blob: a89474c036aa5b3a06d89b66c4ed634b48b82204 [file] [log] [blame]
""" recording warnings during test function execution. """
import inspect
import _pytest._code
import py
import sys
import warnings
import pytest
def recwarn(request):
"""Return a WarningsRecorder instance that provides these methods:
* ``pop(category=None)``: return last warning matching the category.
* ``clear()``: clear list of warnings
See for information
on warning categories.
wrec = WarningsRecorder()
with wrec:
yield wrec
def pytest_namespace():
return {'deprecated_call': deprecated_call,
'warns': warns}
def deprecated_call(func=None, *args, **kwargs):
""" assert that calling ``func(*args, **kwargs)`` triggers a
``DeprecationWarning`` or ``PendingDeprecationWarning``.
This function can be used as a context manager::
>>> with deprecated_call():
... myobject.deprecated_method()
Note: we cannot use WarningsRecorder here because it is still subject
to the mechanism that prevents warnings of the same type from being
triggered twice for the same module. See #1190.
if not func:
return WarningsChecker(expected_warning=DeprecationWarning)
categories = []
def warn_explicit(message, category, *args, **kwargs):
old_warn_explicit(message, category, *args, **kwargs)
def warn(message, category=None, *args, **kwargs):
if isinstance(message, Warning):
old_warn(message, category, *args, **kwargs)
old_warn = warnings.warn
old_warn_explicit = warnings.warn_explicit
warnings.warn_explicit = warn_explicit
warnings.warn = warn
ret = func(*args, **kwargs)
warnings.warn_explicit = old_warn_explicit
warnings.warn = old_warn
deprecation_categories = (DeprecationWarning, PendingDeprecationWarning)
if not any(issubclass(c, deprecation_categories) for c in categories):
__tracebackhide__ = True
raise AssertionError("%r did not produce DeprecationWarning" % (func,))
return ret
def warns(expected_warning, *args, **kwargs):
"""Assert that code raises a particular class of warning.
Specifically, the input @expected_warning can be a warning class or
tuple of warning classes, and the code must return that warning
(if a single class) or one of those warnings (if a tuple).
This helper produces a list of ``warnings.WarningMessage`` objects,
one for each warning raised.
This function can be used as a context manager, or any of the other ways
``pytest.raises`` can be used::
>>> with warns(RuntimeWarning):
... warnings.warn("my warning", RuntimeWarning)
wcheck = WarningsChecker(expected_warning)
if not args:
return wcheck
elif isinstance(args[0], str):
code, = args
assert isinstance(code, str)
frame = sys._getframe(1)
loc = frame.f_locals.copy()
with wcheck:
code = _pytest._code.Source(code).compile()
py.builtin.exec_(code, frame.f_globals, loc)
func = args[0]
with wcheck:
return func(*args[1:], **kwargs)
class RecordedWarning(object):
def __init__(self, message, category, filename, lineno, file, line):
self.message = message
self.category = category
self.filename = filename
self.lineno = lineno
self.file = file
self.line = line
class WarningsRecorder(object):
"""A context manager to record raised warnings.
Adapted from `warnings.catch_warnings`.
def __init__(self, module=None):
self._module = sys.modules['warnings'] if module is None else module
self._entered = False
self._list = []
def list(self):
"""The list of recorded warnings."""
return self._list
def __getitem__(self, i):
"""Get a recorded warning by index."""
return self._list[i]
def __iter__(self):
"""Iterate through the recorded warnings."""
return iter(self._list)
def __len__(self):
"""The number of recorded warnings."""
return len(self._list)
def pop(self, cls=Warning):
"""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):
"""Clear the list of recorded warnings."""
self._list[:] = []
def __enter__(self):
if self._entered:
__tracebackhide__ = True
raise RuntimeError("Cannot enter %r twice" % self)
self._entered = True
self._filters = self._module.filters
self._module.filters = self._filters[:]
self._showwarning = self._module.showwarning
def showwarning(message, category, filename, lineno,
file=None, line=None):
message, category, filename, lineno, file, line))
# still perform old showwarning functionality
message, category, filename, lineno, file=file, line=line)
self._module.showwarning = showwarning
# allow the same warning to be raised more than once
return self
def __exit__(self, *exc_info):
if not self._entered:
__tracebackhide__ = True
raise RuntimeError("Cannot exit %r without entering first" % self)
self._module.filters = self._filters
self._module.showwarning = self._showwarning
class WarningsChecker(WarningsRecorder):
def __init__(self, expected_warning=None, module=None):
super(WarningsChecker, self).__init__(module=module)
msg = ("exceptions must be old-style classes or "
"derived from Warning, not %s")
if isinstance(expected_warning, tuple):
for exc in expected_warning:
if not inspect.isclass(exc):
raise TypeError(msg % type(exc))
elif inspect.isclass(expected_warning):
expected_warning = (expected_warning,)
elif expected_warning is not None:
raise TypeError(msg % type(expected_warning))
self.expected_warning = expected_warning
def __exit__(self, *exc_info):
super(WarningsChecker, self).__exit__(*exc_info)
# only check if we're not currently handling an exception
if all(a is None for a in exc_info):
if self.expected_warning is not None:
if not any(r.category in self.expected_warning for r in self):
__tracebackhide__ = True"DID NOT WARN")