context_manager", "call"])
     @pytest.mark.parametrize("call_f_first", [True, False])
     @pytest.mark.filterwarnings("ignore")
-    def test_deprecated_call_modes(self, warning_type, mode, call_f_first):
+    def test_deprecated_call_modes(self, warning_type, mode, call_f_first) -> None:
         """Ensure deprecated_call() captures a deprecation warning as expected inside its
         block/function.
         """
@@ -159,7 +163,7 @@ class TestDeprecatedCall:
                 assert f() == 10
 
     @pytest.mark.parametrize("mode", ["context_manager", "call"])
-    def test_deprecated_call_exception_is_raised(self, mode):
+    def test_deprecated_call_exception_is_raised(self, mode) -> None:
         """If the block of the code being tested by deprecated_call() raises an exception,
         it must raise the exception undisturbed.
         """
@@ -174,7 +178,7 @@ class TestDeprecatedCall:
                 with pytest.deprecated_call():
                     f()
 
-    def test_deprecated_call_specificity(self):
+    def test_deprecated_call_specificity(self) -> None:
         other_warnings = [
             Warning,
             UserWarning,
@@ -189,40 +193,40 @@ class TestDeprecatedCall:
             def f():
                 warnings.warn(warning("hi"))
 
-            with pytest.raises(pytest.fail.Exception):
+            with pytest.raises(Failed):
                 pytest.deprecated_call(f)
-            with pytest.raises(pytest.fail.Exception):
+            with pytest.raises(Failed):
                 with pytest.deprecated_call():
                     f()
 
-    def test_deprecated_call_supports_match(self):
+    def test_deprecated_call_supports_match(self) -> None:
         with pytest.deprecated_call(match=r"must be \d+$"):
             warnings.warn("value must be 42", DeprecationWarning)
 
-        with pytest.raises(pytest.fail.Exception):
+        with pytest.raises(Failed):
             with pytest.deprecated_call(match=r"must be \d+$"):
                 warnings.warn("this is not here", DeprecationWarning)
 
 
 class TestWarns:
-    def test_check_callable(self):
+    def test_check_callable(self) -> None:
         source = "warnings.warn('w1', RuntimeWarning)"
         with pytest.raises(TypeError, match=r".* must be callable"):
-            pytest.warns(RuntimeWarning, source)
+            pytest.warns(RuntimeWarning, source)  # type: ignore
 
-    def test_several_messages(self):
+    def test_several_messages(self) -> None:
         # different messages, b/c Python suppresses multiple identical warnings
         pytest.warns(RuntimeWarning, lambda: warnings.warn("w1", RuntimeWarning))
-        with pytest.raises(pytest.fail.Exception):
+        with pytest.raises(Failed):
             pytest.warns(UserWarning, lambda: warnings.warn("w2", RuntimeWarning))
         pytest.warns(RuntimeWarning, lambda: warnings.warn("w3", RuntimeWarning))
 
-    def test_function(self):
+    def test_function(self) -> None:
         pytest.warns(
             SyntaxWarning, lambda msg: warnings.warn(msg, SyntaxWarning), "syntax"
         )
 
-    def test_warning_tuple(self):
+    def test_warning_tuple(self) -> None:
         pytest.warns(
             (RuntimeWarning, SyntaxWarning), lambda: warnings.warn("w1", RuntimeWarning)
         )
@@ -230,21 +234,21 @@ class TestWarns:
             (RuntimeWarning, SyntaxWarning), lambda: warnings.warn("w2", SyntaxWarning)
         )
         pytest.raises(
-            pytest.fail.Exception,
+            Failed,
             lambda: pytest.warns(
                 (RuntimeWarning, SyntaxWarning),
                 lambda: warnings.warn("w3", UserWarning),
             ),
         )
 
-    def test_as_contextmanager(self):
+    def test_as_contextmanager(self) -> None:
         with pytest.warns(RuntimeWarning):
             warnings.warn("runtime", RuntimeWarning)
 
         with pytest.warns(UserWarning):
             warnings.warn("user", UserWarning)
 
-        with pytest.raises(pytest.fail.Exception) as excinfo:
+        with pytest.raises(Failed) as excinfo:
             with pytest.warns(RuntimeWarning):
                 warnings.warn("user", UserWarning)
         excinfo.match(
@@ -252,7 +256,7 @@ class TestWarns:
             r"The list of emitted warnings is: \[UserWarning\('user',?\)\]."
         )
 
