#!/usr/bin/env python

"""
test sigmoid related functionality
"""

import os
import unittest
from tvii.sigmoid import sigmoid, sigmoidprime


class TestSigmoid(unittest.TestCase):

    def test_basic(self):
        """test two points of the sigmoid function"""

        answer = sigmoid([0,2])
        assert len(answer) == 2
        assert answer[0] == 0.5
        assert abs(answer[1] - 0.88079708) < 1e-6

    def test_derivative(self):

        self.assertAlmostEqual(sigmoidprime(0), 0.25)

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