_synctest.py 文件源码

def _collectWarnings(observeWarning, f, *args, **kwargs):
    """
    Call C{f} with C{args} positional arguments and C{kwargs} keyword arguments
    and collect all warnings which are emitted as a result in a list.

    @param observeWarning: A callable which will be invoked with a L{_Warning}
        instance each time a warning is emitted.

    @return: The return value of C{f(*args, **kwargs)}.
    """
    def showWarning(message, category, filename, lineno, file=None, line=None):
        assert isinstance(message, Warning)
        observeWarning(_Warning(
                str(message), category, filename, lineno))

    # Disable the per-module cache for every module otherwise if the warning
    # which the caller is expecting us to collect was already emitted it won't
    # be re-emitted by the call to f which happens below.
    _setWarningRegistryToNone(sys.modules)

    origFilters = warnings.filters[:]
    origShow = warnings.showwarning
    warnings.simplefilter('always')
    try:
        warnings.showwarning = showWarning
        result = f(*args, **kwargs)
    finally:
        warnings.filters[:] = origFilters
        warnings.showwarning = origShow
    return result