"""Test of fit module.

:Date: 2019-05-29

.. module:: test_fit
  :platform: *nix, Windows
  :synopsis: Test of fit module.

.. moduleauthor:: Daniel Weschke <daniel.weschke@directbox.de>
"""
import unittest

import os
import sys
from pylab import array, argmax, subplot, plot, title, xlim, show, gradient, linspace
sys.path.insert(0, os.path.abspath('..'))
from pylib.data import read
from pylib.numerical.fit import gauss_fit


class TestFit(unittest.TestCase):

  def test_gauss(self):
    """test function"""
    file_name = "test_fit.dat"
    x, y = read(file_name, 3, 2)

    subplot(2, 2, 1)
    plot(x, y, '.-')

    subplot(2, 2, 2)
    dx = x[1] - x[0]
    dydx = gradient(y, dx)  # central differences
    x_fit = linspace(x[0], x[-1], 150 if len(x) < 50 else len(x)*3)
    y_fit, popt, FWHM = gauss_fit(list(reversed(x)), list(reversed(dydx)), x_fit=x_fit, verbose=True)   # x must increase!
    plot(x, dydx, '.-')
    plot(x_fit, y_fit, 'r:')
    title('FWHM: %f' % FWHM)

    subplot(2, 2, 3)
    plot(x, y, '.-')
    xlim(popt[1]-2*FWHM, popt[1]+2*FWHM)

    subplot(2, 2, 4)
    plot(x, dydx, '.-')
    plot(x_fit, y_fit, 'r:')
    xlim(popt[1]-2*FWHM, popt[1]+2*FWHM)

    show()
    self.assertEqual(FWHM, 0.12975107355013618)


if __name__ == '__main__':
  unittest.main()