import os
import sys
import tempfile
import unittest

sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
from png_compress import compress_png


class CompressPngTests(unittest.TestCase):
    def test_pixels_unchanged_and_smaller(self):
        from PIL import Image

        w = h = 64
        pixels = [(40, 80, 120, 255)] * (w * h)
        with tempfile.TemporaryDirectory() as d:
            path = os.path.join(d, "a.png")
            im = Image.new("RGBA", (w, h))
            im.putdata(pixels)
            im.save(path, format="PNG", compress_level=0, optimize=False)
            before = os.path.getsize(path)
            src_bytes = list(Image.open(path).getdata())
            sizes = compress_png(path)
            after_im = Image.open(path)
            self.assertEqual(list(after_im.getdata()), src_bytes)
            self.assertLess(sizes["after"], before)
            self.assertEqual(sizes["before"], before)


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