quicktex/tests/test_bc1.py

import unittest
import nose
from parameterized import parameterized_class
from s3tc import BC1Block
from images import Blocks
import quicktex.s3tc.bc1 as bc1
import quicktex.s3tc.interpolator as interpolator

ColorMode = bc1.BC1Encoder.ColorMode


class TestBC1Encoder(unittest.TestCase):
    """Test BC1 Encoder"""

    def setUp(self):
        self.bc1_encoder = bc1.BC1Encoder(5)

    def test_block_size(self):
        """Ensure encoded block size is 8 bytes."""
        out = self.bc1_encoder.encode_image(Blocks.greyscale, 4, 4)

        self.assertEqual(self.bc1_encoder.block_width, 4, 'incorrect reported block width')
        self.assertEqual(self.bc1_encoder.block_height, 4, 'incorrect reported block height')
        self.assertEqual(self.bc1_encoder.block_size, 8, 'incorrect reported block size')
        self.assertEqual(len(out), 8, 'incorrect returned block size')


def get_class_name_blocks(cls, num, params_dict):
    return "%s%s" % (cls.__name__, params_dict['color_mode'].name,)


@parameterized_class([
    {"color_mode": ColorMode.FourColor},
    {"color_mode": ColorMode.ThreeColor},
    {"color_mode": ColorMode.ThreeColorBlack},
], class_name_func=get_class_name_blocks)
class TestBC1EncoderBlocks(unittest.TestCase):
    """Test BC1 encoder with a variety of inputs with 3 color blocks disabled."""

    def setUp(self):
        self.bc1_encoder = bc1.BC1Encoder(5, self.color_mode)

    def test_block_4color(self):
        """Test encoder output with 4 color greyscale testblock."""
        out = BC1Block.frombytes(self.bc1_encoder.encode_image(Blocks.greyscale, 4, 4))
        selectors = [[0, 2, 3, 1]] * 4

        self.assertFalse(out.is_3color(), "returned block color mode for greyscale test block")
        self.assertEqual(selectors, out.selectors, "block has incorrect selectors for greyscale test block")

    def test_block_3color(self):
        """Test encoder output with 3 color test block."""
        out = BC1Block.frombytes(self.bc1_encoder.encode_image(Blocks.three_color, 4, 4))
        selectors = [[1, 2, 2, 0]] * 4

        if self.color_mode != ColorMode.FourColor:  # we only care about the selectors if we are in 3 color mode
            self.assertTrue(out.is_3color(), "returned 4-color block for 3 color test block")
            self.assertEqual(selectors, out.selectors, "block has incorrect selectors for 3 color test block")
        else:
            self.assertFalse(out.is_3color(), "return 3-color block in 4-color mode")

    def test_block_3color_black(self):
        """Test encoder output with 3 color test block with black pixels."""
        out = BC1Block.frombytes(self.bc1_encoder.encode_image(Blocks.three_color_black, 4, 4))
        selectors = [[3, 1, 2, 0]] * 4

        if self.color_mode == ColorMode.ThreeColorBlack:  # we only care about the selectors if we are in 3 color black mode
            self.assertTrue(out.is_3color_black(), "returned 4-color block for 3 color test block with black")
            self.assertEqual(selectors, out.selectors, "block has incorrect selectors for 3 color with black test block")
        else:
            self.assertFalse(out.is_3color_black(), "returned incorrect block color mode for 3 color with black test block")


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