testing.dec.knownfailureif(fail_condition, msg=None)[source]#

Deprecated since version 1.21: This decorator is retained for compatibility with the nose testing framework, which is being phased out. Please use the nose2 or pytest frameworks instead.

Make function raise KnownFailureException exception if given condition is true.

If the condition is a callable, it is used at runtime to dynamically make the decision. This is useful for tests that may require costly imports, to delay the cost until the test suite is actually executed.

fail_conditionbool or callable

Flag to determine whether to mark the decorated test as a known failure (if True) or not (if False).

msgstr, optional

Message to give on raising a KnownFailureException exception. Default is None.


Decorator, which, when applied to a function, causes KnownFailureException to be raised when fail_condition is True, and the function to be called normally otherwise.


The decorator itself is decorated with the function in order to transmit function name, and various other metadata.