-        with pytest.raises(pytest.fail.Exception) as excinfo:
+        with pytest.raises(Failed) as excinfo:
             with pytest.warns(UserWarning):
                 warnings.warn("runtime", RuntimeWarning)
         excinfo.match(
@@ -260,7 +264,7 @@ class TestWarns:
             r"The list of emitted warnings is: \[RuntimeWarning\('runtime',?\)\]."
         )
 
-        with pytest.raises(pytest.fail.Exception) as excinfo:
+        with pytest.raises(Failed) as excinfo:
             with pytest.warns(UserWarning):
                 pass
         excinfo.match(
@@ -269,7 +273,7 @@ class TestWarns:
         )
 
         warning_classes = (UserWarning, FutureWarning)
-        with pytest.raises(pytest.fail.Exception) as excinfo:
+        with pytest.raises(Failed) as excinfo:
             with pytest.warns(warning_classes) as warninfo:
                 warnings.warn("runtime", RuntimeWarning)
                 warnings.warn("import", ImportWarning)
@@ -286,14 +290,14 @@ class TestWarns:
             )
         )
 
-    def test_record(self):
+    def test_record(self) -> None:
         with pytest.warns(UserWarning) as record:
             warnings.warn("user", UserWarning)
 
         assert len(record) == 1
         assert str(record[0].message) == "user"
 
-    def test_record_only(self):
+    def test_record_only(self) -> None:
         with pytest.warns(None) as record:
             warnings.warn("user", UserWarning)
             warnings.warn("runtime", RuntimeWarning)
@@ -302,7 +306,7 @@ class TestWarns:
         assert str(record[0].message) == "user"
         assert str(record[1].message) == "runtime"
 
-    def test_record_by_subclass(self):
+    def test_record_by_subclass(self) -> None:
         with pytest.warns(Warning) as record:
             warnings.warn("user", UserWarning)
             warnings.warn("runtime", RuntimeWarning)
@@ -325,7 +329,7 @@ class TestWarns:
         assert str(record[0].message) == "user"
         assert str(record[1].message) == "runtime"
 
-    def test_double_test(self, testdir):
+    def test_double_test(self, testdir) -> None:
         """If a test is run again, the warning should still be raised"""
         testdir.makepyfile(
             """
@@ -341,32 +345,32 @@ class TestWarns:
         result = testdir.runpytest()
         result.stdout.fnmatch_lines(["*2 passed in*"])
 
-    def test_match_regex(self):
+    def test_match_regex(self) -> None:
         with pytest.warns(UserWarning, match=r"must be \d+$"):
             warnings.warn("value must be 42", UserWarning)
 
-        with pytest.raises(pytest.fail.Exception):
+        with pytest.raises(Failed):
             with pytest.warns(UserWarning, match=r"must be \d+$"):
                 warnings.warn("this is not here", UserWarning)
 
-        with pytest.raises(pytest.fail.Exception):
+        with pytest.raises(Failed):
             with pytest.warns(FutureWarning, match=r"must be \d+$"):
                 warnings.warn("value must be 42", UserWarning)
 
-    def test_one_from_multiple_warns(self):
+    def test_one_from_multiple_warns(self) -> None:
         with pytest.warns(UserWarning, match=r"aaa"):
             warnings.warn("cccccccccc", UserWarning)
             warnings.warn("bbbbbbbbbb", UserWarning)
             warnings.warn("aaaaaaaaaa", UserWarning)
 
-    def test_none_of_multiple_warns(self):
+    def test_none_of_multiple_warns(self) -> None:
-        with pytest.raises(pytest.fail.Exception):
+        with pytest.raises(Failed):
             with pytest.warns(UserWarning, match=r"aaa"):
                 warnings.warn("bbbbbbbbbb", UserWarning)
                 warnings.warn("cccccccccc", UserWarning)
 
     @pytest.mark.filterwarnings("ignore")
-    def test_can_capture_previously_warned(self):
+    def test_can_capture_previously_warned(self) -> None:
         def f():
             warnings.warn(UserWarning("ohai"))
             return 10
@@ -375,8 +379,8 @@ class TestWarns:
         assert pytest.warns(UserWarning, f) == 10
         assert pytest.warns(UserWarning, f) == 10
 
-    def test_warns_context_manager_with_kwargs(self):
+    def test_warns_context_manager_with_kwargs(self) -> None:
         with pytest.raises(TypeError) as excinfo:
-            with pytest.warns(UserWarning, foo="bar"):
+            with pytest.warns(UserWarning, foo="bar"):  # type: ignore
                 pass
         assert "Unexpected keyword arguments" in str(excinfo.value)