from __future__ import division, absolute_import, print_function

import numpy as np
from numpy.testing import TestCase, run_module_suite, assert_array_almost_equal

def fft1(x):
    L = len(x)
    phase = -2j*np.pi*(np.arange(L)/float(L))
    phase = np.arange(L).reshape(-1, 1) * phase
    return np.sum(x*np.exp(phase), axis=1)

class TestFFTShift(TestCase):

    def test_fft_n(self):
        self.assertRaises(ValueError, np.fft.fft, [1, 2, 3], 0)


class TestFFT1D(TestCase):

    def test_basic(self):
        rand = np.random.random
        x = rand(30) + 1j*rand(30)
        assert_array_almost_equal(fft1(x), np.fft.fft(x))


if __name__ == "__main__":
    run_module_suite()
