'Test 0 ** -1.
Note 2 ** <big number> returns an undefined value (depending
on the algorithm).'

def test_power_integer(self):

    dtype = np.int64
    f = vectorize(['int64(int64,    int64)'], nopython=True)(power)
    a = np.array([5, 0, 6], dtype=dtype)
    b = np.array([1, (-1), 2], dtype=dtype)
    expected = np.array([5, (- (2 ** 63)), 36], dtype=dtype)
    with self.check_warnings([]):
        res = f(a, b)
        self.assertPreciseEqual(res, expected)
