test_warnings.py 文件源码

def warnings_state(module):
    """Use a specific warnings implementation in warning_tests."""
    global __warningregistry__
    for to_clear in (sys, warning_tests):
        try:
            to_clear.__warningregistry__.clear()
        except AttributeError:
            pass
    try:
        __warningregistry__.clear()
    except NameError:
        pass
    original_warnings = warning_tests.warnings
    original_filters = module.filters
    try:
        module.filters = original_filters[:]
        module.simplefilter("once")
        warning_tests.warnings = module
        yield
    finally:
        warning_tests.warnings = original_warnings
        module.filters = original_filters