def METHOD_NAME(self):
    # ensure we use CUB block reduction and not CUB device reduction
    old_routine_accelerators = _accelerator.get_routine_accelerators()
    _accelerator.set_routine_accelerators([])
    a = cupy.random.random((10, 10))
    # this is the only function we can mock; the rest is cdef'd
    func_name = ''.join(('cupy._core._cub_reduction.',
                         '_SimpleCubReductionKernel_get_cached_function'))
    func = _cub_reduction._SimpleCubReductionKernel_get_cached_function
    with testing.AssertFunctionIsCalled(
            func_name, wraps=func, times_called=2):  # two passes
        a.sum()
    with testing.AssertFunctionIsCalled(
            func_name, wraps=func, times_called=1):  # one pass
        a.sum(axis=1)
    with testing.AssertFunctionIsCalled(
            func_name, wraps=func, times_called=0):  # not used
        a.sum(axis=0)
    _accelerator.set_routine_accelerators(old_routine_accelerators)