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

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.