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_condition : bool or callable
Flag to determine whether to mark the decorated test as a known failure (if True) or not (if False).
msg : str, optional
Message to give on raising a KnownFailureException exception. Default is None.
decorator : function
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
nose.tools.make_decoratorfunction in order to transmit function name, and various other metadata.