from contextlib import contextmanager
import sys
import traceback
import pytest
@contextmanager
def capture_exceptions():
"""
Context manager that captures exceptions that happen insides its context,
and returns them as a list of (type, value, traceback) after the
context ends.
"""
manager = _QtExceptionCaptureManager()
manager.start()
try:
yield manager.exceptions
finally:
manager.finish()
class _QtExceptionCaptureManager(object):
"""
Manages exception capture context.
"""
def __init__(self):
self.old_hook = None
self.exceptions = []
def start(self):
"""Start exception capturing by installing a hook into sys.excepthook
that records exceptions received into ``self.exceptions``.
"""
def hook(type_, value, tback):
self.exceptions.append((type_, value, tback))
sys.stderr.write(format_captured_exceptions([(type_, value, tback)]))
self.old_hook = sys.excepthook
sys.excepthook = hook
def finish(self):
"""Stop exception capturing, restoring the original hook.
Can be called multiple times.
"""
if self.old_hook is not None:
sys.excepthook = self.old_hook
self.old_hook = None
def fail_if_exceptions_occurred(self, when):
"""calls pytest.fail() with an informative message if exceptions
have been captured so far. Before pytest.fail() is called, also
finish capturing.
"""
if self.exceptions:
self.finish()
exceptions = self.exceptions
self.exceptions = []
prefix = '%s ERROR: ' % when
pytest.fail(prefix + format_captured_exceptions(exceptions),
pytrace=False)
def format_captured_exceptions(exceptions):
"""
Formats exceptions given as (type, value, traceback) into a string
suitable to display as a test failure.
"""
message = 'Qt exceptions in virtual methods:\n'
message += '_' * 80 + '\n'
for (exc_type, value, tback) in exceptions:
message += ''.join(traceback.format_tb(tback)) + '\n'
message += '%s: %s\n' % (exc_type.__name__, value)
message += '_' * 80 + '\n'
return message
def _is_exception_capture_enabled(item):
"""returns if exception capture is disabled for the given test item.
"""
disabled = item.get_marker('qt_no_exception_capture') or \
item.config.getini('qt_no_exception_capture')
return not disabled
[docs]class TimeoutError(Exception):
"""
.. versionadded:: 2.1
Exception thrown by :class:`pytestqt.qtbot.QtBot` methods.
.. note::
In versions prior to ``2.1``, this exception was called ``SignalTimeoutError``.
An alias is kept for backward compatibility.
"""
pass
# backward compatibility alias
SignalTimeoutError = TimeoutError