import unittest, test.test_support

import colorsys



def frange(start, stop, step):

    while start <= stop:

        yield start

        start += step



class ColorsysTest(unittest.TestCase):



    def assertTripleEqual(self, tr1, tr2):

        self.assertEqual(len(tr1), 3)

        self.assertEqual(len(tr2), 3)

        self.assertAlmostEqual(tr1[0], tr2[0])

        self.assertAlmostEqual(tr1[1], tr2[1])

        self.assertAlmostEqual(tr1[2], tr2[2])



    def test_hsv_roundtrip(self):

        for r in frange(0.0, 1.0, 0.2):

            for g in frange(0.0, 1.0, 0.2):

                for b in frange(0.0, 1.0, 0.2):

                    rgb = (r, g, b)

                    self.assertTripleEqual(

                        rgb,

                        colorsys.hsv_to_rgb(*colorsys.rgb_to_hsv(*rgb))

                    )



    def test_hsv_values(self):

        values = [

            # rgb, hsv

            ((0.0, 0.0, 0.0), (  0  , 0.0, 0.0)), # black

            ((0.0, 0.0, 1.0), (4./6., 1.0, 1.0)), # blue

            ((0.0, 1.0, 0.0), (2./6., 1.0, 1.0)), # green

            ((0.0, 1.0, 1.0), (3./6., 1.0, 1.0)), # cyan

            ((1.0, 0.0, 0.0), (  0  , 1.0, 1.0)), # red

            ((1.0, 0.0, 1.0), (5./6., 1.0, 1.0)), # purple

            ((1.0, 1.0, 0.0), (1./6., 1.0, 1.0)), # yellow

            ((1.0, 1.0, 1.0), (  0  , 0.0, 1.0)), # white

            ((0.5, 0.5, 0.5), (  0  , 0.0, 0.5)), # grey

        ]

        for (rgb, hsv) in values:

            self.assertTripleEqual(hsv, colorsys.rgb_to_hsv(*rgb))

            self.assertTripleEqual(rgb, colorsys.hsv_to_rgb(*hsv))



    def test_hls_roundtrip(self):

        for r in frange(0.0, 1.0, 0.2):

            for g in frange(0.0, 1.0, 0.2):

                for b in frange(0.0, 1.0, 0.2):

                    rgb = (r, g, b)

                    self.assertTripleEqual(

                        rgb,

                        colorsys.hls_to_rgb(*colorsys.rgb_to_hls(*rgb))

                    )



    def test_hls_values(self):

        values = [

            # rgb, hls

            ((0.0, 0.0, 0.0), (  0  , 0.0, 0.0)), # black

            ((0.0, 0.0, 1.0), (4./6., 0.5, 1.0)), # blue

            ((0.0, 1.0, 0.0), (2./6., 0.5, 1.0)), # green

            ((0.0, 1.0, 1.0), (3./6., 0.5, 1.0)), # cyan

            ((1.0, 0.0, 0.0), (  0  , 0.5, 1.0)), # red

            ((1.0, 0.0, 1.0), (5./6., 0.5, 1.0)), # purple

            ((1.0, 1.0, 0.0), (1./6., 0.5, 1.0)), # yellow

            ((1.0, 1.0, 1.0), (  0  , 1.0, 0.0)), # white

            ((0.5, 0.5, 0.5), (  0  , 0.5, 0.0)), # grey

        ]

        for (rgb, hls) in values:

            self.assertTripleEqual(hls, colorsys.rgb_to_hls(*rgb))

            self.assertTripleEqual(rgb, colorsys.hls_to_rgb(*hls))



def test_main():

    test.test_support.run_unittest(ColorsysTest)



if __name__ == "__main__":

    test_main()

