123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296 |
- """Record warnings during test function execution."""
- import re
- import warnings
- from types import TracebackType
- from typing import Any
- from typing import Callable
- from typing import Generator
- from typing import Iterator
- from typing import List
- from typing import Optional
- from typing import overload
- from typing import Pattern
- from typing import Tuple
- from typing import Type
- from typing import TypeVar
- from typing import Union
- from _pytest.compat import final
- from _pytest.deprecated import check_ispytest
- from _pytest.deprecated import WARNS_NONE_ARG
- from _pytest.fixtures import fixture
- from _pytest.outcomes import fail
- T = TypeVar("T")
- @fixture
- def recwarn() -> Generator["WarningsRecorder", None, None]:
- """Return a :class:`WarningsRecorder` instance that records all warnings emitted by test functions.
- See https://docs.python.org/library/how-to/capture-warnings.html for information
- on warning categories.
- """
- wrec = WarningsRecorder(_ispytest=True)
- with wrec:
- warnings.simplefilter("default")
- yield wrec
- @overload
- def deprecated_call(
- *, match: Optional[Union[str, Pattern[str]]] = ...
- ) -> "WarningsRecorder":
- ...
- @overload
- def deprecated_call(func: Callable[..., T], *args: Any, **kwargs: Any) -> T:
- ...
- def deprecated_call(
- func: Optional[Callable[..., Any]] = None, *args: Any, **kwargs: Any
- ) -> Union["WarningsRecorder", Any]:
- """Assert that code produces a ``DeprecationWarning`` or ``PendingDeprecationWarning``.
- This function can be used as a context manager::
- >>> import warnings
- >>> def api_call_v2():
- ... warnings.warn('use v3 of this api', DeprecationWarning)
- ... return 200
- >>> import pytest
- >>> with pytest.deprecated_call():
- ... assert api_call_v2() == 200
- It can also be used by passing a function and ``*args`` and ``**kwargs``,
- in which case it will ensure calling ``func(*args, **kwargs)`` produces one of
- the warnings types above. The return value is the return value of the function.
- In the context manager form you may use the keyword argument ``match`` to assert
- that the warning matches a text or regex.
- The context manager produces a list of :class:`warnings.WarningMessage` objects,
- one for each warning raised.
- """
- __tracebackhide__ = True
- if func is not None:
- args = (func,) + args
- return warns((DeprecationWarning, PendingDeprecationWarning), *args, **kwargs)
- @overload
- def warns(
- expected_warning: Union[Type[Warning], Tuple[Type[Warning], ...]] = ...,
- *,
- match: Optional[Union[str, Pattern[str]]] = ...,
- ) -> "WarningsChecker":
- ...
- @overload
- def warns(
- expected_warning: Union[Type[Warning], Tuple[Type[Warning], ...]],
- func: Callable[..., T],
- *args: Any,
- **kwargs: Any,
- ) -> T:
- ...
- def warns(
- expected_warning: Union[Type[Warning], Tuple[Type[Warning], ...]] = Warning,
- *args: Any,
- match: Optional[Union[str, Pattern[str]]] = None,
- **kwargs: Any,
- ) -> Union["WarningsChecker", Any]:
- r"""Assert that code raises a particular class of warning.
- Specifically, the parameter ``expected_warning`` can be a warning class or
- sequence of warning classes, and the inside the ``with`` block must issue a warning of that class or
- classes.
- This helper produces a list of :class:`warnings.WarningMessage` objects,
- one for each warning raised.
- This function can be used as a context manager, or any of the other ways
- :func:`pytest.raises` can be used::
- >>> import pytest
- >>> with pytest.warns(RuntimeWarning):
- ... warnings.warn("my warning", RuntimeWarning)
- In the context manager form you may use the keyword argument ``match`` to assert
- that the warning matches a text or regex::
- >>> with pytest.warns(UserWarning, match='must be 0 or None'):
- ... warnings.warn("value must be 0 or None", UserWarning)
- >>> with pytest.warns(UserWarning, match=r'must be \d+$'):
- ... warnings.warn("value must be 42", UserWarning)
- >>> with pytest.warns(UserWarning, match=r'must be \d+$'):
- ... warnings.warn("this is not here", UserWarning)
- Traceback (most recent call last):
- ...
- Failed: DID NOT WARN. No warnings of type ...UserWarning... were emitted...
- """
- __tracebackhide__ = True
- if not args:
- if kwargs:
- msg = "Unexpected keyword arguments passed to pytest.warns: "
- msg += ", ".join(sorted(kwargs))
- msg += "\nUse context-manager form instead?"
