Function skipif

IPython/testing/decorators.py:160–230

Make function raise SkipTest exception if skip_condition is true Parameters ---------- skip_condition : bool or callable Flag to determine whether to skip test. If the condition is a callable, it is used at runtime to dynamically make the decision. This is useful for

(skip_condition, msg=None)

# preserve function metadata better and allows the skip condition to be a
# callable.
def skipif(skip_condition, msg=None):
    ''' Make function raise SkipTest exception if skip_condition is true

    Parameters
    ----------

    skip_condition : bool or callable
      Flag to determine whether to skip test. 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.
    msg : string
      Message to give on raising a SkipTest exception.

    Returns
    -------
    decorator : function
      Decorator, which, when applied to a function, causes SkipTest
      to be raised when the skip_condition was True, and the function
      to be called normally otherwise.

    Notes
    -----
    You will see from the code that we had to further decorate the
    decorator with the nose.tools.make_decorator function in order to
    transmit function name, and various other metadata.
    '''

    def skip_decorator(f):
        # Local import to avoid a hard nose dependency and only incur the
        # import time overhead at actual test-time.
        import nose

        # Allow for both boolean or callable skip conditions.
        if callable(skip_condition):
            skip_val = skip_condition
        else:
            skip_val = lambda : skip_condition

        def get_msg(func,msg=None):
            """Skip message with information about function being skipped."""
            if msg is None: out = 'Test skipped due to test condition.'
            else: out = msg
            return "Skipping test: %s. %s" % (func.__name__,out)

        # We need to define *two* skippers because Python doesn't allow both
        # return with value and yield inside the same function.
        def skipper_func(*args, **kwargs):
            """Skipper for normal test functions."""
            if skip_val():
                raise nose.SkipTest(get_msg(f,msg))
            else:
                return f(*args, **kwargs)

        def skipper_gen(*args, **kwargs):
            """Skipper for test generators."""
            if skip_val():
                raise nose.SkipTest(get_msg(f,msg))