#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
Testing code for power spectra
"""
import numpy as np
from lasp import PowerSpectra, Window

def test_ps():
    """
    Check Parsevall for single-sided power spectra
    """
    nfft = 2048
    t = np.linspace(0, 1.0, nfft, endpoint=False)
    
    ps = PowerSpectra(nfft, Window.WindowType.Rectangular)
    
    sig = np.random.randn(nfft)
    freq = 4
    omg = 2*np.pi*freq
    # sig = 8*np.cos(omg*t)
    
    
    cps = ps.compute(sig[:,None])
    
    pow1 = np.sum(sig**2)/sig.size
    pow2 = np.sum((cps[:,0,0]).real)
    
    # print(pow1)
    # print(pow2)
    # plt.plot(cps[:,0,0])
    assert np.isclose(pow2 - pow1,0, atol=1e-1)
    
if __name__ == '__main__':
    test_ps()