- raise TypeError(msg)
- return WarningsChecker(expected_warning, match_expr=match, _ispytest=True)
- else:
- func = args[0]
- if not callable(func):
- raise TypeError(f"{func!r} object (type: {type(func)}) must be callable")
- with WarningsChecker(expected_warning, _ispytest=True):
- return func(*args[1:], **kwargs)
- class WarningsRecorder(warnings.catch_warnings):
- """A context manager to record raised warnings.
- Adapted from `warnings.catch_warnings`.
- """
- def __init__(self, *, _ispytest: bool = False) -> None:
- check_ispytest(_ispytest)
- # Type ignored due to the way typeshed handles warnings.catch_warnings.
- super().__init__(record=True) # type: ignore[call-arg]
- self._entered = False
- self._list: List[warnings.WarningMessage] = []
- @property
- def list(self) -> List["warnings.WarningMessage"]:
- """The list of recorded warnings."""
- return self._list
- def __getitem__(self, i: int) -> "warnings.WarningMessage":
- """Get a recorded warning by index."""
- return self._list[i]
- def __iter__(self) -> Iterator["warnings.WarningMessage"]:
- """Iterate through the recorded warnings."""
- return iter(self._list)
- def __len__(self) -> int:
- """The number of recorded warnings."""
- return len(self._list)
- def pop(self, cls: Type[Warning] = Warning) -> "warnings.WarningMessage":
- """Pop the first recorded warning, raise exception if not exists."""
- for i, w in enumerate(self._list):
- if issubclass(w.category, cls):
- return self._list.pop(i)
- __tracebackhide__ = True
- raise AssertionError("%r not found in warning list" % cls)
- def clear(self) -> None:
- """Clear the list of recorded warnings."""
- self._list[:] = []
- # Type ignored because it doesn't exactly warnings.catch_warnings.__enter__
- # -- it returns a List but we only emulate one.
- def __enter__(self) -> "WarningsRecorder": # type: ignore
- if self._entered:
- __tracebackhide__ = True
- raise RuntimeError("Cannot enter %r twice" % self)
- _list = super().__enter__()
- # record=True means it's None.
- assert _list is not None
- self._list = _list
- warnings.simplefilter("always")
- return self
- def __exit__(
- self,
- exc_type: Optional[Type[BaseException]],
- exc_val: Optional[BaseException],
- exc_tb: Optional[TracebackType],
- ) -> None:
- if not self._entered:
- __tracebackhide__ = True
- raise RuntimeError("Cannot exit %r without entering first" % self)
- super().__exit__(exc_type, exc_val, exc_tb)
- # Built-in catch_warnings does not reset entered state so we do it
- # manually here for this context manager to become reusable.
- self._entered = False
- @final
- class WarningsChecker(WarningsRecorder):
- def __init__(
- self,
- expected_warning: Optional[
- Union[Type[Warning], Tuple[Type[Warning], ...]]
- ] = Warning,
- match_expr: Optional[Union[str, Pattern[str]]] = None,
- *,
- _ispytest: bool = False,
- ) -> None:
- check_ispytest(_ispytest)
- super().__init__(_ispytest=True)
- msg = "exceptions must be derived from Warning, not %s"
- if expected_warning is None:
- warnings.warn(WARNS_NONE_ARG, stacklevel=4)
- expected_warning_tup = None
- elif isinstance(expected_warning, tuple):
- for exc in expected_warning:
- if not issubclass(exc, Warning):
- raise TypeError(msg % type(exc))
- expected_warning_tup = expected_warning
- elif issubclass(expected_warning, Warning):
- expected_warning_tup = (expected_warning,)
- else:
- raise TypeError(msg % type(expected_warning))
- self.expected_warning = expected_warning_tup
- self.match_expr = match_expr
- def __exit__(
- self,
- exc_type: Optional[Type[BaseException]],
- exc_val: Optional[BaseException],
- exc_tb: Optional[TracebackType],
- ) -> None:
- super().__exit__(exc_type, exc_val, exc_tb)
- __tracebackhide__ = True
- # only check if we're not currently handling an exception
- if exc_type is None and exc_val is None and exc_tb is None:
- if self.expected_warning is not None:
- if not any(issubclass(r.category, self.expected_warning) for r in self):
- __tracebackhide__ = True
- fail(
- "DID NOT WARN. No warnings of type {} were emitted. "
- "The list of emitted warnings is: {}.".format(
- self.expected_warning, [each.message for each in self]
- )
- )
- elif self.match_expr is not None:
- for r in self:
- if issubclass(r.category, self.expected_warning):
- if re.compile(self.match_expr).search(str(r.message)):
- break
- else:
- fail(
- "DID NOT WARN. No warnings of type {} matching"
- " ('{}') were emitted. The list of emitted warnings"
- " is: {}.".format(
- self.expected_warning,
- self.match_expr,
- [each.message for each in self],
- )
- )
|